Dentatorubral-Palladoluysian Atrophy


Molecular Genetics Clinical Laboratory- Dentatorubral-Palladoluysian Atrophy

INDICATIONS FOR TESTING:
The clinical features of Dentatorubral-Palladolusian Atrophy (DRPLA, Haw River Syndrome) include ataxia, choreoathetosis, dementia, and psychiatric disturbance changes in adult patients. In addition, myoclonus, seizures, epilepsy, and progressive intellectual deterioration is seen in patients under the age of 20 years. The clinical presentation is extremely variable. This disorder is autosomal dominant and may be characterized by markedly increased severity in sucessive generations, a phenomenon known as genetic anticipation. DRPLA is caused by expansion of an unstable trinucleotide (CAG) repeat in the first exon of the DRPLA gene in the chromosomal region 12p13.

TESTING OFFERED:
The majority (~100%) of affected individuals have the CAG repeat expansion in the DRPLA gene that is readily detected. This repeat is polymorphic, with 6 to 35 repeats found in unaffected individuals, and from 49 to 88 repeats in affected individuals. There is an inverse correlation of repeat length with disease severity.

TURN-AROUND TIME:
Most testing is completed within a time of 21 days following specimen receipt. Prenatal testing is usually completed within 7 days from specimen receipt.

SPECIMEN REQUIREMENTS:
All specimens should be kept at room temperature and shipped overnight in an insulated container.

Adults and Children:
A tube of 4 cc whole blood collected in an EDTA (lavender top) tube is preferred. Whole blood collected with other anticoagulants is acceptable but not preferred.

Neonates:
The minimum specimen is 0.5 cc whole blood in EDTA tube.

Prenatal:
Amniocentesis: 15 cc whole amniotic fluid submitted without culture. A backup culture should be arranged but is rarely required.
CVS: a single whole villus, dissected free of decidua.

COST:
The cost of testing is available upon request.

FOR MORE INFORMATION, PLEASE CONTACT:
Phone: (727) 767-8985 (Laboratory)
            (727) 767-8611 (Director)
Fax: (727) 767-8367
E-mail: muellert@allkids.org