Severe infantile dentatorubral pallidoluysian atrophy with extreme expansion of CAG repeats

Dentatorubral pallidoluysian atrophy (DRPLA) is an autosomal dominant disease that has a wide variety of clinical symptoms.1 There is a correlation between age at onset and clinical symptoms. Progressive myoclonus epilepsy (PME) is a usual feature of juvenile DRPLA; but late adult DRPLA patients usually experience cerebellar ataxia and hyperkinetic involuntary movements such as choreoathetosis, often without myoclonus or epilepsy.2 We report two unrelated patients with infantile DRPLA. ### Patient 1. The patient is a 4-year-old boy and the second child of healthy, nonconsanguineous Japanese parents without a family history of neurologic diseases. His father is 39 years old and his mother is 35 years old. He has a healthy 8-year-old brother. There were no major problems in the neonatal periods. He developed normally until age 6 months when his mother noticed decreased activity. At age 1 year, he could stand with support; but he began to regress slowly and became irritable. At age 2 years, he had difficulty controlling his head and swallowing, sometimes showing dystonic posture. …