© Martinez-Agosto Laboratory, Department of Human Genetics, University of California, Los Angeles, 2008-2015.

 

Simpson-Golabi-Behmel

Description:
Simpson-Golabi-Behmel syndrome (SGBS) is characterized by pre- and postnatal macrosomia, distinctive craniofacies (macrocephaly, ocular hypertelorism, macrostomia, macroglossia, palatal abnormalities), and commonly, mild to severe mental retardation with or without structural brain anomalies. Other, variable findings include supernumerary nipples, diastasis recti/umbilical hernia, congenital heart defects, renal defects (nephromegaly, multicystic kidneys, hydronephrosis, hydroureter, duplicated ureters), and GI anomalies (pyloric ring, Meckel's diverticulum, intestinal malrotation, hepatosplenomegaly, hyperplasia of islets of Langerhans, choledochal cysts, polysplenia). Skeletal anomalies can include vertebral fusion, scoliosis, pectus excavatum, rib anomalies, winged scapula, and congenital hip dislocation. Hand anomalies can include large hands, broad thumbs, brachydactyly, syndactyly, clinodactyly, and postaxial polydactyly. Tumor frequency is about 10%; reported tumors include Wilms tumor, hepatoblastoma, adrenal neuroblastoma, gonadoblastoma, and hepatocellular carcinoma.

Testing:
The diagnosis of SGBS is based on clinical findings, family history consistent with X-linked inheritance, and molecular genetic testing of GPC3, the only gene currently known to be associated with SGBS. Mutation detection rate using sequence analysis and deletion analysis is 37%-70%. Testing is clinically available.

More information:
Simpson-Golabi-Behmel