Huntington Disease Direct Mutation DNA Diagnostic Test
- OHSU Service Code:
- 102-8844
- Lab Section:
- Molecular Diagnostic Center
- Synonyms:
- HD
- Test Schedule:
- Weekly. Result turnaround in 2 weeks.
- Specimen
Requirements: - 6.0 mL whole blood in EDTA vacutainer tube. For requisition slips.
An ordering physician statement must accompany all requests for testing.
- Reference Range:
- PCR-based testing measures the number of CAG trinucleotide repeats in the HD gene.
Reference Range #CAG Repeat
Normal 10-26
Indeterminate 27-35
Mutant-Indeterminate Clinical
Phenotype 36-39
Mutant-Clinically affected or
likely to be symptomatic in future <=40 - Interpretation:
- 10-26: No clinical phenotype
27-35: Indeterminate - Further studies may be indicated. Contact laboratory director at 503-494-5400.
36-39: Mutant Allele-Indeterminate clinical pheotype. Symptoms may not appear in patient's lifetime. Contact the laboratory director at 503-494-5400.
<=40: Clinically affected or likely to become symptomatic in the future. - Comments:
- Testing is diagnostic for normal/presymptomatic/disease states. Huntington disease is an autosomal dominant disease with onset in adult life in most cases. Extensive experience with affected individuals and their families has indicated that it is mandatory for individuals requesting presymptomatic testing to participate in an approved multidisciplinary Huntington disease testing protocol. Please contact the laboratory at 503-494-5400 prior to drawing samples.
