#ExistRefRange>Negative: This individual has two normal alleles; and therefore, is neither a carrier nor will be affected with Huntington disease.
#ExistInterpData>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.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.
See Compliance Statement C: www.aruplab.com/CS
||Number of CAG Repeats
|Mutable normal allele
|HD allele with reduced penetrance
||If an expanded allele is detected by PCR and capillary electrophoresis, but cannot be sized (typically due to large expansions greater than 80 repeats), Southern blot will be added to determine the size of the expanded CAG repeat. Additional charges apply.
If reflexed, add 81479