Familial simple hypohidrosis with abnormal palmar dermal ridges.

A brother and sister born to nonconsanguineous, Iranian Jewish parents were found to have simple hypohidrosis. Pilocarpine produced only little sweating, and external heat and physical effort were associated with elevation of body temperature. Abnormal palmar dermal ridges were considered to be associated with paucity of sweat pores and glands. Biopsy supported this view since only one normal sweat gland and duct was found in a 5 mm punch.