PubMed HealthSearch

Biomedical subjects

German Demidov

Publications and source records attributed to German Demidov.

2 recordsLinked to original sources

Biallelic RDH11 variants cause syndromic retinitis pigmentosa with early-onset cataracts and neurodevelopmental delay: a multicenter case series.

Biallelic variants in the RDH11 gene, a retinol dehydrogenase involved in the visual cycle and systemic retinoid homeostasis, were initially implicated in a rare condition characterized by retinal dystrophy, early-onset cataract, neurodevelopmental anomalies and myopathy, through single-family reports, with this association more recently being confirmed in a larger study. Here, we further establish the pathogenic role of RDH11 by presenting a large multi-center cohort, comprising eight individuals from seven unrelated families. Comprehensive genetic analysis identified homozygous variants in all affected subjects, including two novel variants, strongly supporting loss-of-function as the primary disease mechanism. Detailed clinical phenotyping defined a consistent and severe multisystem disorder. Ophthalmologically, the hallmark features include bilateral congenital or early-childhood cataracts requiring surgical intervention, accompanied by retinitis pigmentosa (RP). In terms of extra-ocular involvement, the cohort exhibited a high prevalence of neurodevelopmental delay, including intellectual disability, autistic spectrum disorder and learning difficulties. These features were frequently accompanied by congenital microcephaly, intrauterine and postnatal growth restriction, facial dysmorphisms, and dental anomalies. By significantly expanding both the mutational and phenotypic spectrum of RDH11-related disease, our findings provide independent replication of this gene-disease association and definitively support RDH11 as a bona fide syndromic RP gene.

Journal Article

The burden of TTN variants in the genomic era: Analysis of 18,462 individuals from the Solve-RD consortium and general recommendations.

PURPOSE: Titin, the largest protein in the human body, has been associated with several disease phenotypes caused by variants in the TTN gene. With around 20% of the population carrying a rare TTN variant and over 60 million genomes expected to have been sequenced worldwide by 2025, interpreting these findings presents major challenges. This study analyzed TTN variants in the Solve-RD cohort, the European network for unsolved rare disease cases. METHODS: We collected data from 11,072 individuals with suspected rare diseases and 7390 healthy relatives from the Solve-RD consortium, checking and manually reviewing TTN variants. We then used a filtering approach focused on clinical relevance, and we provided updated recommendations based on recent literature. RESULTS: Among the cohort, 240 individuals (1.3%) carried at least one heterozygous TTN truncating variant (TTNtv), with a 3.8% prevalence in the neuromuscular subgroup, primarily composed of unsolved cases. Four individuals received a titinopathy diagnosis. Additionally, 99 participants (0.5%) had a TTNtv in a high cardiac percent spliced in exon (>80%), and 4 had an overt cardiomyopathy. CONCLUSION: This study highlights the need for standardized approach to TTN variants, and investigation of missing heritability in individuals with skeletal myopathy with het TTNtv. Establishing consensus on percent spliced in-based thresholds will be essential for assessing cardiac risk and guiding the management of asymptomatic individuals.

Humans