Syndrome with characteristics of severe pre and post-natal growth retardation, microcephaly, intractable feeding difficulties, mild psychomotor retardation, hypotonia and facial dysmorphism. It has been reported in 2 unrelated patients. Facial dysmorphism includes high forehead, broad nasal bridge, thin upper lip, small chin and malformed ears. In addition, the patients presented with skin, iris and hair hypopigmentation and abnormal adipose tissue distribution. The syndrome is caused by an interstitial deletion of paternal origin at 20q13.2q13.3. In the 2 cases, the deletion was approximately 4.5Mb in size and encompassed the GNAS imprinted locus; the loss of the paternally expressed GNAS gene might account for the severe pre and post-natal retardation and intractable feeding difficulties observed in the patients. [from SNOMEDCT_US]