DSG2 Mutation Analysis
Desmoglein 2, encoded by DSG2 gene, is a calcium-binding transmembrane glycoprotein component of desmosomes in vertebrate epithelial cells. Desmosomes are cell-cell junctions between epithelial, myocardial, and certain other cell types. Three desmoglein subfamily members have been identified so far and all are members of the cadherin cell adhesion molecule superfamily. These desmoglein family members are located in a cluster on chromosome 18. DSG2 is expressed in colon, colon carcinoma, and other simple and stratified epithelial-derived cell lines. DSG2 gene contains 15 exons and spans around 50 kb genomic distance that was mapped to chromosome 18q12.1. Mutations in DSG2 gene have been associated with familial arrhythmogenic right ventricular dysplasia/cardiomyopathy type 10 (ARVD/C10). ARVD/C is an autosomal dominant disease characterized by partial degeneration of the myocardium of the right ventricle, electrical instability and sudden death. DSG2 mutations demonstrate autosomal dominant inheritance with a broad range of clinical severity both within and between families. Definitive genotype/phenotype correlations have not been described.
The John Welsh Cardiovascular Diagnostic Laboratory offers molecular genetic testing for DSG2 mutations. Individuals are tested by automatic fluorescent DNA sequencing of the coding exons of the DSG2 gene. We strongly recommend initial testing of a clearly affected individual, if available, in order to provide the greatest test sensitivity and clearest interpretation of results for subsequent family members. Genetic counseling is recommended for all individuals.
Reasons for Referral
Molecular confirmation of the diagnosis of familial arrhythmogenic right ventricular dysplasia/cardiomyopathy type 10 (ARVD/C10).
Genomic DNA is analyzed for DSG2 mutations by automatic fluorescent DNA sequencing of the coding exons of the DSG2 gene, as well as the exon/intron junctions and a portion of the 5' and 3' untranslated regions. Patient DNA is sequenced in both the forward and reverse orientations. If a mutation is identified, additional family members are analyzed only for the familial mutation by automatic fluorescent DNA sequencing.
|Service||Direct and Institutional Billing||CPT Codes|
|Index Case (Full Gene)||$1200 per sample||81406, G0452|
|Additional Family Members||$300 per sample; known familial mutation only||81403, G0452|
DNA Sequencing Analysis: Approximately 99 percent detection of mutations in coding exons 1-15 of DSG2.
Blood (preferred): EDTA (purple-top) tubes: Adult: 5 cc, Child: 5 cc, Infant: 2-3 cc
Tissue: Frozen (preferred), RNAlater, Formalin-fixed, Paraffin-embedded
Other Body Fluids: Call to inquire
Buccal Swabs: One swab from each cheek