Molecular Characterization of a Patient With 3p Deletion Syndrome and a Review of the Literature
AMERICAN JOURNAL OF MEDICAL GENETICS PART A
Authors: Fernandez, Thomas V.; Garcia-Gonzalez, I. J.; Mason, Christopher E.; Hernandez-Zaragoza, G.; Ledezma-Rodriguez, V. C.; Anguiano-Alvarez, V. M.; E'Vega, R.; Gutierrez-Angulo, M.; Maya, M. L.; Garcia-Bejarano, H. E.; Gonzalez-Cruz, M.; Barrios, S.; Atorga, R.; Lopez-Cardona, M. G.; Armendariz-Borunda, J.; State, Matthew W.; Davalos, Nory O.
Abstract
3p deletion syndrome is a rare disorder involving developmental delay, dysmorphic physical features, and growth retardation. Molecular mapping of several cases in the literature have identified a critical region on chromosome 3p26. We present a child patient with characteristic features of 3p deletion syndrome and a de novo unbalanced translocation involving chromosomes 3 and 13. Fine mapping of this rearrangement using fluorescence in situ hybridization (FISH) and array-based comparative genomic hybridization (aCGH) revealed an unbalanced abnormality including a 4.5 Mb terminal deletion of chromosome 3p, telomeric to ITPR1 on 3p26.2, which was not previously identified with routine cytogenetic analysis. In addition, these investigations confirmed and refined the boundaries of a 26.5 Mb deletion of chromosome 13. This study confirms the minimal candidate region for 3p deletion syndrome, provides further evidence implicating haploinsufficiency of CNTN4 in the disorder, and demonstrates the utility of high-resolution investigations of rare chromosomal rearrangements. (c) 2008 Wiley-Liss, Inc.
FISH and array-CGH analysis of a complex chromosome 3 aberration suggests that loss of CNTN4 and CRBN contributes to mental retardation in 3pter deletions
AMERICAN JOURNAL OF MEDICAL GENETICS PART A
Authors: Dijkhuizen, Trijnie; van Essen, Ton; van der Vlies, Pieter; Verheij, Joke B. G. M.; Sikkema-Raddatz, Birgit; van der Veen, Anneke Y.; Gerssen-Schoorl, Klasien B. J.; Buys, Charles H. C. M.; Kok, Klaas
Abstract
Imbalances of 3p telomeric sequences cause 3p- and trisomy 3p syndrome, respectively, showing distinct, but also shared clinical features. No causative genes have been identified in trisomy 3p patients, but for the 3p- syndrome, there is growing evidence that monosomy for one or more of four genes at 3pter, CHL1, CNTN4, CRBN and MEGAP/srGAP3, may play a causative role. We describe here an analysis of a complex chromosome 3p aberration in a severely mentally retarded patient that revealed two adjacent segments with different copy number gains and a distal deletion. The deletion in this patient included the loci for CHL1, CNTN4, and CRBN, and narrowed the critical segment associated with the 3p- syndrome to 1.5 Mb, including the loci for CNTN4 and CRBN. We speculate that the deletion contributes more to this patient's phenotype than the gains that were observed. We suggest that 3p- syndrome associated features are primarily caused by loss of CNTN4 and CRBN, with loss of CHL1 probably having an additional detrimental effect on the cognitive functioning of the present patient. (c) 2006 Wiley-Liss, Inc.