1. Department of Pediatrics, National University of Singapore, Lower Kent Ridge Road, Singapore
2. Faculty of Health Science, Kobe University School of Medicine, Tomogaoka, Suma-ku, Kobe 654-01, Japan
3. Division of Genetics, International Center for Medical Research, Kobe University School of Medicine, Kusunoki-cho, Chuo-ku, Kobe 650, Japan
4. Department of Neonatology, National University Hospital, Lower Kent Ridge Road, Singapore