Unbalanced three-way chromosomal translocation leading to deletion 18q and duplication 20p

Abstract In 1980, a case report on a boy with cleft palate, club feet, dysmorphic features, and developmental delay was published by Bijlsma as a possible distinct syndrome. This case is listed in the London Medical Databases version 1.0. We have reevaluated this patient at adult age. Using high resolution karyotyping and Affymetrix 250k SNP array analysis we identified an unbalanced three-way translocation with breakpoints at 17q22, 18q22.1, and 20p12.2 leading to deletion 18q and duplication 20p. Also, a 715 kb duplication in 1p34.2 and a 245 kb deletion at 1p21.1 were found. Mental retardation, cleft palate, and club feet have repeatedly been reported in deletion 18q patients and therefore we conclude that most of the patient’s features can be explained by an 18q deletion.