Juvenile Huntington’s disease in Malta

Abstract

Huntington’s disease is an autosomal dominant progressive neurological condition characterized by involuntary movements and dementia. The age of onset is related to the number of (CAG)n trinucleotide repeats in the Huntington gene. Rarely, the disease manifests itself first during childhood or adolescence as juvenile Huntington’s disease, and occurs when gene amplification occurs increasing greatly the number of repeats. Over the 11 year period from 1994 to 2006, three cases of Juvenile Huntington’s disease were recorded from among the families with Huntington’s disease referred to the genetic clinic for genetic counselling, pre-symptomatic DNA testing or diagnostic DNA testing. The affected individuals were three boys of ages 10, 14 and 21 years at the time of confirmation of the diagnosis by DNA tests. They were from three different families with strong family histories of Huntington’s disease. The presenting features of the juvenile cases were distinct from those of adult-onset Huntington’s disease. The most characteristic initial manifestations were behavior disorders and a characteristic speech in which words were uttered very rapidly in short phrases separated by short pauses. The speech disorder may be one of the earliest manifestations of motor dysfunction. The other motor manifestations were rigidity and myotonia. Choreiform movements developed later in the course of the disease in one of the youngest of the affected young individuals. All three individuals were males, had over 60 (CAG)n repeats and had inherited the gene from their fathers, with amplification of the trinucleotide repeats occurring in the process. Diagnosis of juvenile Huntington’s disease presents the ethical problems of informed consent and genetic testing in minors, and the delicate procedure of post-test counseling.