Infantile Huntington's disease in Mexico's National Institute of Neurology and Neurosurgery

Abstract

Objective: Analysis of the clinical expression and molecular behavior of the CAG repeat expansion responsible for Huntington's disease (HD) in children attending a tertiary care center in Mexico.

Background: Clinical manifestations of Huntington's disease usually appear between the ages of 35 and 45, but there is a number of patients with an early onset of disease: Juvenile HD is defined by an onset before 20 years of age, while Infantile HD is characterized by appearance of the first symptoms prior to the patient's 10th. birthday. This last group constitutes less than 1% of all HD patients, and shows a distinct clinical behavior with large CAG repeat expansions in the IT 15 gene.

Methods: Clinical files from 145 families with HD who attend the National Institute of Neurology and Neurosurgery were reviewed in order to identify individuals with an age of onset before 10 years of age. Molecular detection of the CAG repeat expansion was carried out in 4 out of 5 patients identified, and clinical and molecular behavior were analyzed.

Results: The PCR assay demonstrated the CAG repeat expansion in the children tested, with number of copies ranging from 54 to more than 120. All patients had paternal inheritance, and had a clinically aggressive illness, with prominent rigidity, dystonia, seizures, and behavioral disorders. Two of these children have already died.

Conclusions: Huntington's disease should be considered as a differential diagnosis of a variety of progressive motor, cognitive and/or affective disorders even in the absence of a clearly affected parent.