I am chairman of the Department of Human Genetics, Leiden University Medical Center, The Netherlands. My major research areas are neuromuscular and neurodegenerative diseases (with focus on Duchenne muscular dystrophy and Huntington's Disease); development and application of fluorescent in situ hybridization (FISH) for disease study; genome research and diagnostic technology. Researchers of my department have contributed to the finding of the genes defective in Duchenne muscular dystrophy, Polycystic Kidney Disease, Rubinstein-Taybi syndrome, Familial Hemiplegic migraine and Episodic Ataxia; to the mapping and identification of the repeat-deletion mutations in Facioscapulohumeral muscular dystrophy, and to the development of several mutation detection techniques, amongst others the Protein Truncation Test (PTT) which is now widely used in colon- and breast cancer diagnostics. I have strong interest in genome mapping, with a focus on the X-chromosome and chromosome 4. I am past president of the Dutch Society of Human Genetics (1993-2000), past president (1998-1999) and current senior vice-president of the international Human Genome Organisation (HUGO), editor-in-chief of the European Journal of Human Genetics, and board member of the European Society of Human Genetics.