Typical Clinical Findings Should Prompt Investigation for Juvenile Huntington Disease

Abstract

An 11-year-old boy presented for neurological evaluation with a 5-year history of global developmental regression, abnormal involuntary movements, and worsening behavioral problems. He was adopted at 14 months of age and there was limited prenatal or family history. In early childhood, he had appropriate gross motor, fine motor, and language development, but “shakiness” was noted by his adoptive parents. In first grade, he was able to ride a bicycle, participate in gym class, dress himself, use utensils, write in cursive, and read at grade level. Since that time, a slow regression of fine motor, gross motor, and language skills was noted. His handwriting became illegible and he was having difficulty dressing himself. He walked on the edges of his feet and was no longer able to ride a bicycle or run without difficulty. His speech became unintelligible to strangers at the age of 9 years and he had significant difficulty with impulse control and memory. There was no known history of seizures. He had multiple involuntary movements of his arms and hands, such as hand-curling or arm-swinging, and had received the diagnosis of Tourette syndrome. He was under treatment with risperidone, citalopram, and clonidine for his involuntary movements without significant benefit. His physical examination revealed mild generalized hypertonia and difficulty with tandem gait. Choreiform movements of the extremities were noted. No myoclonus was seen. His speech was dysarthric with poor intelligibility and he spoke in oneto two-word phrases. He tended to walk on the outside of the feet with the toes turned inward. There was mild difficulty with tandem gait but he was able to walk on his toes and heels without difficulty. Neuropsychological testing revealed a full-scale IQ (FIQ) in the low-average range (FIQ 1⁄4 80), where it had been normal (FIQ 1⁄4 97) 5 years prior. Regression was noted on testing in verbal skills, speed of information processing, and math skills. EEG demonstrated diffuse slowing of the background