Huntington’s disease (HD) is a fatal genetic disorder that causes the progressive breakdown of nerve cells in the brain. It deteriorates a person’s physical and mental abilities during their prime working years and has no cure.
HD is a neurodegenerative disorder that is inherited in an autosomal dominant fashion.manifestations are associated with expansions of a Polymorphic CAG repeat in exon 1 of the HD gene located on chromosome 4p16.3. The presence Of an expanded CAG accounts for 99 percent of HD cases.
The CAG repeat of the HD gene is amplified by the polymerase chain reaction (pcr) using two sets of fluorescently labeled primers. The size of the repeat is determined by electrophoresis on an automated capillary DNA sequencer.