Simpson-Golabi-Behmel syndrome type 1
Simpson-Golabi-Behmel syndrome type 1A rare (130 patients in the world literature) X-linked condition (OMIM:312870) characterised by pre- and postnatal overgrowth (gigantism) and visceral and skeletal anomalies, including diastasis recti (an opening of muscles of the anterior abdominal wall) and umbilical and diaphragmatic hernias. The facial dysmorphia of these patients is highly characteristic with ocular hypertelorism, macrostomia, macroglossia with a deep central groove, a broad nose with an upturned tip, and palatal defects, resulting in an appearance likened to that of a bulldog (SGBS1 is also known as bulldog syndrome). About 10% of patients develop renal tumours in early childhood, including Wilms tumour and neuroblastoma.
Defects in GPC3, which encodes glypican 3, a cell surface proteoglycan thought to play a role in modulating growth of mesodermal tissues, cause Simpson-Golabi-Behmel syndrome.