Phenotypic features in a boy with monosomy 18 mosaicism

We report on a patient with mosaicism for monosomy 18, a chromosomal abnorm ality that has been reported only once previously. The patient had cleft li p and palate and mild behavioral and academic problems. His phenotype was m ilder in comparison with the previously reported patient by Khalifa et al. [1996: Clin Genet 49:318-320]. Further case reports of this chromosomal ano maly will be needed to determine a consistent phenotypic pattern to assist in management and genetic counseling. Am. J. Med. Genet. 95:229-232, 2000. (C) 2000 Wiley-Liss, Inc.