Description:

The ADP/ATP translocator, or adenine nucleotide translocator (ANT), is the most abundant mitochondrial protein. In its functional state, it is a homodimer of 30-kD subunits embedded asymmetrically in the inner mitochondrial membrane. The dimer forms a gated pore through which ADP is moved from the matrix into the cytoplasm. Dominant missense mutations in the heart and skeletal muscle-specific isoform of the ANT1 gene cause autosomal dominant progressive external ophthalmoplegia (ad-PEO). Affected patients accumulate multiple mitochondrial DNA deletions in muscle. Recently, autosomal recessive ANT1 mutations have been identified in patients with hypertrophic cardiomyopathy, mild myopathy with exercise intolerance and lactic acidosis but no ophthalmoplegia. ANT1 is a mitochondrial solute carrier SLC25A4. The ANT1 gene contains 4 exons and is located on chromosome 4q35.

Reasons for Referral:

• Confirmation of a clinical diagnosis
• Carrier testing

Testing Methodology:

A PCR-based assay is used to amplify all exons and the immediately adjacent intronic regions of the ANT1 gene. Direct sequence analysis of PCR products is performed in both the forward and reverse directions using automated fluorescent dideoxy sequencing methods.

Specimen Requirements:

Blood: EDTA (purple-top) tubes: Adult: 14 cc; Child: 6 cc; Infant: 2-3 cc

Turnaround Time:

Index: 4 weeks
Known Familial Mutation: 2 weeks

CPT Codes and Prices:

Index: 83904x8, 83898x4, 83912, 83891, 83894x2
Known Familial Mutation: 83904x4, 83898x2, 83912, 83891, 83894x2

Shipping Information

Forms:

>> Gene Sequencing Requisition or Mitochondrial Requisition - Mitochondrial Diagnostic Checklist is included
>> Prenatal Requisition

References:

1. Palmieri L et al. (2005) Complete loss-of-function of the heart/muscle-specific adenine nucleotide translocator is associated with mitochondrial myopathy and cardiomyopathy. Hum. Mol. Genet. 14: 3079-3088.
2. Agostino A et al. (2003) Mutations of ANT1, Twinkle, and POLG1 in sporadic progressive external ophthalmoplegia (PEO). Neurology 60: 1354-1356.
3. Napoli L et al. (2001) A novel missense adenine nucleotide translocator-1 gene mutation in a Greek adPEO family. Neurology 57: 2295-2298.

Test Codes:

Index: 3170
Known Familial Mutation: 3171
Prenatal: 3172

Medical Genetics Laboratories
Baylor College of Medicine · Houston, TX 77030
Phone: 1-800-411-GENE · Fax: 713-798-6584
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