Keratosis pilaris and ulerythema ophryogenes associated with an 18p deletion caused by a Y/18 translocation

We present a patient with partial monosomy of the short arm of chromosome 1 8 caused by de novo translocation t(Y;18) and a generalized form of keratos is pilaris (keratosis pilaris affecting the skin follicles of the trunk, li mbs and face-ulerythema ophryogenes). Two-color FISH with centromere-specif ic Y and 18 DNA probes identified the derivative chromosome 18 as a dicentr ic with breakpoints in p11.2 on both involved chromosomes. The patient had another normal Y chromosome. This is a third report the presence of a chrom osome 18p deletion (and first case of a translocation involving 18p and a s ex chromosome) with this genodermatosis. Our data suggest that the short ar m of chromosome 18 is a candidate region for a gene causing keratosis pilar is. Unmasking of a recessive mutation at the disease locus by deletion of t he wild type allele could be the cause of the recessive genodermatosis. Am. J. Med, Genet. 85:179-182, 1999. (C) 1999 Wiley-Liss, Inc.