Self-mutilation in a patient with mucolipidosis III.

An 8-year-old girl with mucolipidosis III had self-mutilation of the distal phalanges of the second and third digits of her hands. She had neurophysiologic evidence of carpal tunnel syndrome, and consequent insensitivity to pain, which could explain the self-mutilation. Self-mutilation has not been previously described in lysosomal diseases in which carpal tunnel syndrome is frequently observed.