Smith-Lemli-Opitz Syndrome

Clinical Characteristics
Ocular Features: 

A large number of ocular anomalies have been found in SLO syndrome but the most common is blepharoptosis of some degree.  No consistent pattern of ocular abnormalities has been reported.  Atrophy and hypoplasia of the optic nerve, strabismus, nystagmus, and cataracts may be present.   Abnormally low concentrations of cholesterol and cholesterol precursors have been found in all ocular tissues studied.

Systemic Features: 

This is a syndrome of multiple congenital anomalies.  Among these are dwarfism, micrognathia, hard palate anomalies, hypotonia, anomalies of the external genitalia, polysyndactyly, microcephaly, and mental retardation.  It has been suggested that many individuals have a characteristic behavioral profile consisting of cognitive delays, hyperreactivity, irritability, language deficiency, and autism spectrum behaviors.  Some individuals exhibit aspects of self destructive behavior.  Tissue levels of cholesterol are low.


SLO syndrome is an autosomal recessive disorder resulting from mutations in the sterol delta-7-reductase  (DHCR7) gene mapped to 11q12-q13. The result is a defect in cholesterol synthesis.

The clinical features significantly overlap those seen in Meckel (249000) and Joubert (213300) syndromes.

Treatment Options: 

A high cholesterol diet has been reported to have a beneficial effect on behavior and general well-being.

Article Title: 


Atchaneeyasakul LO, Linck LM, Connor WE, Weleber RG, Steiner RD. Eye findings in 8 children and a spontaneously aborted fetus with RSH/Smith-Lemli-Opitz syndrome. Am J Med Genet. 1998 Dec 28;80(5):501-5.

PubMedID: 9880216

Irons M, Elias ER, Abuelo D, Bull MJ, Greene CL, Johnson VP, Keppen L, Schanen C, Tint GS, Salen G. Treatment of Smith-Lemli-Opitz syndrome: results of a multicenter trial. Am J Med Genet. 1997 Jan 31;68(3):311-4.

PubMedID: 9024565

Cunniff C, Kratz LE, Moser A, Natowicz MR, Kelley RI. Clinical and biochemical spectrum of patients with RSH/Smith-Lemli-Opitz syndrome and abnormal cholesterol metabolism. Am J Med Genet. 1997 Jan 31;68(3):263-9.

PubMedID: 9024557