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Pediatrics - Cardiology

Houston, Texas

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Pediatrics - Cardiology
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KCNA5 Mutation Analysis

The KCNA5 gene encodes the potassium voltage-gated ion channel, shaker-related subfamily, member 5 protein (KCNA5), also known as Kv1.5. This member contains six membrane-spanning domains with a shaker-type repeat in the fourth segment. It belongs to the delayed rectifier class, the function of which could restore the resting membrane potential of beta cells after depolarization and thereby contribute to the regulation of insulin secretion. This gene consists of 1 exon and spans about 2.8 kb of genomic distance that has been mapped to 12p13.32. Mutations in KCNA5 gene are associated with familial atrial fibrillation type 7 and pulmonary arterial hypertension (PAH). KCNA5 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 KCNA5 mutations. Individuals are tested by automatic fluorescent DNA sequencing of the coding exons of the KCNA5 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 pulmonary arterial hypertension (PAH) and familial atrial fibrillation type 7.

Methodology

Genomic DNA is analyzed for KCNA5 mutations by automatic fluorescent DNA sequencing of the coding exons of the KCNA5 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 (Full Gene) $500 per sample 81403, G0452
Additional Family Members $300 per sample; known familial mutation only 81403, G0452

Sensitivity

DNA Sequencing Analysis: Approximately 99 percent detection of mutations in coding exon 1 of KCNA5.

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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