INTERSTITIAL DELETION OF THE LONG ARM OF CHROMOSOME-18, DEL(18)(Q12.2Q21.1) - A REPORT OF 3 CASES OF AN AUTOSOMAL DELETION WITH A MILD PHENOTYPE

We describe three unrelated patients with apparently identical interstitial deletions of the segment (18) (q12.2q21.1). They were a short and markedly mentally retarded 5 year old girl, a macrocephalic and obese 2 1/2 year old boy with moderate mental retardation, and a macrocephalic, severely mentally retarded 5 year old boy. Findings common to all five liveborn patients so far identified as carrying this deletion include a pattern of minor dysmorphic features (prominent forehead, ptosis of the upper eyelids, full periorbital tissue, epicanthic folds, strabismus), muscular hypotonia, seizures, behavioural disorders, and lack of major malformations.