Richard Trembath is Professor of Medical Genetics at the University of Leicester. He is distinguished for his contributions to medical molecular genetic research, in a wide-ranging programme aimed at delineating the molecular genetic basis of single gene and common complex disorders. With Anita Harding, he was the first to show that mutations in mitochondrial DNA can predispose to diabetes mellitus. Recent major contributions include the positional cloning of genes involved in the most common syndromic form of hearing loss, Pendred syndrome; the identification of the gene mutated in partial lipodystophy, an adipocyte disorder; and most recently the characterisation of the molecular genetic basis of the vascular disorder, primary pulmonary hypertension.