An HDR (hypoparathyroidism, deafness, renal dysplasia) syndrome locus maps distal to the DiGeorge syndrome region on 10p13/14
- Peter Lichtnera,
- Rainer Königb,
- Tomonobu Hasegawac,
- Hilde Van Eschd,
- Thomas Meitingera,
- Simone Schuffenhauera
- aDepartment of Medical Genetics, Children's Hospital, Ludwig-Maximilians-University Munich, Goethestrasse 29, D-80336 Munich, Germany, bInstitute of Human Genetics Humangenetik, Johann Wolfgang Goethe University Frankfurt, Theodor-Stern-Kai 7, D-60590 Frankfurt, Germany, cDepartment of Paediatrics, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku Tokyo, Japan, dLaboratory for Molecular Oncology, Centre for Human Genetics, University of Leuven and Flanders, Interuniversity Institute for Biotechnology, B-3000 Leuven, Belgium
- Dr Schuffenhauer
- Revised 25 August 1999
- Accepted 10 September 1999
Abstract
Partial monosomy 10p is a rare chromosomal condition and a significant proportion of patients show features of DiGeorge syndrome (DGS) and velocardiofacial syndrome (VCFS). A critical haploinsufficiency region for DGS/VCFS was defined on 10p (DGCR2). We performed molecular deletion analysis of two further patients with partial monosomy 10p, who showed hypoparathyroidism, deafness, and renal dysplasia or renal insufficiency, but no cardiac defect, cleft palate, or reduced T cell levels. Previously, the combination of hypoparathyroidism, deafness, and renal dysplasia has been proposed to represent a specific syndrome (MIM 146255) under the acronym HDR. In addition to the two patients in this report, at least four published cases with partial monosomy 10p show the triad of HDR and 14 other patients present with at least two of the three features. We therefore conclude that HDR syndrome can be associated with partial monosomy 10p. Based on molecular deletion analysis and the clinical data, we suggest that the DGS/VCFS phenotype associated with 10p deletion can be considered as a contiguous gene syndrome owing to haploinsufficiency of two different regions. Hemizygosity of the proximal region, designatedDGCR2, can cause cardiac defect and T cell deficiency. Hemizygosity of the distal region, designatedHDR1, can cause hypoparathyroidism and in addition sensorineuronal deafness and renal dysplasia/insufficiency or a subset of this triad.
