Phenotypic variability of del(2) (q22-q23): report of a case with a review of the literature.

An interstitial deletion of 2q22-q23 was found in a 2.5 year old boy with multiple congenital abnormalities (including Hirschsprung's disease) and severe mental retardation. Comparison with seven additional cases of 2q deletions from the literature does not allow the delineation of a clinically recognizable syndrome. Some of the previously reported patients had features rarely observed in chromosomal syndromes (i.e., occipital encephalocele and tracheo-esophageal fistula). Possible reasons for such phenotypic variability are briefly discussed.