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Diagnostic Services

Genetics Lab


POLG1-Related Disorders

DNA polymerase gamma is the only DNA polymerase found in the mitochondria and is responsible for mtDNA replication and repair. Mutations in the gene encoding polymerase gamma, POLG1, cause mtDNA depletion or multiple mtDNA deletions resulting in highly heterogeneous group of mitochondrial diseases. POLG1 mutations may account for up to 25% of all adult onset mitochondrial disease. POLG1 mutations have been described in Progressive External Ophthalmoplegia both autosomal dominant and recessive forms, parkinsonism and premature menopause, adult onset cerebellar ataxia, Sensory Ataxia Neuropathy with Opthalmoparesis (SANDO), Alpers Syndrome (childhood onset progressive spastic quadriparesis, progressive cerebral degeneration and liver failure) and other childhood or adulthood onset ataxia syndromes with and without seizures.

Test Name: Polymerase Gamma 1 Sequencing Analysis
Test Code:
Test Description:
Polymerase Chain Reaction (PCR) followed by sequence analysis of the entire coding region (20 exons) of the POLG1 gene.
POLG, POLG1, Sando, Alpers
POLG1 DNA sequencing is appropriate for individuals with any of the following:
• Progressive external opthalmoplegia
• Cerebellar ataxia +/- seizures
• Acute liver failure
• Multiple mtDNA deletions or mtDNA depletion in affected tissues
• Cytochrome oxidase (COX)-deficient muscle fibers
Related Tests:
Clinical Links:
Mon - Fri
Turnaround Time:
2-3 weeks
PCR followed by DNA sequencing
Reference Range:
Interpretive report will be provided
Consent Form:
Sample Requirements: Type
Whole blood: 1-3 mL in EDTA (purple top) or ACD (yellow top).
DNA: 5 micrograms extracted DNA.

Do not spin. Refrigerate blood samples which will not be immediately shipped.

Room temperature via overnight shipping.
Samples Received:
Monday - Friday 8am - 5pm PST
Special Considerations:
Please e-mail Lab Client Services ( or call at 206-987-2617 with any billing questions
CPT Code:
Please e-mail Lab Client Services ( or call at 206-987-2617 with any billing questions