A boy with a submicroscopic 22qter deletion, general overgrowth and features suggestive of FG syndrome

Over recent years, submicroscopic subtelomeric rearrangements have been sho wn to be a significant cause of mental retardation and, therefore, such abn ormalities should be considered in every child with moderate to severe reta rdation with additional features suggestive of a chromosomal abnormality. T he FG syndrome is an X-linked recessive mental retardation syndrome with co ngenital hypotonia, relative macrocephaly, a characteristic facies and cons tipation. We describe a severely mentally retarded boy with a history of severe const ipation, truncal hypotonia, facial dysmorphism, fetal pads, and joint laxit y, leading to an initial diagnosis of FG syndrome at the age of 3 years. Cl inical re-evaluation at the age of 6 years; when he showed signs of general overgrowth, initiated a telomere screen, and a submicroscopic 22q13.3 telo mere deletion was detected. The features suggestive of FG syndrome in this boy with a 22q13.3 --> qter deletion may indicate testing for submicroscopic 22qter deletions in patien ts with atypical features of FG syndrome without a definite X-linked family history.