What is Huntington's disease?

A late but variable age onset lethal human disease of nerve degeneration. Inherited as an autosomal dominant phenotype. Shows imprinting individuals inheriting HD from their father show significantly earlier onset than those inheriting a maternal allele. Shows genetic anticipation, in that the severity increase and age of onset decreases in affected individuals of later generations in a pedigree. The HD gene, encoding a protein called huntingtin, has been cloned.