DHCR24 and early-onset autosomal dominant Alzheimer disease: As a key regulator of cellular cholesterol synthesis, DHCR24 was found to be downregulated in Alzheimer’s disease (AD) vulnerable regions and involved in AD-related pathological activities [16], and DHCR24 reverses AD-related pathology and cognitive impairment by increasing cholesterol levels in the hippocampus of 5xFAD mice [17].