Chromosome 1q21.1 deletion syndrome

Chromosome 1q21.1 deletion syndrome is a condition caused by the deletion of a short portion of the long arm (q) of chromosome 1 at a locus called q21.1. The disorder demonstrates a heterogenous spectrum of manifestations including delayed milestones, learning difficulties, physical anomalies, congenital heart disease and both neurological and psychiatric dysfunction; although occasionally the disorder seems to be completely asymptomatic.