APA Dictionary of Psychology

an autosomal recessive disorder characterized by scaly skin, spasticity, and intellectual developmental disorder, caused by several different genetic factors. Sweat glands are sparse or deficient. The scaliness varies in specific cases among populations from different regions of the world. [reported in 1957 by Torsten Sjögren (1896–1974), Swedish physician, and Tage Konrad Leopold Larsson (1905–1998), Swedish scientist]