Does homozygosity advance the onset of dentatorubral-pallidoluysian atrophy?

We confirmed a homozygous type of relatively small expansion of CAG triplet repeats (57 repeats) in the short arm of chromosome 12 in a male patient with dentatorubral-pallidoluysian atrophy (DRPLA) by polymerase chain reaction. He showed early onset (age, 17 years) of DRPLA. There was good correlation of the age of onset with the number of triplet repeats. The homozygous state of the expansion of the triplet repeats was responsible for the early onset and severity of his DRPLA. NEUROLOGY 1995;45: 1934-1936