We tested the GC IDMS method and the LC IDMS method for the possible interference of 7-dehydrocholesterol
, 5[alpha]-cholest-7-en-3[beta]-ol (lathosterol), lanosterol, [beta]-sitoserol, ergosterol, cholest-4,6-dien-3-one, coprostan3-ol, 25-hydroxycholesterol, cholesterol-5[alpha],6[alpha]-epoxide, 4-cholesten-3-one, 5-cholesten-3-one, and dihydrocholesterol.
Patients have decreased concentrations of cholesterol in plasma and increased concentrations of the precursor 7-dehydrocholesterol
(cholesta-5,7-dien-3[beta]-ol; 7-DHC) and its isomer 8-dehydrocholesterol (cholesta-5,8-dien-3[beta]-ol; 8-DHC) in plasma, erythrocytes, cultured skin fibroblasts, amniotic fluid, and various tissues [4-8]--findings that suggest a block in reduction of the C-7 double bond [4, 5].
3] is formed in the skin from its precursor 7-dehydrocholesterol
after ultraviolet irradiation or is absorbed from the diet (2).
3]) is either ingested in the diet or synthesized in the skin from 7-dehydrocholesterol
through exposure to sunlight (60).
Animals synthesize 7-dehydrocholesterol
, the immediate precursor of cholesterol; absorption of ultraviolet B radiation (290-315 nm) leads to a rearrangement of the 5-7-dime in the B ring of 7-dehydrocholesterol
, causing ring breakage to form previtamin [D.
3]) produced in skin via a photochemical reaction with 7-dehydrocholesterol
(1); and ergocalciferol (vitamin [D.
SLOS is caused by a deficiency of the enzyme 7-dehydrocholesterol
reductase (EC 1.
Prenatal diagnosis of Smith-Lemli-Opitz syndrome is possible by measurement of 7-dehydrocholesterol
in amniotic fluid.
Campesterol, sitosterol, stigmasterol, desmosterol, lathosterol, 7-dehydrocholesterol
, and butylated hydroxytoluene were obtained from Sigma-Aldrich Chemie.
Vitamin D3 is made through the ultraviolet irradiation of 7-dehydrocholesterol
Ultraviolet activation of 7-dehydrocholesterol
in the epidermis is the predominant source of cholecalciferol or vitamin [D.
2], and 7-dehydrocholesterol
were purchased from Sigma-Aldrich, and hexadeuterated analogs [[d.