¹Section on Molecular Dysmorphology, Program on Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, DHHS, Bethesda, MD, USA

Correspondence: Dr FD Porter, Program on Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, DHHS, Bld. 10, Rm. 9D42, 10 Center Dr, Bethesda, MD 20892 USA. Tel: +1 301 435 4432; Fax: +1 301 480 5791. E-mail: fdporter@mail.nih.gov

Received 1 October 2007; Revised 18 December 2007; Accepted 6 January 2008; Published online 20 February 2008.

Abstract

Smith–Lemli–Opitz syndrome (SLOS) is a malformation syndrome due to a deficiency of 7-dehydrocholesterol reductase (DHCR7). DHCR7 primarily catalyzes the reduction of 7-dehydrocholesterol (7DHC) to cholesterol. In SLOS, this results in decreased cholesterol and increased 7DHC levels, both during embryonic development and after birth. The malformations found in SLOS may result from decreased cholesterol, increased 7DHC or a combination of these two factors. This review discusses the clinical aspects and diagnosis of SLOS, therapeutic interventions and the current understanding of pathophysiological processes involved in SLOS.