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Felix Boschann

Publications and source records attributed to Felix Boschann.

3 recordsLinked to original sources

Identification of biallelic loss-of-function PREP variants in three individuals with syndromic intellectual disability.

BACKGROUND: Neurodevelopmental disorders are one of the most prevalent reasons for genetic testing in childhood. Despite the identification of over 1950 associated genes, many proposed candidate genes lack convincing gene-disease validity. The gene PREP encodes the broadly expressed prolyl endopeptidase whose exact function remains largely unknown. A homozygous PREP variant has been reported once as a candidate gene in two siblings with intellectual disability but no functional studies were conducted. METHODS: Exome and trio genome sequencing were performed in two unrelated families as part of larger cohorts. Segregation analysis, RNA sequencing and immunoblots were performed to further examine the pathogenicity of detected PREP variants. RESULTS: We report three individuals from two unrelated families who presented with intellectual disability, behavioural abnormalities, strabismus, generalised muscular hypotonia, dysmorphic facial features and epilepsy. Exome and genome sequencing identified two different homozygous rare PREP variants: c.1570_1573dup, p.(Asn525Thrfs*5) and c.1839-2A>G, p.?. RNA sequencing confirmed the detected intronic variant to result in two aberrant mRNA isoforms. In patient-derived cells immunoblots showed absence of PREP protein. CONCLUSION: Our data suggest PREP deficiency as the underlying cause of a syndromic neurodevelopmental disorder.

Female

Hemizygous loss-of-function variants of EIF1AX are associated with a syndromic neurodevelopmental disorder.

Pathogenic variants of genes encoding initiation factors can cause neurological diseases, including neurodevelopmental disorders and brain abnormalities. The eukaryotic translation initiation factor 1 A, X-linked (EIF1AX) is a gene located at Xp22.12 that plays an important role in the regulation of translation initiation. Here, we identified de novo hemizygous EIF1AX variants in male individuals with neurodevelopmental disorders and explored their possible involvement in these neurological disorders. We performed trio-based exome or whole genome sequencing in four families. The pathogenicity of EIF1AX variants was evaluated using a molecular dynamic simulation and transgenic Drosophila models. We identified four de novo hemizygous EIF1AX variants in four male individuals with variable neurodevelopmental delay, dysmorphic features, behavioral problems, ophthalmological abnormalities, and structural abnormalities in the brain. One variant was predicted to cause a splicing alteration, and minigene analysis confirmed exon skipping leading to the generation of a premature termination codon. In transgenic Drosophila harboring wild-type (WT) EIF1AX or the three other EIF1AX missense variants, overexpression of WT and the p.(Asn17Asp) variant caused structural abnormalities in the compound eye, whereas the p.(Lys64Glu) and p.(Asp90Gly) variants significantly reduced these eye abnormalities. In addition, WT overexpression resulted in significant axonal toxicity in the Drosophila optic nerve, causing a significant reduction in the number of axons, whereas all mutants showed only a mild reduction in axonal number. Our findings indicated that all variants resulted in different degrees of EIF1AX loss-of-function. Overall, EIF1AX is a novel gene for which loss-of-function variants appear to produce syndromic neurodevelopmental disorders in males.

Humans