Expansion of the deletion 13q syndrome phenotype: a case report.

The phenotypic description of deletion 13q syndrome is dependent on the location and size of the deleted segment. At present, the syndrome is divided into 3 groups based on the deletion's location relative to chromosomal band 13q32. Groups 1 (proximal to q32) and 2 (including q32) have shown distinctive phenotypes including mental retardation and growth deficiency, whereas group 3 (q33-34 deletion) is defined by the presence of mental retardation but usually the absence of major malformations. The authors report an 8-year-old Hispanic female with dysmorphic facial features, microcephaly, moderate to severe mental retardation, and uncontrolled epilepsy associated with a terminal 13q33.3 deletion. These features expand the characterization of the phenotype associated with group 3 of the 13q deletion syndrome to include major clinical manifestations. This case report will contribute to more accurate genetic counseling as well as may help identify more individuals with this syndrome.