Simpson-Golabi-Behmel syndrome in a female: A case report and an unsolved issue.

Simpson-Golabi-Behmel syndrome is an X-linked recessive overgrowth condition caused by alterations in GPC3 gene, encoding for the cell surface receptor glypican 3, whose clinical manifestations in affected males are well known. Conversely, there is little information regarding affected females, with very few reported cases, and a clinical definition of this phenotype is still lacking. In the present report we describe an additional case, the first to receive a primary molecular diagnosis based on strong clinical suspicion. Possible explanations for full clinical expression of X-linked recessive conditions in females include several mechanisms, such as skewed X inactivation or homozygosity/compound heterozygosity of the causal mutation. Both of these were excluded in our case. Given that the possibility of full expression of SGBS in females is now firmly established, we recommend that GPC3 analysis be performed in all suggestive female cases.