Team Smith Lemli Opitz and ( SLOS , MIM 27400 ) is an autosomal recessive disorder . It is characterized by mental retardation , altered facial appearance and numerous irregularities in the construction of many organs . The cause of many defects is a deficit activity of 7- dehydrocholesterol reductase ( DHCR7 ) , the enzyme that catalyzes the last step in the biosynthesis of cholesterol. Recently it was discovered that cholesterol plays a key role in embryonic development of the organism by regulating the activities of signal proteins ( sonic hedgehog , SHH ) .