HUNTINGTON DISEASE
DIAGNOSIS |
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Diagnosis of Huntington's disease begins with a detailed
medical history, and a thorough physical and neurological exam.
Family medical history is very important, since Huntington's disease is an inherited
disease. Magnetic resonance imaging (MRI) or
A genetic test is available for confirmation of the clinical
diagnosis. In this test, a small blood sample is taken, and DNA from
it is analyzed to determine the CAG repeat number. A person with a
repeat number of 30 or below will not develop Huntington's disease. A person with a
repeat number between 35 and 40 may not develop the disease within
their normal lifespan. A person with a very high number of repeats
(70 or above) is likely to develop the juvenile-onset form.
Prenatal testing is available. A person at risk for Huntington's disease (a child of
an affected person) may obtain fetal testing without determining
whether she herself carries the gene. This "nondisclosing" test,
also called a linkage test, examines the pattern of DNA near the
gene in both parent and fetus, but does not analyze for the triple
repeat itself. If the DNA patterns do not match, the fetus can be
assumed not to have inherited the Huntington's disease gene, even if present in the
parent. A pattern match indicates the fetus probably has the same
genetic makeup of the at-risk parent. It does not indicate whether
the parent (or fetus) actually has the defective gene. |
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| HUNTINGTON DISEASE RELATED ITEMS |
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