Biochemical and Phenotypical Aspects of Smith-Lemli-Opitz Syndrome and Related Disorders of Cholesterol Metabolism

* INCLUSION CRITERIA: Males or females of any age with any one of the following: * Clinical, biochemical, or genetic diagnosis of Smith-Lemli-Opitz Syndrome OR * Clinical, biochemical, or genetic diagnosis of desmosterolosis, lathosterolosis, CHILD syndrome, X-linked dominant chondrodysplasia type2 or another inborn error of cholesterol synthesis OR * Clinical suspicion of an inborn error of cholesterol synthesis, metabolism or impaired cholesterol homeostasis. Clinical observations may include, but are not limited to lipid-laden macrophages, abnormal LDL, HDL, total cholesterol, triglycerides, abnormal lipid electrophoresis, lipid storage in other tissues. OR -Biologic parents of affected individuals or known carriers based on previously done genetic testing who are willing and able to provide samples of any or all of the following: blood, urine, a skin biopsy, and/or tissue derived from clinically indicated surgery or autopsy. EXCLUSION CRITERIA: * Affected individuals who cannot travel to the NIH because of their medical condition will be excluded from on-site participation. They may participate in the telemedicine or in the biomaterials parts of the study. * Affected individuals who, in the opinion of the investigator, are unable to comply with the protocol or have medical conditions that would potentially increase the risk of participation will be excluded from on-site participation. They may participate in the telemedicine or in the biomaterials parts of the study. * Carrier adults who are unable to or unwilling to provide any of the following samples: Blood, urine, skin biopsy sample or tissue derived from clinically indicated surgery or skin biopsy. * Female participants who are pregnant will be excluded from evaluations requiring sedation, radiation and LP. Total blood draw volumes will be kept at a minimum or if anemia of pregnancy is known, no blood will be taken for research testing.