(SGBS) is a condition that affects many parts of the body and occurs primarily in males. It is an overgrowth syndrome, which means that affected individuals have macrosomia and continue to grow and gain weight at an unusual rate. The severity varies from very mild forms in carrier females to infantile lethal forms in affected males. Individuals typically have distinctive facial features including hypertelorism, macrostomia, macroglossia, a broad nose with an upturned tip, and palatal abnormalities. Other, variable findings include extra nipples, diastasis recti, umbilical hernia, congenital heart defects, renal defects, gastrointestinal anomalies, skeletal anomalies, hand anomalies, genitourinary abnormalities, and hepatosplenomegaly. Some people with the condition have mild to severe intellectual disability. About 10 percent of people with SGBS develop tumors in early childhood, including Wilms tumor and neuroblastoma. Some cases of SGBS are caused by mutations in the GPC3 gene and in other cases, the cause is unknown. It is inherited in an X-linked recessive manner. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.