Clinical Genetics最新文献

Intellectual Developmental Disorder with Dysmorphic Facies and Ptosis (IDDDFP) is a rare autosomal dominant syndrome caused by pathogenic variants in the BRPF1 gene, which is critical for chromatin regulation. This study expands the clinical and molecular spectrum of IDDDFP by analysing 29 new patients from 20 families with confirmed BRPF1 variants. Our cohort presented with a wide range of clinical features including developmental delay, intellectual disability (ID) and characteristic dysmorphic facial features such as ptosis, blepharophimosis and a broad nasal bridge. New phenotypic features identified include palpebral oedema, laterally elongated eyebrows, low hanging columella and hypertrichosis. Neuropsychological assessment reveals a predominance of mild to moderate ID, with cognitive profiles showing variability in verbal and visual processing. Structural abnormalities such as agenesis of the corpus callosum and ocular defects were noted, consistent with previous studies but with some differences. Familial analysis revealed variability in clinical expression. Our findings highlight the diverse clinical manifestations of BRPF1-related disorders and suggest that comprehensive ophthalmological evaluation is essential for the management of these patients.

This retrospective cohort study aimed to define the optimal Regions of Homozygosity (ROH) size cut-offs for prediction of morbidity, based on 13 483 Chromosomal Microarray Analyses (CMA). Receiver operating characteristic (ROC) curves were generated, and area under the curve (AUC) was used to assess the predictive capability of total ROH percentage (TRPS), ROH number and ROH segment size in distinguishing between healthy (n=6,196) and affected (n=6,839) cohorts. The metrics were examined for telomeric and interstitial segments, distinct TRPS categories, and across different ancestral origins. ROH segments were identified in 13 035 samples (96.7%), encompassing 66 710 ROH segments. Significant differences in TRPS and ROH segment size were observed between healthy and affected cohorts (p=0.012 and p < 0.001, respectively). However, no clinically significant thresholds could be established based on ROC curves for TRPS and ROH number per sample, as well as for ROH size (AUC 0.64, 0.55, and 0.62, respectively, Figure 1). The same was noted for telomeric versus interstitial locations, various origins, and subcategories of TRPS. In conclusion, this study highlights the complexity of ROH interpretation and emphasizes the importance of tailored reporting strategies in clinical practice. Our findings underscore the need for context-specific reporting guidelines and further research, particularly in consanguineous populations.

Renal ciliopathies are a genetically and phenotypically heterogeneous group of diseases characterized by cystic and dysplastic kidneys. The aim of this study was to investigate the correlation between genetic changes that cause renal ciliopathies and phenotypic outcomes. The study group consisted of 137 patients diagnosed with renal ciliopathy disease. One hundred nineteen patients had ADPKD phenotype, 7 patients had ARPKD phenotype, 4 patients had nephronophthisis, 1 patient had Senior-Loken syndrome, 4 patients had Bardet-Biedl syndrome, 1 patient had Joubert syndrome and 1 patient had Meckel Gruber syndrome phenotype. Among patients with autosomal dominant polycystic kidney disease, patients with the PKD1 gene mutation had higher creatinine levels (p value: 0.020) and no arachnoid cysts were revealed in the PKD2 group (p value: 0.014). When the domains were compared, the finding of arachnoid cyst in patients with mutations in the transmembrane domain was statistically significant (p value: 0.021). Homozygous likely pathogenic variant in the TCTN1 gene was reported in a fetus who had findings of Meckel-Gruber syndrome; microphthalmia and cardiac hypoplasia were reported as novel findings. As a conclusion, we identified variant spectrum of renal ciliopathies in Turkish cohort and revealed the association between the transmembrane domain and arachnoid cyst.

Phosphoribosylaminoimidazole carboxylase (PAICS) deficiency, caused by biallelic variants in PAICS gene, is an inborn error of de novo purine synthesis. Only two patients from a consanguineous family have been reported, with multiple congenital malformations, resulting in early neonatal death. Molecular analysis identified a homozygous p.(Lys53Arg) missense variant. We report the third case of PAICS deficiency in a 7 years old boy, presenting with polymalformative syndrome, but normal neurodevelopment. We report malformations not previously described in PAICS deficiency, notably congenital cardiopathy, and support the consistency of skeletal and oesophageal defects. Genome Sequencing identified the homozygous pathogenic variant p.(Lys53Arg), suggesting a recurrent variant in PAICS. A probable recurrence of PAICS deficiency occurred in a sibling, with a similar polymalformative syndrome antenatally diagnosed, but could not be confirmed molecularly. We further delineate the phenotype of PAICS deficiency and provide new insights concerning prognosis, notably in terms of neurodevelopment.

Biallelic loss of function variant in SEC31A is associated with lethal neurodevelopmental disorder, dysmorphic features, and skeletal defects.

Diagnostic wandering and delayed management are major issues in rare diseases. Here, we report a new Next-Generation Phenotyping (NGP) model for diagnosing Coffin Siris syndrome (CSS) on clinical photographs among controls and distinguish the different genotypes. This retrospective and prospective study, conducted from 1998 to 2023, included frontal and lateral pictures of confirmed CSS. After automatic placement of landmarks, geometric features extraction using procrustes superimposition, and textural features using a gray-level co-occurrence matrix (GLCM), we incorporated age, gender, and ethnicity and used XGboost (eXtreme Gradient Boosting) for classification. An independent validation set of confirmed CSS cases from centers in Bangalore (India) and Tbilissi (Georgia) was used. We then tested for differences between genotype groups. Finally, we introduced a new approach for generating synthetic faces of children with CSS. The training set included over 196 photographs from our center, corresponding to 58 patients (29 controls, 29 CSS). We distinguished CSS from controls in the independent validation group with an accuracy of 90.0% (73.5%-97.9%, p = 0.001). We found no facial shape difference between the different genotypes.

Hereditary spastic paraplegias (HSP) are a diverse group of neurodegenerative diseases characterized by lower limb spasticity and weakness. To date, over 80 genes have been associated with HSP, but many families remain without a molecular diagnosis. In this study, linkage analysis and whole-exome sequencing (WES) were performed to identify the causal gene in a HSP family with autosomal recessive inheritance. Multipoint linkage analysis revealed a maximum significant multipoint LOD score of 4.6 on chromosome 4. WES analysis focused on this region led to the identification of a homozygous missense variant in AIMP1 (c.223G>A). Minigene assays showed that the presumed missense variant in AIMP1 caused loss of the exon 3 donor splice site. Ultimately, this led to the use of an alternative splice site within the intron and the insertion of a premature stop codon. The identification of a novel AIMP1 causal variant contributes to the growing list of HSP genes. Furthermore, it shows that, considering also previous reported cases, disruption of AIMP1 causes a spectrum of disorders ranging from intellectual disability to more complex neurodegenerative diseases.

An in-depth analysis of susceptibility factors modifying the penetrance of rare Leber hereditary optic neuropathy-causing mutations in respiratory complex I genes encoded in mitochondrial deoxyribonucleic acid has not been performed. To bridge this gap, we conducted a review of the literature on rare mutations associated with LHON, selected those with substantial evidence of pathogenicity, and performed an in-depth analysis of the various pedigrees. Examining the influences that modify the penetrance of the classical mutations associated with this disease may offer insights into susceptibility factors in individuals carrying the rare mutations.

Broad-spectrum genetic tests often lead to the identification of variants of uncertain significance (VUS), a major issue in modern clinical genetics. A fair proportion of VUS may alter the splicing processes, but their interpretation is challenging. This study aimed at providing a classification approach for VUS potentially-affecting splicing by integrating transcript analysis from peripheral blood mRNA into routine diagnostics. VUS in DICER1, MSH2, MLH1, DYNC1H1, RPS6KA3, and SCN9A, found in patients with phenotypes compatible with the related syndromes, altered splicing, leading to their re-classification as Pathogenic/Likely Pathogenic. This had a significant clinical impact for different diseases, from hereditary tumor predisposition to neurological and congenital syndromic disorders. Transcript analysis is valuable in VUS clinical evaluation, and its incorporation into routine diagnostic workflows facilitates timely and accurate clinical decision-making.

Ataxia with Vitamin E Deficiency (AVED) is a rare autosomal recessive genetic disorder, that caused by pathogenic variants in the TTPA gene, which encodes the alpha-tocopherol transfer protein. This study investigates eight patients from three consanguineous Iranian families, using exome sequencing (ES) and Sanger sequencing to identify novel pathogenic variants in the TTPA gene. Two variants were identified: c.219T>A (p.Tyr73*) and c.205-1G>C. the first one (c.219T>A) related to potentially founder effects within regions of homozygosity. Clinical outcomes varied among patients based on vitamin E therapy initiation, with early treatment preventing severe neurological impairment. These findings improve knowledge of TTPA variants, supporting targeted genetic-based therapy. This study emphasizes the importance of genetic screening in consanguineous communities for the early detection and management of Mendelian diseases, with additional implications for managing rare genetic disorders generally.