Molecular Test Listing

Molecular Requisition

MERRF:

Myoclonus epilepsy and ragged-red fiber disease (MERRF) results from a mutation in the mitochondrial DNA and RNA. The disease is maternally inherited. The severity varies based on the segregation of a heteroplasmic (mixed mutant and wild type) mitochondrial DNA mutation. The main clinical features of MERRF are myoclonus, myoclonic epilepsy, ataxia (jerky gait) and muscle tissue with ragged-red fibers. Seizures, dementia and optic atrophy can also be present.

Due to the dosage effects as a result of heteroplasmy (varying mixture of mutant and normal mitochondrial DNA), all these conditions can appear in families with no apparent past history and appear unevenly between siblings. The mutation can also arise spontaneously. An A8344G mutation is responsible for 85 - 95% of the identified cases of MERRF. This mutation has also been found to contribute to cases of Leigh’s syndrome, myoclonus, and proximal myopathy.

• Individuals with unexplained epileptic episodes or ataxia.
• To disriminate between MERRFand 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 NARP 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: