- Ataxia, chorea, seizures, and dementia
- Dentatorubropallidoluysian atrophy
- Haw River syndrome
- Myoclonic epilepsy with choreoathetosis
DRPLA is caused by a mutation in the ATN1 gene. This gene provides instructions for making a protein called atrophin 1. Although the function of atrophin 1 is unclear, it likely plays an important role in nerve cells (neurons) in many areas of the brain.
The ATN1 mutation that causes DRPLA involves a DNA segment known as a CAG trinucleotide repeat. This segment is made up of a series of three DNA building blocks (cytosine, adenine, and guanine) that appear multiple times in a row on the gene. Normally, this CAG segment is repeated 6 to 35 times within the ATN1 gene. In people with DRPLA, the CAG segment is repeated at least 48 times (and sometimes much more). The abnormally long CAG trinucleotide repeat changes the structure of the atrophin 1 protein, which then accumulates in neurons and interferes with normal cell functions. The dysfunction and eventual death of these neurons lead to the signs and symptoms associated with DRPLA.
- Dentatorubral-pallidoluysian atrophy. Genetics Home Reference (GHR). 2008; http://ghr.nlm.nih.gov/condition=dentatorubralpallidoluysianatrophy. Accessed 5/10/2010.