USP6NL and early-onset autosomal dominant Alzheimer disease: For IBD, a significant association was identified by the FarmCPU method only and is located near the genes ECHDC3 and USP6NL. Neither of these genes are good candidates for a gastroenteropathy phenotype: in human GWAS studies, these genes have been associated with Alzheimer's disease (25, 56), and low-density lipoprotein (LDL) cholesterol (57).