[A case of juvenile type dentatorubral-pallidoluysian atrophy (DRPLA) with psychomotor retardation since infancy].

We report here a case of an 11-year-old boy with juvenile type of dentatorubral-pallidoluysian atrophy (DRPLA). His psychomotor development has been delayed since infancy and cerebellar ataxia was noted at the age of 2 years, indicating an early onset. At the age of 6 years, he had progressive myoclonus epilepsy (PME) and underwent a series of neuroradiological, electrophysiological and pathological examinations, which failed to reveal the etiology. Gene analysis performed at the age of 11 years revealed an expanded CAG repeat at the DRPLA locus in both the patient and his asymptomatic father. In the absence of a positive family history, a diagnosis of DRPLA may be difficult due to its clinical variability. We conclude that DRPLA should be taken into account in the differential diagnosis of childhood PME and that gene analysis should be performed to confirm a diagnosis of DRPLA.