Familial juvenile focal amyotrophy of the upper extremity (Hirayama disease). Superoxide dismutase 1 genotype and activity
W. Robberecht, T. Aguirre, L. Van den Bosch, P. Theys, H. Nees, J. J. Cassiman and G. Matthijs
Department of Neurology, University Hospital Gasthuisberg, Leuven, Belgium.
BACKGROUND: Juvenile focal amyotrophy of the arm is an unusual focal motor
neuron disease that is rarely familial. Its pathogenesis is unknown. We
recently described a family with amyotrophic lateral sclerosis associated
with a mutation in the superoxide dismutase 1 (SOD1) gene substituting an
aspartate for an alanine (D9OA). One of the carriers of this mutation had
focal and nonprogressive amyotrophy of the arm, suggesting that focal
amyotrophy might be associated with SOD1 mutations. OBJECTIVES: To describe
the phenotype of 2 brothers with juvenile focal amyotrophy of the upper
extremity and to characterize their SOD1 genotype and SOD activity.
METHODS: Polymerase chain reaction and sequencing of the SOD1 gene and
colorimetric measurement of the enzyme activity. RESULTS: We compared the
phenotype of our patients to that of 375 patients described in the Western
literature. The 5 exons of the SOD1 gene were normal, as was the SOD
activity in red blood cells.
