FaCD Online Syndrome Fact Sheet

Last updated: 26 May 2009

Name: Smith-Lemli-Opitz syndrome

Synonym: SLOS type I & II

Mode of Inheritance: AR

OMIM number: 270400  


DHCR7, mapped to 11q12-q13

Tumor features (possible)

brain tumor
germ cell tumor, extra-gonadal
ovarian germ cell tumor
pituitary gland tumor

Non-tumor features

abnormal lung lobulation
anteverted nares
cleft palate
developmental delay/mental deficiency/mental retardation
epicanthal folds
forehead, broad
growth deficieny
heart, congenital defect
male (46,XY) pseudohermaphroditism
nose, short
polydactyly, postaxial
renal cysts


This disorder is characterized by typical craniofacial dysmorphisms, neurological abnormalities, congenital anomalies of extremities and genitourinary system[1]. There is a wide phenotypic variation between and within affected families. The severe cases are referred to as type II. The disorder is caused by deficiency of 7-dehydrocholesterol reductase (DHCR7). Gonads may be testes, ovotestes, normal ovaria or absent.

Patsner et al.[3] reported a 19-year-old woman with a malignant mixed germ cell tumor of the ovary. A lipoma of the pituitary gland in an SLO patient was reported by Herman et al[4]. Oslejskova et al[5] reported a cerebral dysgerminoma in a 16-year-old boy.


[1] Kelley RI, Hennekam RCM. The Smith-Lemli-Opitz syndrome. J Med Genet 2000; 37:321-335.
[2] Porter FD. Smith-Lemli-Opitz syndrome: pathogenesis, diagnosis and management. European journal of human genetics : EJHG 2008; .
[3] Patsner B, Mann WJ, Chumas J. Malignant mixed germ cell tumor of the ovary in a young woman with Smith-Lemli-Opitz syndrome. Gynecol Oncol 1989; 33(3):386-388.
[4] Herman TE, Siegel MJ, Lee BC, Dowton SB. Smith-Lemli-Opitz syndrome type II: report of a case with additional radiographic findings. Pediatric radiology 1993; 23(1):37-40.
[5] Oslejskova H, Horinova V, Sterba J, Pavelka Z, Babovic-Vuksanovic D, Dubska L, Valik D. Malignant Intracranial Germinoma in Smith-Lemli-Opitz Syndrome: Cholesterol Homeostasis Possibly Connecting Morphogenesis and Cancer Development. Journal of pediatric hematology/oncology 2008; 30(9):689-691.