Genetics
The human genome contains two atrophin genes; DRPLA has been correlated to the expansion of the polyglutamine region of the atrophin-1 gene on chromosome 12p13.3. A normal number of CAG repeats in the atrophin-1 gene is 7-34, affected individuals display 49-93 repeats. DRPLA displays anticipation, an inverse correlation between the size of the expanded CAG repeat and the age of symptom onset. Paternal transmission results in more prominent anticipation (26–29 years) than maternal transmission (14 to 15 years).
Read more about this topic: Dentatorubral-pallidoluysian Atrophy