Friedreich ataxia (FRDA), the most common form of inherited ataxia, is a degenerative disease characterized by progressive ataxia (weakness and unsteadiness)  in the gait and limbs. There is also a loss of tendon reflexes in the legs, dysarthria and loss of position sense. Many patients have a cardiomyopathy and, in a small portion of the patients, diabetes or carbohydrate intolerance can be detected. Onset of symptoms commonly occurs around puberty and almost always before age 25. 

FRDA is a recessive disease with a prevalence of 1 in 50,000 and a carrier frequency of 1 in 120 in Caucasians. The principle disease-causing mutation (95%) in the frataxin gene (9q13-q21.1) is an expansion of a GAA repeat in the intron from its normal range of 5-25 repeats to between 50 and 1500 repeats in affected individuals.  The expanded size is unstable and can enlarge or contract during transmission between parent and child. However, the recessive nature of FRDA contrasts to other diseases caused by expansions of trinucleotide repeats.

• To determine whether a child with progressive ataxia may have FRDA.
• To discriminate between early FRDA and other neurological conditions.
• To evaluate the risk of a couple having a child with FRDA.  

• For ambiguous patients, this test may be ordered as part of the Neurological Panel.

• Fluorescent PCR sizing of the GAA region of the frataxin gene.

• 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:     10 working days

CPT CODES: