1. A. H. M. Burghes is in the Department of Molecular and Cellular Biochemistry, Department of Neurology, and Department of Molecular Genetics, Ohio State University, Columbus, OH 43210, USA.
2. H. E. F. Vaessin is at the Neurobiotech Center and Department of Molecular Genetics, Ohio State University, Columbus, OH 43210, USA.
3. A. de la Chapelle is at the Human Cancer Genetics Program, Comprehensive Cancer Center, Ohio State University, Columbus, OH 43210, USA.