Spontaneous hypothermia in a young boy.

A 13-year-old boy who maintains his body temperature between 33 and 35 degrees C was investigated. Tests of peripheral and central thermoregulatory function did not show a specific abnormality, except for some generalised hypothalamic dysfunction of unknown aetiology. He responded appropriated when his temperature was altered from its usual low level. His temperature regulatory mechanisms appeared to be set at a temperature lower than is normal.