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Huntington Disease Mutation W Rfx
Test CodeHDMUT
Alias/See Also
Huntington Disease (HD) Mutation by PCR
CPT Codes
81401 if refexed add 81479
Physician Attestation of Informed Consent
Requires informed consent. Please contact 381-2385 or follow this link: http://ltd.aruplab.com/Tests/Pdf/23
Preferred Specimen
5.0 mL of whole blood
Minimum Volume
3.0 mL of whole blood
Instructions
A completed HD specific consent form, signed by the patient (or legal guardian) and physician, is required for all specimens. Testing for patients under the age of 18 years or fetal specimens is not offered.
Transport Container
EDTA (lavendar top), K2EDTA (pink top), or ACD Solution A or B (yellow top)
Transport Temperature
Refrigerated
Specimen Stability
Ambient: 72 hours
Refrigerated: 1 week
Frozen: 1 month
Refrigerated: 1 week
Frozen: 1 month
Methodology
Polymerase Chain Reaction/Fragment Analysis
Setup Schedule
Varies
Report Available
7-10 days after receipt of fully completed HD consent form
Reference Range
Negative: This individual has two normal alleles; and therefore, is neither a carrier nor will be affected with Huntington disease
Clinical Significance
Huntington Disease Background Info:
Characteristics: Neurodegenerative disorder causing progressive cognitive, motor, and psychiatric disturbances typically beginning at 35-44 years of age
(Although, 5 percent are affected as juveniles and 25 percent affected after age 50).
Incidence: 1 in 15,000.
Inheritance: Autosomal dominant.
Cause: Expanded number of CAG repeats in the HD gene (27-35 repeats-unaffected, intermediate; 36-39 repeats-reduced penetrance; 40+ repeats-affected, full penetrance).
Clinical Sensitivity and Specificity: 99 percent.
Methodology: Chimeric PCR followed by size analysis using capillary electrophoresis; alleles with greater than 80 CAG repeats may require Southern blot analysis to help estimate repeat size.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Other neurodegenerative disorders will not be detected. Sizing by Southern blot is not precise, varying up to +/-15 repeats. Rare, previously unreported variants may interfere with PCR amplification
Characteristics: Neurodegenerative disorder causing progressive cognitive, motor, and psychiatric disturbances typically beginning at 35-44 years of age
(Although, 5 percent are affected as juveniles and 25 percent affected after age 50).
Incidence: 1 in 15,000.
Inheritance: Autosomal dominant.
Cause: Expanded number of CAG repeats in the HD gene (27-35 repeats-unaffected, intermediate; 36-39 repeats-reduced penetrance; 40+ repeats-affected, full penetrance).
Clinical Sensitivity and Specificity: 99 percent.
Methodology: Chimeric PCR followed by size analysis using capillary electrophoresis; alleles with greater than 80 CAG repeats may require Southern blot analysis to help estimate repeat size.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Other neurodegenerative disorders will not be detected. Sizing by Southern blot is not precise, varying up to +/-15 repeats. Rare, previously unreported variants may interfere with PCR amplification
Performing Laboratory
ARUP Laboratories
