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Pediatrics - Cardiology

Houston, Texas

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Pediatrics - Cardiology
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EMD Mutation Analysis

Emerin is an inner nuclear membrane protein that is expressed in cardiac, skeletal and smooth muscle. Multiple functions for emerin, including the stabilization of the nuclear membrane during muscle contraction and organizational maintenance of the nuclear membrane during cell division, have been proposed. Emerin is encoded by the gene EMD (STA), which is composed of six exons and is located at Xq28.

Cytoskeleton of the Cardiomyocyte

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Mutations in EMD have been identified in males with X-linked recessive Emery-Dreifuss muscular dystrophy, which is characterized by early contractures of the Achilles tendons, elbows, and post-cervical muscles with humero-peroneal weakness and muscle wasting. Affected individuals also have cardiac conduction defects and may have a generalized cardiomyopathy. X-linked recessive EMD mutations identified in affected individuals include missense, nonsense, splicing, small deletion or insertion, and larger genomic DNA deletion mutations.

The John Welsh Cardiovascular Diagnostic Laboratory offers molecular genetic testing for EMD mutations. Symptomatic males are tested by automatic fluorescent DNA sequencing of all six exons of the EMD gene. We strongly recommend initial testing of an affected male, if available, in order to provide the greatest test sensitivity and clearest interpretation of results for subsequent carrier female testing. If an affected male is unavailable for testing, testing of females at high risk is offered. Genetic counseling is recommended for all individuals in order to identify additional at-risk family members and to discuss reproductive issues.

Reasons for Referral

  • Molecular confirmation of the diagnosis of Emery-Dreifuss muscular dystrophy in males
  • Carrier testing in females with a family history of Emery-Dreifuss muscular dystrophy in males
  • Carrier testing is not offered for asymptomatic minor females. Please call for additional information.

Methodology

Genomic DNA is analyzed for EMD mutations by automatic fluorescent DNA sequencing of all six exons of the EMD 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 Fees

Service Direct and Institutional Billing CPT Codes
Index Case (Male or Female) $450 per sample 81405, G0452
Additional Family Members $300 per sample; known familial mutation only 81403, G0452

Sensitivity

  • Males - DNA Sequencing Analysis: Approximately 97.5 percent detection of mutations in exons 1-6 of EMD
  • Females - DNA Sequencing Analysis: Approximately 93.5 percent detection of mutations in exons 1-6 of EMD

Specimen Requirements

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

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