This suggests that almost all the phenotypes observed with humans with desmosterolosis may be as a result of embryonic loss of DHCR24 activity and that loss of DHCR24 postnatally may not be as detrimental; loss of Dhcr24 in mice using a globally expressed ER-cre driver resulted in the absence of endogenous cholesterol synthesis and a dramatic elevation in desmosterol levels but was well tolerated. This evidence concerns the gene DHCR24 and desmosterolosis.