Brief clinical report - Functional disomy for Xq26.3-qter in a boy with anunbalanced t(X;21)(q26.3;p11.2) translocation

A nine-month-old boy, with functional disomy for Xq26-qter and multiple con genital abnormalities, is reported. The boy had severe pre- and postnatal g rowth retardation, profound developmental delay, hypotonia, microcephaly, a genesis of the corpus callosum, dysmorphic facial features, cryptorchidism, and left multidysplastic kidney, He developed feeding difficulties and inf antile spasms. G-banding analysis of his chromosomes showed additional mate rial on the short arm of chromosome 21, His parents refused to submit to ch romosome analysis, Analysis with chromosome microdissection followed by rev erse and forward chromosome painting indicated his karyotype as 46,XY,der(2 1)t(X;21)(q26;p11.2). This is the first description of pure functional diso my for Xq26-qter due to an unbalanced X-autosome translocation, (C) 2001 Wi ley-Liss, Inc.