C. Freiburg, Herimela Solomon-Degefa, Patrick Freiburg, Matthias Mörgelin, Véronique Bolduc, Sebastian Schmitz, Pierpaolo Ala, Francesco Muntoni, E. Behrmann, Carsten G. Bönnemann, A. Schiavinato, Mats Paulsson, R. Wagener
Collagen VI is a unique member of the collagen family. Its assembly is a complex multistep process and the vulnerability of the process is manifested in muscular diseases. Mutations in COL6A1, COL6A2, and COL6A3 lead to the severe Ullrich Congenital Muscular Dystrophy (UCMD) and a spectrum of disease of varying severity including the milder Bethlem muscular dystrophy. The recently identified dominant intronic mutation in COL6A1 ( c . 930 + 189 C > T ) leads to the partial in-frame insertion of a pseudoexon between exon 11 and exon 12. The pseudoexon is translated into 24 amino acid residues in the N-terminal region of the triple helix and results in the interruption of the typical G-X-Y motif. This recurrent de novo mutation leads to UCMD with a severe progression within the first decade of life. Here, we demonstrate that a mutation-specific antibody detects the mutant chain colocalizing with wild type collagen VI in the endomysium in patient muscle. Surprisingly, in the cell culture of patient dermal fibroblasts, the mutant chain is secreted as a single α chain, while in parallel, normal collagen VI tetramers are assembled with the wild-type α1 chain. The mutant chain cannot be incorporated into collagen VI tetramers but forms large aggregates in the extracellular matrix that may retain the ability to interact with collagen VI and potentially with other molecules. Also, α1 chain-deficient WI-26 VA4 cells transfected with the mutant α1 chain do not assemble collagen VI tetramers but, instead, form aggregates. Interestingly, both the wild type and the mutant single α1 chains form amorphous aggregates when expressed in HEK293 cells in the absence of α2 and α3 chains. The detection of aggregated, assembly incompetent, mutant collagen VI α1 chains provides novel insights into the disease pathophysiology of UCMD patients with the COL6A1 ( c . 930 + 189 C > T ) mutation.
{"title":"The UCMD-Causing COL6A1 (<math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M1\">\u0000 <mi>c</mi>\u0000 <mo>.</mo>\u0000 <mn>930</mn>\u0000 <mo>+</mo>\u0000 <mn>189</mn>\u0000 <mi>C</mi>\u0000 ","authors":"C. Freiburg, Herimela Solomon-Degefa, Patrick Freiburg, Matthias Mörgelin, Véronique Bolduc, Sebastian Schmitz, Pierpaolo Ala, Francesco Muntoni, E. Behrmann, Carsten G. Bönnemann, A. Schiavinato, Mats Paulsson, R. Wagener","doi":"10.1155/2023/6892763","DOIUrl":"https://doi.org/10.1155/2023/6892763","url":null,"abstract":"Collagen VI is a unique member of the collagen family. Its assembly is a complex multistep process and the vulnerability of the process is manifested in muscular diseases. Mutations in COL6A1, COL6A2, and COL6A3 lead to the severe Ullrich Congenital Muscular Dystrophy (UCMD) and a spectrum of disease of varying severity including the milder Bethlem muscular dystrophy. The recently identified dominant intronic mutation in COL6A1 (\u0000 \u0000 c\u0000 .\u0000 930\u0000 +\u0000 189\u0000 C\u0000 >\u0000 T\u0000 \u0000 ) leads to the partial in-frame insertion of a pseudoexon between exon 11 and exon 12. The pseudoexon is translated into 24 amino acid residues in the N-terminal region of the triple helix and results in the interruption of the typical G-X-Y motif. This recurrent de novo mutation leads to UCMD with a severe progression within the first decade of life. Here, we demonstrate that a mutation-specific antibody detects the mutant chain colocalizing with wild type collagen VI in the endomysium in patient muscle. Surprisingly, in the cell culture of patient dermal fibroblasts, the mutant chain is secreted as a single α chain, while in parallel, normal collagen VI tetramers are assembled with the wild-type α1 chain. The mutant chain cannot be incorporated into collagen VI tetramers but forms large aggregates in the extracellular matrix that may retain the ability to interact with collagen VI and potentially with other molecules. Also, α1 chain-deficient WI-26 VA4 cells transfected with the mutant α1 chain do not assemble collagen VI tetramers but, instead, form aggregates. Interestingly, both the wild type and the mutant single α1 chains form amorphous aggregates when expressed in HEK293 cells in the absence of α2 and α3 chains. The detection of aggregated, assembly incompetent, mutant collagen VI α1 chains provides novel insights into the disease pathophysiology of UCMD patients with the COL6A1 (\u0000 \u0000 c\u0000 .\u0000 930\u0000 +\u0000 189\u0000 C\u0000 >\u0000 T\u0000 \u0000 ) mutation.","PeriodicalId":13061,"journal":{"name":"Human Mutation","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2023-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43551312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Bouvet, A. Blondel, Jean-Madeleine de Sainte Agathe, G. Leroy, C. Saint-Martin, C. Bellanné-Chantelot
Variants in GCK, HNF1A, and HNF4A genes are the three main causes of monogenic diabetes. Determining the molecular etiology is essential for patients with monogenic diabetes to benefit from the most appropriate treatment. The increasing number of variants of unknown significance (VUS) is a major issue in genetic diagnosis, and assessing the impact of variants on RNA splicing is challenging, particularly for genes expressed in tissues not easily accessible as in monogenic diabetes. The in vitro functional splicing assay based on a minigene construct is an appropriate approach. Here, we performed in silico analysis using SpliceAI and SPiP and prioritized 36 spliceogenic variants in GCK, HNF1A, and HNF4A. Predictions were secondarily compared with Pangolin and AbSplice-DNA bioinformatics tools which include tissue-specific annotations. We assessed the effect of selected variants on RNA splicing using minigene assays. These assays validated splicing defects for 33 out of 36 spliceogenic variants consisting of exon skipping (15%), exonic deletions (18%), intronic retentions (24%), and complex splicing patterns (42%). This provided additional evidence to reclassify 23 out of 31 (74%) VUS including missense, synonymous, and intronic noncanonical splice site variants as likely pathogenic variants. Comparison of in silico analysis with minigene results showed the robustness of bioinformatics tools to prioritize spliceogenic variants, but revealed inconsistencies in the location of cryptic splice sites underlying the importance of confirming predicted splicing alterations with functional splicing assays. Our study underlines the feasibility and the benefits of implementing minigene-splicing assays in the genetic testing of monogenic diabetes after a prior in-depth in silico analysis.
{"title":"Evaluation in Monogenic Diabetes of the Impact of GCK, HNF1A, and HNF4A Variants on Splicing through the Combined Use of In Silico Tools and Minigene Assays","authors":"D. Bouvet, A. Blondel, Jean-Madeleine de Sainte Agathe, G. Leroy, C. Saint-Martin, C. Bellanné-Chantelot","doi":"10.1155/2023/6661013","DOIUrl":"https://doi.org/10.1155/2023/6661013","url":null,"abstract":"Variants in GCK, HNF1A, and HNF4A genes are the three main causes of monogenic diabetes. Determining the molecular etiology is essential for patients with monogenic diabetes to benefit from the most appropriate treatment. The increasing number of variants of unknown significance (VUS) is a major issue in genetic diagnosis, and assessing the impact of variants on RNA splicing is challenging, particularly for genes expressed in tissues not easily accessible as in monogenic diabetes. The in vitro functional splicing assay based on a minigene construct is an appropriate approach. Here, we performed in silico analysis using SpliceAI and SPiP and prioritized 36 spliceogenic variants in GCK, HNF1A, and HNF4A. Predictions were secondarily compared with Pangolin and AbSplice-DNA bioinformatics tools which include tissue-specific annotations. We assessed the effect of selected variants on RNA splicing using minigene assays. These assays validated splicing defects for 33 out of 36 spliceogenic variants consisting of exon skipping (15%), exonic deletions (18%), intronic retentions (24%), and complex splicing patterns (42%). This provided additional evidence to reclassify 23 out of 31 (74%) VUS including missense, synonymous, and intronic noncanonical splice site variants as likely pathogenic variants. Comparison of in silico analysis with minigene results showed the robustness of bioinformatics tools to prioritize spliceogenic variants, but revealed inconsistencies in the location of cryptic splice sites underlying the importance of confirming predicted splicing alterations with functional splicing assays. Our study underlines the feasibility and the benefits of implementing minigene-splicing assays in the genetic testing of monogenic diabetes after a prior in-depth in silico analysis.","PeriodicalId":13061,"journal":{"name":"Human Mutation","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49033606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Arnaud, Margaux Cadenet, Zakaria Mougin, C. Le Goff, S. Perbet, Mathilde Francois, S. Dupuis-Girod, C. Boileau, N. Hanna
Rare pathogenic variants in the MYH11 gene are responsible for thoracic aortic aneurysms and dissections. They are usually heterozygous missense variants or in-frame deletions of several amino acids without alteration of the reading frame and mainly affect the coiled-coil domain of the protein. Variants leading to a premature stop codon have been described in patients with another phenotype, megacystis-microcolon-intestinal hypoperistalsis syndrome, with an autosomal recessive inheritance. The physiopathological mechanisms arising from the different genetic alterations affecting the MYH11 gene are still poorly understood. Consequently, variants of unknown significance are relatively frequent in this gene. We have identified a variant affecting the consensus donor splice site of exon 29 in the MYH11 gene in a patient who suddenly died from an aortic type A dissection at the age of 23 years old. A transcript analysis on cultured fibroblasts has highlighted several abnormal transcripts including two in-frame transcripts. The first one is a deletion of the last 78 nucleotides of exon 29, corresponding to the use of a cryptic alternative donor splice site; the second one corresponds to an exon 29 skipping. Familial screening has revealed that this molecular event occurred de novo in the proband. Taken together, these experiments allowed us to classify this variant as pathogenic. This case underlines the challenging aspect of the discovery of variations in the MYH11 gene for which the consequences on splicing should be systematically studied in detail.
{"title":"Early-Onset Aortic Dissection: Characterization of a New Pathogenic Splicing Variation in the MYH11 Gene with Several In-Frame Abnormal Transcripts","authors":"P. Arnaud, Margaux Cadenet, Zakaria Mougin, C. Le Goff, S. Perbet, Mathilde Francois, S. Dupuis-Girod, C. Boileau, N. Hanna","doi":"10.1155/2023/1410230","DOIUrl":"https://doi.org/10.1155/2023/1410230","url":null,"abstract":"Rare pathogenic variants in the MYH11 gene are responsible for thoracic aortic aneurysms and dissections. They are usually heterozygous missense variants or in-frame deletions of several amino acids without alteration of the reading frame and mainly affect the coiled-coil domain of the protein. Variants leading to a premature stop codon have been described in patients with another phenotype, megacystis-microcolon-intestinal hypoperistalsis syndrome, with an autosomal recessive inheritance. The physiopathological mechanisms arising from the different genetic alterations affecting the MYH11 gene are still poorly understood. Consequently, variants of unknown significance are relatively frequent in this gene. We have identified a variant affecting the consensus donor splice site of exon 29 in the MYH11 gene in a patient who suddenly died from an aortic type A dissection at the age of 23 years old. A transcript analysis on cultured fibroblasts has highlighted several abnormal transcripts including two in-frame transcripts. The first one is a deletion of the last 78 nucleotides of exon 29, corresponding to the use of a cryptic alternative donor splice site; the second one corresponds to an exon 29 skipping. Familial screening has revealed that this molecular event occurred de novo in the proband. Taken together, these experiments allowed us to classify this variant as pathogenic. This case underlines the challenging aspect of the discovery of variations in the MYH11 gene for which the consequences on splicing should be systematically studied in detail.","PeriodicalId":13061,"journal":{"name":"Human Mutation","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49534373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aurélie Gouronc, Elodie Javey, Anne-Sophie Leuvrey, Elsa Nourisson, Sylvie Friedmann, Valérie Reichert, N. Derive, C. Francannet, B. Keren, J. Lévy, M. Planes, L. Ruaud, J. Amiel, H. Dollfus, Sophie Scheidecker, J. Muller
Ciliopathies are rare genetic disorders caused by dysfunction of the primary or motile cilia. Their mode of inheritance is mostly autosomal recessive with biallelic pathogenic variants inherited from the parents. However, exceptions exist such as uniparental disomy (UPD) or the appearance of a de novo pathogenic variant in trans of an inherited pathogenic variant. These two genetic mechanisms are expected to be extremely rare, and few data are available in the literature, especially regarding ciliopathies. In this study, we investigated 940 individuals (812 families) with a suspected ciliopathy by Sanger sequencing, high-throughput sequencing and/or SNP array analysis and performed a literature review of UPD and de novo variants in ciliopathies. In a large cohort of 623 individuals (511 families) with a molecular diagnosis of ciliopathy (mainly Bardet-Biedl syndrome and Alström syndrome), we identified five UPD, revealing an inherited pathogenic variant and five pathogenic variants of de novo appearance (in trans of another pathogenic variant). Moreover, from these ten cases, we reported 15 different pathogenic variants of which five are novel. We demonstrated a relatively high prevalence of UPD and de novo variants in a large cohort of ciliopathies and highlighted the importance of identifying such rare genetic events, especially for genetic counseling.
{"title":"Unexpected Inheritance Patterns in a Large Cohort of Patients with a Suspected Ciliopathy","authors":"Aurélie Gouronc, Elodie Javey, Anne-Sophie Leuvrey, Elsa Nourisson, Sylvie Friedmann, Valérie Reichert, N. Derive, C. Francannet, B. Keren, J. Lévy, M. Planes, L. Ruaud, J. Amiel, H. Dollfus, Sophie Scheidecker, J. Muller","doi":"10.1155/2023/2564200","DOIUrl":"https://doi.org/10.1155/2023/2564200","url":null,"abstract":"Ciliopathies are rare genetic disorders caused by dysfunction of the primary or motile cilia. Their mode of inheritance is mostly autosomal recessive with biallelic pathogenic variants inherited from the parents. However, exceptions exist such as uniparental disomy (UPD) or the appearance of a de novo pathogenic variant in trans of an inherited pathogenic variant. These two genetic mechanisms are expected to be extremely rare, and few data are available in the literature, especially regarding ciliopathies. In this study, we investigated 940 individuals (812 families) with a suspected ciliopathy by Sanger sequencing, high-throughput sequencing and/or SNP array analysis and performed a literature review of UPD and de novo variants in ciliopathies. In a large cohort of 623 individuals (511 families) with a molecular diagnosis of ciliopathy (mainly Bardet-Biedl syndrome and Alström syndrome), we identified five UPD, revealing an inherited pathogenic variant and five pathogenic variants of de novo appearance (in trans of another pathogenic variant). Moreover, from these ten cases, we reported 15 different pathogenic variants of which five are novel. We demonstrated a relatively high prevalence of UPD and de novo variants in a large cohort of ciliopathies and highlighted the importance of identifying such rare genetic events, especially for genetic counseling.","PeriodicalId":13061,"journal":{"name":"Human Mutation","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64792931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Tsuneura, Taeko Kawai, Keitaro Yamada, S. Aoki, M. Nakashima, S. Eda, Tohru Matsuki, M. Nishikawa, K. Nagata, Y. Enokido, H. Saitsu, A. Nakayama
Whole exome sequencing/whole genome sequencing has accelerated the identification of novel genes associated with intellectual disabilities (ID), and RAB11A which encodes an endosomal small GTPase is among them. However, consequent neural abnormalities have not been studied, and pathophysiological mechanisms underlying the ID and other clinical features in patients harboring RAB11A variants remain to be clarified. In this study, we report a novel de novo missense variant in RAB11A, NM_004663.5: c . 98 G > C , which would result in NP_004654.1: p.(R33P) substitution, in a Japanese boy with severe ID and hypomyelination. Biochemical analyses indicated that the RAB11A-R33P is a gain-of-function, constitutively active variant. Accordingly, the introduction of the RAB11A-R33P promoted neurite extension in neurons like a known constitutively active variant Rab11A-Q70L. In addition, the RAB11A-R33P induced excessive branching with thinner processes in oligodendrocytes. These results indicate that the gain-of-function RAB11A-R33P variant in association with ID and hypomyelination affects neural cells and can be deleterious to them, especially to oligodendrocytes, and strongly suggest the pathogenic role of the RAB11A-R33P variant in neurodevelopmental impairments, especially in the hypomyelination.
全外显子组测序/全基因组测序加速了与智力残疾(ID)相关的新基因的鉴定，编码内体小GTPase的RAB11A就是其中之一。然而，随之而来的神经异常尚未被研究，RAB11A变异患者ID和其他临床特征的病理生理机制仍有待阐明。在这项研究中，我们报道了RAB11A基因NM_004663.5: c中一个新的从头错义变异。98 G > C，这将导致NP_004654.1: p.(R33P)替代，在一个日本男孩严重ID和髓鞘化低。生化分析表明RAB11A-R33P是一种功能获得的组成活性变体。因此，RAB11A-R33P的引入促进了神经元中神经突的延伸，如已知的构成活性变体Rab11A-Q70L。此外，RAB11A-R33P诱导少突胶质细胞分支过细。这些结果表明，与ID和低髓鞘形成相关的RAB11A-R33P变异的功能获得可影响神经细胞并对其有害，特别是对少突胶质细胞，并强烈提示RAB11A-R33P变异在神经发育障碍，特别是低髓鞘形成中的致病作用。
{"title":"A Novel Constitutively Active \u0000 c\u0000 .\u0000 98\u0000 G\u0000 >\u0000 C\u0000 , p.(R33P) Variant in RAB11A Associated with Intellectual Disability Promotes Neuritogenesis and Affects Oligodendroglial Arborization","authors":"Y. Tsuneura, Taeko Kawai, Keitaro Yamada, S. Aoki, M. Nakashima, S. Eda, Tohru Matsuki, M. Nishikawa, K. Nagata, Y. Enokido, H. Saitsu, A. Nakayama","doi":"10.1155/2023/8126544","DOIUrl":"https://doi.org/10.1155/2023/8126544","url":null,"abstract":"Whole exome sequencing/whole genome sequencing has accelerated the identification of novel genes associated with intellectual disabilities (ID), and RAB11A which encodes an endosomal small GTPase is among them. However, consequent neural abnormalities have not been studied, and pathophysiological mechanisms underlying the ID and other clinical features in patients harboring RAB11A variants remain to be clarified. In this study, we report a novel de novo missense variant in RAB11A, NM_004663.5: \u0000 \u0000 c\u0000 .\u0000 98\u0000 G\u0000 >\u0000 C\u0000 \u0000 , which would result in NP_004654.1: p.(R33P) substitution, in a Japanese boy with severe ID and hypomyelination. Biochemical analyses indicated that the RAB11A-R33P is a gain-of-function, constitutively active variant. Accordingly, the introduction of the RAB11A-R33P promoted neurite extension in neurons like a known constitutively active variant Rab11A-Q70L. In addition, the RAB11A-R33P induced excessive branching with thinner processes in oligodendrocytes. These results indicate that the gain-of-function RAB11A-R33P variant in association with ID and hypomyelination affects neural cells and can be deleterious to them, especially to oligodendrocytes, and strongly suggest the pathogenic role of the RAB11A-R33P variant in neurodevelopmental impairments, especially in the hypomyelination.","PeriodicalId":13061,"journal":{"name":"Human Mutation","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42621457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maria Sáez González, Kes Kloosterhuis, L. A. van de Pol, F. Baas, H. Mikkers
GNAO1 disorder is a rare autosomal dominant neurodevelopmental syndrome that is clinically manifested by developmental delay, (early onset) epilepsy, and movement disorders. Clinical symptoms appear very heterogeneous in nature and severity, as well as the response of GNAO1 patients to available medication varies. Pathogenic GNAO1 variants have been found mainly scattered throughout the gene although certain mutation hotspots affecting the function of the encoded Gαo proteins exist. GNAO1 variants only partially explain the diverse phenotypic spectrum observed but full stratification has been hampered by the limited number of patients. The aim of this review was to generate a comprehensive overview of the germline variants in GNAO1 and provide insight into the phenotypic diversity of the GNAO1 disorder. We compiled a list of 398 GNAO1 germline variants. In addition, we provide the GNAO1 variants and associated phenotypes of 282 GNAO1 patients reported in case reports, whole genome sequencing studies, genetic variant databases, and 8 novel GNAO1 patients that were not described before. This has resulted in a list of 107 (likely) pathogenic GNAO1 variants. Available phenotypic data was utilized to quantitatively assess the genetic and phenotypic diversity of the GNAO1 disorder and discuss the outcomes. This inventory forms the basis for a GNAO1 variant database that will be updated continuously. Moreover, it will aid genetic diagnostics, medical decision-making, prognostication, and research on the mechanisms underlying the GNAO1 disorder.
{"title":"Phenotypic Diversity in GNAO1 Patients: A Comprehensive Overview of Variants and Phenotypes","authors":"Maria Sáez González, Kes Kloosterhuis, L. A. van de Pol, F. Baas, H. Mikkers","doi":"10.1155/2023/6628283","DOIUrl":"https://doi.org/10.1155/2023/6628283","url":null,"abstract":"GNAO1 disorder is a rare autosomal dominant neurodevelopmental syndrome that is clinically manifested by developmental delay, (early onset) epilepsy, and movement disorders. Clinical symptoms appear very heterogeneous in nature and severity, as well as the response of GNAO1 patients to available medication varies. Pathogenic GNAO1 variants have been found mainly scattered throughout the gene although certain mutation hotspots affecting the function of the encoded Gαo proteins exist. GNAO1 variants only partially explain the diverse phenotypic spectrum observed but full stratification has been hampered by the limited number of patients. The aim of this review was to generate a comprehensive overview of the germline variants in GNAO1 and provide insight into the phenotypic diversity of the GNAO1 disorder. We compiled a list of 398 GNAO1 germline variants. In addition, we provide the GNAO1 variants and associated phenotypes of 282 GNAO1 patients reported in case reports, whole genome sequencing studies, genetic variant databases, and 8 novel GNAO1 patients that were not described before. This has resulted in a list of 107 (likely) pathogenic GNAO1 variants. Available phenotypic data was utilized to quantitatively assess the genetic and phenotypic diversity of the GNAO1 disorder and discuss the outcomes. This inventory forms the basis for a GNAO1 variant database that will be updated continuously. Moreover, it will aid genetic diagnostics, medical decision-making, prognostication, and research on the mechanisms underlying the GNAO1 disorder.","PeriodicalId":13061,"journal":{"name":"Human Mutation","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45909106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gerard C. P. Schaafsma, J. Väliaho, Qing Wang, A. Berglöf, R. Zain, C. I. E. Smith, M. Vihinen
BTKbase is an international database for disease-causing variants in Bruton tyrosine kinase (BTK) leading to X-linked agammaglobulinemia (XLA), a rare primary immunodeficiency of antibody production. BTKbase was established in 1994 as one of the first publicly available variation databases. The number of cases has more than doubled since the last update; it now contains information for 2310 DNA variants in 2291 individuals. 1025 of the DNA variants are unique. The human genome contains more than 500 protein kinases, among which BTK has the largest number of unique disease-causing variants. The current version of BTKbase has numerous novel features: the database has been reformatted, it has moved to LOVD database management system, it has been internally harmonized, etc. Systematics and standardization have been increased, including Variation Ontology annotations for variation types. There are some regions with lower than expected variation frequency and some hotspots for variations. BTKbase contains, in addition to variant descriptions at DNA, RNA and protein levels, also laboratory parameters and clinical features for many patients. BTKbase has served clinical and research communities in the diagnosis of XLA cases and provides general insight into effects of variations, especially in signalling pathways. Amino acid substitutions and their effects were investigated, predicted, and visualized at 3D level in the protein domains. BTKbase is freely available.
{"title":"BTKbase, Bruton Tyrosine Kinase Variant Database in X-Linked Agammaglobulinemia: Looking Back and Ahead","authors":"Gerard C. P. Schaafsma, J. Väliaho, Qing Wang, A. Berglöf, R. Zain, C. I. E. Smith, M. Vihinen","doi":"10.1155/2023/5797541","DOIUrl":"https://doi.org/10.1155/2023/5797541","url":null,"abstract":"BTKbase is an international database for disease-causing variants in Bruton tyrosine kinase (BTK) leading to X-linked agammaglobulinemia (XLA), a rare primary immunodeficiency of antibody production. BTKbase was established in 1994 as one of the first publicly available variation databases. The number of cases has more than doubled since the last update; it now contains information for 2310 DNA variants in 2291 individuals. 1025 of the DNA variants are unique. The human genome contains more than 500 protein kinases, among which BTK has the largest number of unique disease-causing variants. The current version of BTKbase has numerous novel features: the database has been reformatted, it has moved to LOVD database management system, it has been internally harmonized, etc. Systematics and standardization have been increased, including Variation Ontology annotations for variation types. There are some regions with lower than expected variation frequency and some hotspots for variations. BTKbase contains, in addition to variant descriptions at DNA, RNA and protein levels, also laboratory parameters and clinical features for many patients. BTKbase has served clinical and research communities in the diagnosis of XLA cases and provides general insight into effects of variations, especially in signalling pathways. Amino acid substitutions and their effects were investigated, predicted, and visualized at 3D level in the protein domains. BTKbase is freely available.","PeriodicalId":13061,"journal":{"name":"Human Mutation","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49472020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Durkie, C. Watson, P. Winship, Anne-Cecile Hogg, R. Nyanhete, S. Cooley, M. Valluru, C. Shaw-Smith, C. Bingham, M. Gilchrist, Janna Kenny, G. Consortium, A. Ong
Biallelic PKD1 variants, including hypomorphic variants, can cause very early onset polycystic kidney disease (VEO-PKD). A family with unexplained recurrent VEO-PKD and neonatal demise in one dizygotic twin was referred for clinical testing. Further individuals with the putative hypomorphic PKD1 variant, p.(Ile3167Phe), were identified from the UK 100,000 genomes project (100 K), UK Biobank (UKBB), and a review of the literature. We identified a likely pathogenic PKD1 missense paternal variant and the putative hypomorphic PKD1 variant from the unaffected mother in the deceased twin but only the paternal PKD1 variant in the surviving dizygotic twin. Analysis of 100 K cases identified a second family with two siblings with similar biallelic inheritance who presented at birth with VEO-PKD and reached kidney failure in their teens unlike other affected relatives. Finally, a survey of 618 UKBB cases confirmed that adult patients monoallelic for PKD1 p.(Ile3167Phe) had normal kidney function. Our data reveals that p.(Ile3167Phe) is the second most common PKD1 hypomorphic variant identified and is neutral in heterozygosity but is associated with VEO-PKD when inherited in trans with a pathogenic PKD1 variant. Care should be taken to ensure that it is not automatically filtered from sequence data for VEO cases.
{"title":"The Common PKD1 p.(Ile3167Phe) Variant Is Hypomorphic and Associated with Very Early Onset, Biallelic Polycystic Kidney Disease","authors":"M. Durkie, C. Watson, P. Winship, Anne-Cecile Hogg, R. Nyanhete, S. Cooley, M. Valluru, C. Shaw-Smith, C. Bingham, M. Gilchrist, Janna Kenny, G. Consortium, A. Ong","doi":"10.1155/2023/5597005","DOIUrl":"https://doi.org/10.1155/2023/5597005","url":null,"abstract":"Biallelic PKD1 variants, including hypomorphic variants, can cause very early onset polycystic kidney disease (VEO-PKD). A family with unexplained recurrent VEO-PKD and neonatal demise in one dizygotic twin was referred for clinical testing. Further individuals with the putative hypomorphic PKD1 variant, p.(Ile3167Phe), were identified from the UK 100,000 genomes project (100 K), UK Biobank (UKBB), and a review of the literature. We identified a likely pathogenic PKD1 missense paternal variant and the putative hypomorphic PKD1 variant from the unaffected mother in the deceased twin but only the paternal PKD1 variant in the surviving dizygotic twin. Analysis of 100 K cases identified a second family with two siblings with similar biallelic inheritance who presented at birth with VEO-PKD and reached kidney failure in their teens unlike other affected relatives. Finally, a survey of 618 UKBB cases confirmed that adult patients monoallelic for PKD1 p.(Ile3167Phe) had normal kidney function. Our data reveals that p.(Ile3167Phe) is the second most common PKD1 hypomorphic variant identified and is neutral in heterozygosity but is associated with VEO-PKD when inherited in trans with a pathogenic PKD1 variant. Care should be taken to ensure that it is not automatically filtered from sequence data for VEO cases.","PeriodicalId":13061,"journal":{"name":"Human Mutation","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49326034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Li Wang, Y. Qiu, Kuerbanjiang Abuduxikuer, Neng-Li Wang, Zhong-Die Li, Ye Cheng, Yi Lu, Xin-Bao Xie, Qing-He Xing, Jian-She Wang
Biallelic MYO5B variants have been associated with familial intrahepatic cholestasis (FIC) with low serum gamma-glutamyltransferase (GGT). Intronic or synonymous variants outside of canonical splice sites (hereinafter referred to as noncanonical variants) with uncertain significance were identified in MYO5B posing a challenge in clinical interpretation. This study is aimed at assessing the effects of these variants on premessenger RNA (pre-mRNA) splicing to improve recognition of pathogenic spliceogenic variants in MYO5B and better characterize the MYO5B genetic variation spectrum. Disease-associated MYO5B noncanonical variants were collected from the literature or newly identified low GGT cholestasis patients. In silico splicing predictions were performed to prioritize potential pathogenic variants. Minigene splicing assays were performed to determine their splicing patterns, with confirmation by blood RNA analysis in one case. Eleven (five novel) noncanonical variants with uncertain significance were identified. Minigene splicing assays revealed that three variants (c.2090+3A>T, c.2414+5G>T, and c.613-11G>A) caused complete aberrations, five variants (c.2349A>G/p.(=), c.4221G>A/p.(=), c.1322+5G>A, c.1669-35A>C, and c.3045+3A>T) caused predominant aberrations, and three variants (c.4852+11A>G, c.455+8T>C, and c.2415-6C>G) had no effect on pre-mRNA splicing. Patient-derived RNA analysis showed consistent results. Based on our results, eight variants were reclassified as likely pathogenic and three as likely benign. Combining the clinical features and the above analysis, the diagnosis of MYO5B-associated FIC could be made in three new patients. In conclusion, we characterized the splicing patterns of MYO5B noncanonical variants and suggest that RNA analysis should be routinely included in clinical diagnostics to provide essential evidence for the interpretation of variants.
{"title":"Splicing Analysis of MYO5B Noncanonical Variants in Patients with Low Gamma-Glutamyltransferase Cholestasis","authors":"Li Wang, Y. Qiu, Kuerbanjiang Abuduxikuer, Neng-Li Wang, Zhong-Die Li, Ye Cheng, Yi Lu, Xin-Bao Xie, Qing-He Xing, Jian-She Wang","doi":"10.1155/2023/8848362","DOIUrl":"https://doi.org/10.1155/2023/8848362","url":null,"abstract":"Biallelic MYO5B variants have been associated with familial intrahepatic cholestasis (FIC) with low serum gamma-glutamyltransferase (GGT). Intronic or synonymous variants outside of canonical splice sites (hereinafter referred to as noncanonical variants) with uncertain significance were identified in MYO5B posing a challenge in clinical interpretation. This study is aimed at assessing the effects of these variants on premessenger RNA (pre-mRNA) splicing to improve recognition of pathogenic spliceogenic variants in MYO5B and better characterize the MYO5B genetic variation spectrum. Disease-associated MYO5B noncanonical variants were collected from the literature or newly identified low GGT cholestasis patients. In silico splicing predictions were performed to prioritize potential pathogenic variants. Minigene splicing assays were performed to determine their splicing patterns, with confirmation by blood RNA analysis in one case. Eleven (five novel) noncanonical variants with uncertain significance were identified. Minigene splicing assays revealed that three variants (c.2090+3A>T, c.2414+5G>T, and c.613-11G>A) caused complete aberrations, five variants (c.2349A>G/p.(=), c.4221G>A/p.(=), c.1322+5G>A, c.1669-35A>C, and c.3045+3A>T) caused predominant aberrations, and three variants (c.4852+11A>G, c.455+8T>C, and c.2415-6C>G) had no effect on pre-mRNA splicing. Patient-derived RNA analysis showed consistent results. Based on our results, eight variants were reclassified as likely pathogenic and three as likely benign. Combining the clinical features and the above analysis, the diagnosis of MYO5B-associated FIC could be made in three new patients. In conclusion, we characterized the splicing patterns of MYO5B noncanonical variants and suggest that RNA analysis should be routinely included in clinical diagnostics to provide essential evidence for the interpretation of variants.","PeriodicalId":13061,"journal":{"name":"Human Mutation","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47549997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fatty acid oxidation disorders (FAODs) are a group of rare, autosomal recessive, metabolic disorders with clinical symptoms from mild types of fatigue, muscle weakness to severe types of hypoketotic hypoglycemia, (cardio)myopathy, arrhythmia, and rhabdomyolysis, especially during prolonged fasting, exercise, and illness. There are eleven diseases caused by thirteen FAOD genes (SLC22A5, ETFDH, ETFA, ETFB, SLC25A20, ACADS, ACADM, ACADVL, ACAT1, CPT1A, CPT2, HADHA, and HADHB) which are specific enzymes or transport proteins involved in the mitochondrial catabolism of fatty acids. We built the LOVD database for FAODs focused on the Chinese population, in which we recorded all the reported variants by literature peer review. In addition, the unpublished variant data of patients from Zhejiang province were also incorporated into the database. Currently, a total of 538 unique variants have been recorded. We also compared the incidence of high-frequency variants of certain FAOD genes among different populations. The database would provide the guidance for genetic screening of Chinese patients.
{"title":"A Comprehensive LOVD Database for Fatty Acid Oxidation Disorders in Chinese Populations","authors":"Ting Zhang, Zinan Yu, Lingwei Hu, Chao Zhang, Haixia Miao, Rulai Yang, Ming Qi, Benqing Wu, Xinwen Huang","doi":"10.1155/2023/5493978","DOIUrl":"https://doi.org/10.1155/2023/5493978","url":null,"abstract":"Fatty acid oxidation disorders (FAODs) are a group of rare, autosomal recessive, metabolic disorders with clinical symptoms from mild types of fatigue, muscle weakness to severe types of hypoketotic hypoglycemia, (cardio)myopathy, arrhythmia, and rhabdomyolysis, especially during prolonged fasting, exercise, and illness. There are eleven diseases caused by thirteen FAOD genes (SLC22A5, ETFDH, ETFA, ETFB, SLC25A20, ACADS, ACADM, ACADVL, ACAT1, CPT1A, CPT2, HADHA, and HADHB) which are specific enzymes or transport proteins involved in the mitochondrial catabolism of fatty acids. We built the LOVD database for FAODs focused on the Chinese population, in which we recorded all the reported variants by literature peer review. In addition, the unpublished variant data of patients from Zhejiang province were also incorporated into the database. Currently, a total of 538 unique variants have been recorded. We also compared the incidence of high-frequency variants of certain FAOD genes among different populations. The database would provide the guidance for genetic screening of Chinese patients.","PeriodicalId":13061,"journal":{"name":"Human Mutation","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48536362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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