Neurogenetic muscle weakness, ataxia, retinitis pigmentosa (NARP) results from a mutation in the mitochondrial DNA of the cell. Symptoms of NARP are developmental delay, retinituis pigmentosa, dementia, seizures, ataxia and proximal muscle weakness. 

A mutation (T to G substitution) at position 8993 (subunit 6 of the ATP synthase gene) is responsible for approximately 85% of the identified cases of NARP. This mutation has also been found to contribute to 25% of cases of Leigh’s syndrome which results myoclonus, and proximal myopathy. Due to the dosage effects as a result of heteroplasmy (varying mixture of mutant and normal mitochondrial DNA), NARP can appear in families with no apparent past history, and symptoms can appear unevenly between siblings.

• Individuals with unexplained epileptic episodes.
• To disriminate between NARP or Leigh Syndrome and other mitochondrial diseases in an affected individual.
• To accurately predict the risk of having a child with the condition.

• This testing may be combined with testing for MERRF and MELAS in a Mitochondrial Panel.

• PCR amplification of the region including the A8344G mutation in the mitochondrial DNA, followed by mutation specific restriction enzyme digestion.

• Blood EDTA (purple top) tubes:  

            Newborn: minimum 1-2 mL          

            Child/Adult: prefer 2 tubes of 3-5 mL

• Prenatal testing: Please contact the laboratory for instructions.

TURNAROUND TIME:     8 working days

CPT CODES: