Interstitial deletions of the short arm of chromosome 4 in a patient with mental retardation and focal seizure.

Interstitial deletion of the proximal short arm of chromosome 4 has rarely been described. This defect is associated with variable clinical manifestations, including mental retardation, unusual facial appearance, and minor limb abnormalities. We describe a girl diagnosed with moderate mental retardation and seizures with an interstitial deletion of the short arm of chromosome 4 [46, XX, del(4)(p12p15.2)].