is a rare condition characterized by progressive, painful, intermittent muscle spasms, diarrhea or unusual malabsorption, amenorrhea, alopecia universalis, short stature, and skeletal abnormalities. Progressive painful intermittent muscle spasms usually start between 6 to 15 years of age. Alopecia universalis also appears around age 10. About half of affected individuals experience malabsorption, specifically of carbohydrates. The skeletal abnormalities may be secondary to muscle spasms. The main endocrine disorder is primary amenorrhea. All cases have apparently been sporadic, even when occurring in large families. The exact cause is unknown; but some researchers have speculated that Satoyoshi syndrome is an autoimmune disorder. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.