Title: Warburg Micro Syndrome 1 due to Segmental Paternal Uniparental Isodisomy of Chromosome 2 Detected by Whole-Exome Sequencing and Homozygosity Mapping
Abstract: Warburg micro syndrome (WARBM) is a rare autosomal recessive disorder characterized by microcephaly, cortical dysplasia, intellectual disability, ocular abnormalities, spastic diplegia, and microgenitalia. WARBM has 4 subtypes arising from pathogenic variants in 4 genes (RAB18, RAB3GAP1, RAB3GAP2, and TBC1D20). Here, we report on a patient with a homozygous pathogenic c.665delC (p.Pro222HisfsTer30) variant in the RAB3GAP1 gene identified by whole-exome sequencing (WES) analyses. Only his father was a heterozygous carrier, and homozygosity mapping analysis of the WES data revealed large loss-of-heterozygosity regions in both arms of chromosome 2, interpreted as uniparental isodisomy. This uniparental disomy pattern could be due to paternal meiosis I nondisjunction because of the preserved heterozygosity in the pericentromeric region. This report provides novel insights, including a rare form of UPD, usage of homozygosity mapping analysis for the evaluation of isodisomy, and the first reported case of WARBM1 as a result of uniparental isodisomy.
Publication Year: 2020
Publication Date: 2020-01-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 3
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