Molecular Characterization of a Recurrent Pathogenic TYR Variant in a Consanguineous Family with Oculocutaneous Albinism Type 1

A Study on the Clinical Phenotypes and Genetic Analysis of ENG Variants in Four Hereditary Hemorrhagic Telangiectasia Type 1 Families

Background Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular disorder primarily caused by pathogenic variants in the ENG gene, leading to clinical manifestations including pulmonary arteriovenous malformation (PAVM), recurrent spontaneous nosebleeds, and other related symptoms. This study is aimed at investigating the clinical manifestations of members in four HHT1 families with PAVMs and analyze novel ENG variants. Methods Clinical evaluations, whole exome sequencing (WES), and Sanger sequencing were performed on the probands and their family members from Families 1 to 4. Bioinformatics programs were utilized to assess the pathogenicity of the candidate variants. Additionally, an in vitro minigene assay was conducted to examine the impact of the variant in Family 2 on RNA splicing, and Western blot was employed to validate the impact of the variant on protein expression and modification. Results Four ENG variants were identified: c.613del (exon 5), c.1428 + 2 T > C (intron 11), c.1498dup (exon 12), and c.322del (exon 3). The splice‐site variant c.1428 + 2 T > C, which has been reported as pathogenic in ClinVar, leads to aberrant ENG mRNA splicing with exon 11 skipping, resulting in a shorter protein (p.Lys438_Gln476del) with impaired glycosylation. Conclusion The splice‐site variant c.1428 + 2 T > C caused aberrant ENG mRNA splicing, leading to exon 11 skipping and producing a shorter protein with abnormal glycosylation (p.Lys438_Gln476del). The variants identified in Families 1, 3, and 4 (c.613delC, c.1498dupC, and c.322delG) are all frameshift variants that lead to premature termination of translation. This study expands the spectrum of ENG variants and provides insights into the pathogenesis of HHT1. These findings offer guidance for the early diagnosis for families affected by HHT1.

Case Report: Clinical and molecular genetic analysis of a patient with coexisting complete androgen insensitivity syndrome and neurofibromatosis type 1 and 15pstk + polymorphism

This is the first report of concurrent CAIS and NF1, which enriches and expands the genotypic and phenotypic spectra of both disorders.

Identification of a novel and a recurrent CDC45 variant in a Chinese family with Meier-Gorlin syndrome 7 and a literature review

A Chinese patient presenting with classic hallmarks of MGORS7 alongside atypical clinical features, including hearing and visual impairments is reported, suggesting that growth hormone therapy may be beneficial for growth retardation in patients with MGORS7.

“Severe intellectual disability with cardiac and dermatologic involvement due to homozygous METTL23 frameshift mutation: a case report of two Turkish sisters”

Homozygous Nonsense DSP Variants Selectively Affecting Desmoplakin I Cause Carvajal Syndrome in a Consanguineous Arabian Family with Four Affected Female Siblings

Introduction: Arrhythmogenic cardiomyopathy (ACM) is a myocardial disorder characterized by fibrofatty replacement of the myocardium and is associated with heart failure and sudden cardiac death. It can involve either ventricle, including left-dominant forms defined partly by genetic findings. Methods: We investigated a consanguineous family with four affected daughters presenting with ACM, epidermolytic palmoplantar keratoderma, and woolly hair. The two eldest siblings died suddenly during childhood. The remaining two affected siblings underwent genetic analysis using autozygosity mapping and whole-exome sequencing, followed by segregation analysis. Results: Autozygosity mapping identified a shared identity-by-descent (IBD) interval at the DSP locus on chromosome 6. Exome sequencing revealed a novel homozygous nonsense variant (c.4297C>T; p.Gln1433*; rs1554108283) in exon 23 of DSP. This variant introduces a premature termination codon within the region specific to transcript variant 1, sparing transcript variant 2. Both parents were heterozygous carriers. Cardiac imaging in the affected siblings demonstrated biventricular involvement, including left ventricular systolic dysfunction and right ventricular dilatation. Skin biopsy in one patient confirmed epidermolytic palmoplantar keratoderma. Conclusions: We describe a novel homozygous nonsense variant in the transcript 1-specific region of DSP causing Carvajal syndrome, characterized by severe biventricular ACM, epidermolytic palmoplantar keratoderma, and woolly hair, in a consanguineous Arabian family with four affected sisters.

Bardet-Biedl syndrome in a Chinese patient with a novel homozygous BBS5 variant from paternal uniparental disomy.

BACKGROUND Bardet-Biedl syndrome (BBS) is a rare, autosomal recessive genetic disorder with multi-systemic symptoms, including polydactyly, obesity, renal anomalies, retinal dystrophy, and cognitive impairment. Our study reported a previously unreported BBS5 homozygous variant in a Chinese patient with BBS from paternal uniparental disomy. MATERIALS AND METHODS A comprehensive ophthalmologic examination was conducted. Whole-exome sequencing and Sanger sequencing were utilized to detect pathogenic variants. Protein structure prediction and multiple sequence alignment were performed. RESULTS An 18-year-old female presented with blurry vision and night blindness since childhood. Upon conducting a general assessment, polydactyly, obesity and learning disability were also identified. Ophthalmologic examination revealed severe retinal degeneration. Whole-exome and Sanger sequencing detected a homozygous BBS5 variant (NM_152384.3: exon 3: c.185del; p.L62Wfs*16), with the homozygosity from paternal uniparental disomy. The protein structure prediction showed substantial deletions of amino acid segments caused by the variant. Multiple sequence alignment indicated that the amino acids corresponding to the variant were in a highly conserved region of the BBS5 protein, underscoring their essential role in maintaining protein function. CONCLUSIONS Our study identified a novel homozygous BBS5 variant from paternal uniparental disomy. These findings expand the genotypic and phenotypic spectrum of Bardet-Biedl syndrome.