J Clin Endocrinol Metab 2006 Jun 28;91(6):2380-8. Epub 2006 Mar 28.
Section on Endocrinology and Genetics, and Pediatric Endocrinology Training Program, Developmental Endocrinology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.