Dataset Information

Linkage to chromosome 2q36.1 in autosomal dominant Dandy-Walker malformation with occipital cephalocele and evidence for genetic heterogeneity.

ABSTRACT: We previously reported a Vietnamese-American family with isolated autosomal dominant occipital cephalocele. Upon further neuroimaging studies, we have recharacterized this condition as autosomal dominant Dandy-Walker with occipital cephalocele (ADDWOC). A similar ADDWOC family from Brazil was also recently described. To determine the genetic etiology of ADDWOC, we performed genome-wide linkage analysis on members of the Vietnamese-American and Brazilian pedigrees. Linkage analysis of the Vietnamese-American family identified the ADDWOC causative locus on chromosome 2q36.1 with a multipoint parametric LOD score of 3.3, while haplotype analysis refined the locus to 1.1 Mb. Sequencing of the five known genes in this locus did not identify any protein-altering mutations. However, a terminal deletion of chromosome 2 in a patient with an isolated case of Dandy-Walker malformation also encompassed the 2q36.1 chromosomal region. The Brazilian pedigree did not show linkage to this 2q36.1 region. Taken together, these results demonstrate a locus for ADDWOC on 2q36.1 and also suggest locus heterogeneity for ADDWOC.

SUBMITTER: Jalali A

PROVIDER: S-EPMC2822644 | biostudies-literature | 2008 Apr

REPOSITORIES: biostudies-literature

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Linkage to chromosome 2q36.1 in autosomal dominant Dandy-Walker malformation with occipital cephalocele and evidence for genetic heterogeneity.

Jalali Ali A Aldinger Kimberly A KA Chary Ajit A McLone David G DG Bowman Robin M RM Le Luan Cong LC Jardine Phillip P Newbury-Ecob Ruth R Mallick Andrew A Jafari Nadereh N Russell Eric J EJ Curran John J Nguyen Pam P Ouahchi Karim K Lee Charles C Dobyns William B WB Millen Kathleen J KJ Pina-Neto Joao M JM Kessler John A JA Bassuk Alexander G AG

Human genetics 20080119 3

We previously reported a Vietnamese-American family with isolated autosomal dominant occipital cephalocele. Upon further neuroimaging studies, we have recharacterized this condition as autosomal dominant Dandy-Walker with occipital cephalocele (ADDWOC). A similar ADDWOC family from Brazil was also recently described. To determine the genetic etiology of ADDWOC, we performed genome-wide linkage analysis on members of the Vietnamese-American and Brazilian pedigrees. Linkage analysis of the Vietnam ...[more]

PMID: 18204864

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Project description:BackgroundChromosome 16p11.2 deletions and duplications were found to be the second most common copy number variation (CNV) reported in cases with clinical presentation suggestive of chromosomal syndromes. Chromosome 16p11.2 deletion syndrome shows remarkable phenotypic heterogeneity with a wide variability of presentation extending from normal development and cognition to severe phenotypes. The clinical spectrum ranges from neurocognitive and global developmental delay (GDD), intellectual disability, and language defects (dysarthria /apraxia) to neuropsychiatric and autism spectrum disorders. Other presentations include dysmorphic features, congenital malformations, insulin resistance, and a tendency for obesity. Our study aims to narrow the gap of knowledge in Saudi Arabia and the Middle Eastern and Northern African (MENA) region about genetic disorders, particularly CNV-associated disorders. Despite their rarity, genetic studies in the MENA region revealed high potential with remarkable genetic and phenotypic novelty.ResultsWe identified a heterozygous de novo recurrent proximal chromosome 16p11.2 microdeletion by microarray (arr[GRCh38]16p11.2(29555974_30166595)x1) [(arr[GRCh37]16p11.2(29567295_30177916)x1)] and confirmed by whole exome sequencing (arr[GRCh37]16p11.2(29635211_30199850)x1). We report a Saudi girl with severe motor and cognitive disability, myoclonic epilepsy, deafness, and visual impairment carrying the above-described deletion. Our study broadens the known phenotypic spectrum associated with recurrent proximal 16p11.2 microdeletion syndrome to include developmental dysplasia of the hip, optic atrophy, and a flat retina. Notably, the patient exhibited a rare combination of microcephaly, features consistent with the Dandy-Walker spectrum, and a thin corpus callosum (TCC), which are extremely infrequent presentations in patients with the 16p11.2 microdeletion. Additionally, the patient displayed areas of skin and hair hypopigmentation, attributed to a homozygous hypomorphic allele in the TYR gene.ConclusionThis report expands on the clinical phenotype associated with proximal 16p11.2 microdeletion syndrome, highlighting the potential of genetic research in Saudi Arabia and the MENA region. It underscores the importance of similar future studies.

Dataset Information

Linkage to chromosome 2q36.1 in autosomal dominant Dandy-Walker malformation with occipital cephalocele and evidence for genetic heterogeneity.

Publications

Linkage to chromosome 2q36.1 in autosomal dominant Dandy-Walker malformation with occipital cephalocele and evidence for genetic heterogeneity.

Similar Datasets

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