Summary
Lathosterolosis is an inborn error of cholesterol biosynthesis caused by 3-beta-hydroxysteroid-delta-5-desaturase (SC5D) deficiency and associated with malformations, intellectual deficit and liver disease. Lathosterolosis has been observed in two patients. One was a girl with multiple congenital anomalies, including severe microcephaly, facial dysmorphism, postaxial hexadactyly of the left foot, syndactyly between the 2nd and 4th toes and between the 5th toe and the extra digit, severe psychomotor delay, axial hypotonia, and liver disease. The second case of lathosterolosis was retrospectively identified by a biochemical characterization of cultured fibroblasts from a deceased patient. This patient had corneal clouding, gingival hypertrophy, bilateral post-axial polydactyly, syndactyly of toes two and three, hepatosplenomegaly, genital anomalies, and neurologic manifestations, including myoclonus, white matter demyelination and cerebral calcifications. Studies of cholesterol biosynthesis in cultured fibroblasts showed that the disease is caused by a metabolic block in the conversion of lathosterol into 7-dehydrocholesterol. Assay of SC5D in cultured fibroblasts revealed deficient enzyme activity and molecular analysis identified mutations in the SC5DL gene. The diagnosis of lathosterolosis is based on the demonstration of increased lathosterol levels in plasma and cells by gas chromatography-mass spectrometry. Prenatal diagnosis is feasible. *Author: Dr G. Parenti (February 2005)*.
