NPJ Genomic Medicine最新文献

Senior-Løken syndrome is a rare ciliopathy characterized by retinal dystrophy and nephronophthisis. This autosomal recessive inherited disease is caused by pathogenic variants in several genes, including IQCB1. We present a Senior-Løken case that remained genetically unexplained after routine genetic testing, including exome and genome sequencing. To identify the genetic cause for this individual, a combination of innovative long-read technologies was employed. Using optical genome mapping, an intronic 6.2-kb insertion in IQCB1 was revealed. Validation by long-read genome sequencing determined that this insertion consisted of a LINE-1/ERV1-mobile element. The variant was found in trans with a pathogenic IQCB1 2-bp deletion previously identified by exome sequencing. To investigate the consequences of the insertion, targeted long-read RNA-sequencing was performed, revealing a complex splice defect causing the introduction of a premature stop codon. This finding suggests that mobile element insertions represent a yet underestimated variant type that is difficult to detect using short-read sequencing.

Ciliopathies are associated with a range of phenotypes including retinal degeneration and skeletal abnormalities. We present a retrospective study of 49 patients with variants in Cilia and Flagella Associated Protein 410 (CFAP410) from multiple ophthalmic centers across the world. Common clinical features included early-onset reduced visual acuity, photophobia, and delayed light-to-dark adaptation. A cone-rod dystrophy pattern was observed roughly two times more commonly than rod-cone dystrophy. A minority of patients (22.4%) presented with skeletal abnormalities consistent with axial spondylometaphyseal dysplasia (SMDAX). Patients with the most severe ophthalmic and skeletal phenotypes had disease-associated variants within conserved leucine-rich regions of CFAP410, and the structural effects of these variants were modelled using ChimeraX. This report furthers our understanding of CFAP410-associated clinical phenotypes such as retinal dystrophy and skeletal dysplasia.

Inherited retinal diseases (IRDs) are a group of rare Mendelian disorders that often result in progressive vision loss and potentially to complete blindness at the end stage. In this study, we investigated a large cohort of patients with IRDs from Pakistan, the world's fifth most populous country, which is also characterized by distinctive demographic features, such as a high prevalence of consanguinity, endogamy, and a wide variety of ethnic groups. Specifically, we examined a total of 213 unrelated families (722 affected individuals) from three very large geographical regions. We achieved precise molecular diagnosis in 171 pedigrees (80.3%) and detected causative variants in 60 different IRD-associated genes, revealing a mutational landscape that differed substantially from previous data from other European or Asian populations, heavily shaped by endogamy and rare or recurrent founder mutational events. To our knowledge, this work represents the largest genetic study on IRDs within the Pakistani population.

Familial adenomatous polyposis (FAP) is caused by pathogenic germline variants in the tumor suppressor gene APC. Confirmation of diagnosis was not achieved by cancer gene panel and exome sequencing or custom array-CGH in a family with suspected FAP across five generations. Long-read genome sequencing (PacBio), short-read genome sequencing (Illumina), short-read RNA sequencing, and further validations were performed in different tissues of multiple family members. Long-read genome sequencing resolved a 6 kb full-length intronic insertion of a heterozygous LINE-1 element between exons 7 and 8 of APC that could be detected but not fully resolved by short-read genome sequencing. Targeted RNA analysis revealed aberrant splicing resulting in the formation of a pseudo-exon with a premature stop codon. The variant segregated with the phenotype in several family members allowing its evaluation as likely pathogenic. This study supports the utility of long-read DNA sequencing and complementary RNA approaches to tackle unsolved cases of hereditary disease.

Individuals affected by a rare disease often experience a long and arduous diagnostic odyssey. Delivery of genetic answers in a timely manner is critical to affected individuals and their families. Multi-omics, a term which usually encompasses genomics, transcriptomics, proteomics, metabolomics and lipidomics, has gained increasing popularity in rare disease research and diagnosis over the past decade. Mass spectrometry (MS) is a technique allowing the study of proteins, metabolites and lipids and their fragments at scale, enabling researchers to effectively determine the presence and abundance of thousands of molecules in a single test, accurately quantify their specific levels, identify potential therapeutic biomarkers, detect differentially expressed proteins in patients with rare diseases, and monitor disease progression and treatment response. In this review, we focus on mass spectrometry (MS)-based omics and survey the literature describing the utility of different MS-based omics and how they have transformed rare disease research and diagnosis.

In patients with complex congenital heart disease (CHD) pathogenic SMAD6 variants have been described previously. The aim of this study was to analyze if pathogenic SMAD6 variants also occur in patients with CHD associated with pulmonary arterial hypertension (CHD-APAH) or idiopathic PAH. A PAH gene panel with up to 64 genes including SMAD6 was used to sequence 311 patients with idiopathic PAH (IPAH) and 32 with CHD-APAH. In 4 of 32 (12.5%) CHD-APAH and in 2 out of 311 (0.64%) IPAH patients we identified likely pathogenic or rare SMAD6 missense variants. All CHD-APAH patients with a rare SMAD6 variant had complex CHD. One patient had bi-allelic SMAD6 variants, combined pulmonary valve defect and supravalvular aortic stenosis, craniosynostosis and radioulnar synostosis. This is the first description of potentially disease-causing SMAD6 variants in patients with IPAH and complex CHD-APAH. Further studies are needed to assess pathogenesis and prevalence of pathogenic SMAD6 variants in PAH.

Rapid genomic diagnostics in the Neonatal Intensive Care Unit represents a paradigm shift in medicine with increasing evidence of the utility of early diagnosis, impacting management. The goal of the Utah NeoSeq Project was to implement and evaluate a multidisciplinary and longitudinal rapid sequencing program while transitioning to CLIA-certified sequencing. Enrollment of 65 infants resulted in 26 (40%) with a diagnostic variant(s) and 7 (11%) harboring a strong candidate. This includes re-analyses resulting in four additional diagnoses. Parental surveys indicated that 7% (4/59) of parents had a decisional conflict after consent, and 3% (2/59) experienced decisional regret after the results. Fifty-two provider surveys were conducted. Seventy-nine percent (41/52) of results and 86% (19/22) of diagnostic results were "very useful" or "useful" and associated with management changes. The NeoSeq Project demonstrates that a multidisciplinary collaborative approach to diagnosis is feasible. We have developed a generalizable, collaborative protocol that addresses the need for expedited genetic evaluation with emerging technologies.

Individuals with heritable thoracic aortic disease (HTAD) face a high risk of deadly aortic dissections, but genetic testing identifies causative variants in only a minority of cases. We explored the contribution of non-canonical splice variants (NCVAS) to thoracic aortic disease (TAD) using SpliceAI and sequencing data from diverse cohorts, including 551 early-onset sporadic dissection cases and 437 HTAD probands with exome sequencing, 57 HTAD pedigrees with whole genome sequencing, and select sporadic cases with clinical panel testing. NCVAS were identified in syndromic HTAD genes such as FBN1, SMAD3, and COL3A1, including intronic variants in FBN1 in two Marfan syndrome (MFS) families. Validation in the Penn Medicine BioBank and UK Biobank showed enrichment of NCVAS in HTAD-associated genes among dissections. These findings suggest NCVAS are an underrecognized contributor to TAD, particularly in sporadic dissection and unsolved MFS cases, highlighting the potential of advanced splice prediction tools in genetic diagnostics.