Interstitial deletion of the long arm of chromosome 6 associated with unusual limb anomalies: report of two new patients and review of the literature.

We report on unusual manifestations in 2 unrelated children with interstitial deletion of 6q, with nearly identical breakpoints of 6q16.2q23.1 and 6q16.3q22.3. Major findings include growth retardation, profound developmental delay, microcephaly, facial anomalies, sparse hair, congenital heart defects, and striking hand malformations. Discordant anomalies were duodenal atresia and hypoplastic genitalia in 1 child. Split-hand defect, polydactyly, gastrointestinal anomalies, and ectodermal dysplasia have not been described previously in children with 6q deletion. The presence of hand malformations in 2 children with similar deletion breakpoints strongly suggests that this is a candidate region for one or more genes involved in limb development. Comparison of the clinical findings of other patients with 6q2 deletion suggests a recognizable phenotype.