Delineation of 2q32q35 deletion phenotypes: two apparent "proximal" and "distal" syndromes

Abstract

We report on three patients with interstitial deletions of the long arm of chromosome 2 involving bands 2q32.1-q35. They presented with wide-ranging phenotypic variation including facial dysmorphisms, cleft palate, learning difficulties, behavioural issues and severe heart defects. Microarray analysis confirmed an 8.6 Mb deletion in patients 1 and 2 and a 24.7 Mb deletion in patient 3. We discuss the genes involved in the deleted regions including MYO1B, GLS, FRZB, SATB2, and CPS1 and compare the phenotype with those reported in the literature. Taken together, these data suggest that there is a spectrum of disease severity such that patients with deletions encompassing the region of 2q32.1q32.2, which includes the FRZB gene, show an apparently milder phenotype compared to those that lie further distal in 2q32.3q35 that encompasses the SATB2 gene.

Figure 1

G-banded karyotype and corresponding ideogram of chromosomes 2. Panels (a) and (b) show the deleted chromosomes 2 for patients 1 and 3, respectively. The left hand of each panel shows the G-banded chromosomes, and the right side shows the corresponding ideograms. The horizontal black arrows show the location of the deletion breakpoints.

Figure 2

Schematic of the chromosome 2 region encompassing the deletions detected in the patients reported here. Panel (a) shows an ideogram of chromosome 2. Panel (b) shows the OMIM genes and RefSeq genes that lie in the region of the deletions reported here. Panel (c) shows the location and extent of the deletions for patients 1, 2, and 3. The images in panels (a) and (b) are taken from the UCSC genome browser (http://genome.ucsc.edu/).