MUSCLE INVOLVEMENT IN CONGENITAL INSENSITIVITY TO PAIN WITH ANHIDROSIS

A patient with congenital insensitivity to pain with anhidrosis, who h ad characteristic clinical features and biopsied sural nerve, is prese nted, Nerve pathology findings indicated a loss of the small myelinate d and unmyelinated fibers, Biopsied muscle disclosed a marked variatio n in fiber size, some small fibers with central nuclei, and a small nu mber of small angulated fibers, consistent with neurogenic and myogeni c changes. Many patients with congenital insensitivity to pain with an hidrosis had muscle weakness and absent or decreased deep tendon refle xes with normal nerve conduction velocity, We confirmed that lack of s mall myelinated fibers in motor neurons resulted in a striking change of muscle in our patient.