Importantly, mutations in the NSDHL gene in humans have been linked to an X-linked dominant condition called CHILD syndrome (‘congenital hemidysplasia with ichthyosiform erythroderma and limb defects’, reviewed in Herman, 2000) that is usually lethal in males (Bornholdt et al., 2005). The gene discussed is NSDHL; the disease is congenital non-bullous ichthyosiform erythroderma.