Abstract

An extra G band was found inserted into chromosome 11q23.2 in a boy who had severe developmental delay and anal stenosis. Cytogenetic characterisation of this extra band showed that it was composed of Q band brilliant, C band heterochromatin. It was also present in clinically normal subjects in two other generations and was therefore presumed to be unrelated to the clinical abnormalities in the proband. Although rare, this cytogenetic anomaly may be useful as a genetic marker for 11q23.2.