Muscle fiber involvement in Lowe syndrome

: Although it is well known fact that patients with Lowe syndrome have a delay in developmental milestones, muscle hypotonia and weakness, no detailed pathologic study to explain the muscle symptoms is available. In two patients with Lowe syndrome aged 22 years and 14 years, respectively, the biopsied biceps brachii muscles showed no significant morphologic changes except for small caliber fibers measuring almost 1/3 of the normal size. Although the muscle fiber type distribution is normal with no increase in undifferentiated type 2 C fibers, there remains a possibility of a certain defective neural influence on developing muscle fibers or metabolic defect. The muscle fiber immaturity is probably responsible for muscle weakness and hypotonia in this syndrome.