X linked severe mental retardation, craniofacial dysmorphology, epilepsy, ophthalmoplegia, and cerebellar atrophy in a large South African kindred is localised to Xq24-q27
- Arnold L Christiansona,
- Roger E Stevensonb,
- C H van der Meydenc,
- Julie Pelsera,
- Francois W Therond,
- Petro L van Rensburge,
- Michael Chandlerb,
- Charles E Schwartzb
- aDepartment of Human Genetics and Developmental Biology, Faculty of Medicine, University of Pretoria, PO Box 2034, Pretoria 0001, South Africa, bJ C Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, South Carolina, USA, cDepartment of Neurology, Faculty of Medicine, University of Pretoria, Pretoria, South Africa, dDepartment of Anatomical Pathology, Faculty of Medicine, University of Pretoria, Pretoria, South Africa, eGenetic Services Division, Gauteng Department of Health, Gauteng Provincial Government, Pretoria, South Africa
- Professor Christianson.
- Revised 15 June 1999
- Accepted 5 July 1999
Abstract
To date over 150 X linked mental retardation (XLMR) conditions have been documented. We describe a five generation South African family with XLMR, comprising 16 affected males and 10 carrier females. The clinical features common to the 16 males included profound mental retardation (100%), mutism despite apparently normal hearing (100%), grand mal epilepsy (87.5%), and limited life expectancy (68.8%). Of the four affected males examined, all had mild craniofacial dysmorphology and three were noted to have bilateral ophthalmoplegia and truncal ataxia. Three of 10 obligate female carriers had mild mental retardation. Cerebellar and brain stem atrophy was shown by cranial imaging and postmortem examination. Linkage analysis shows the gene to be located between markers DXS424 (Xq24) and DXS548 (Xq27.3), with a maximum two point lod score of 3.10.
