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Pediatrics - Cardiology

Houston, Texas

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Pediatrics - Cardiology
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GPD1L Mutation Analysis

GPD1L gene encodes the protein that catalyzes the conversion of sn-glycerol 3-phosphate to glycerone phosphate. This gene contains eight exons spanning 63 kb of genomic distance that has been mapped to chromosome 3p25-p22. The protein encoded by this gene is found in the cytoplasm, associated with the plasma membrane, where it binds the sodium channel, voltage-gated, type V, alpha subunit (SCN5A) and plays a role in regulating cardiac sodium current. Defects in this gene cause Brugada syndrome type 2 (BRS2) and sudden infant death syndrome (SIDS). GPD1L mutations demonstrate autosomal dominant inheritance with a broad range of clinical severity both within and between families.

The John Welsh Cardiovascular Diagnostic Laboratory offers molecular genetic testing for GPD1L mutations. Individuals are tested by automatic fluorescent DNA sequencing of the coding exons of the GPD1L 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 Brugada syndrome type 2 (BRS2) as well as sudden infant death syndrome (SIDS).


Genomic DNA is analyzed for GPD1L mutations by automatic fluorescent DNA sequencing of the coding exons of the GPD1L 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) $800 per sample 81405, 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 1-8 of GPD1L.

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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