The paternal copy in this region is deleted, while the maternal copy is inactivated by methylation.148,149 In addition, a genome-wide linkage analysis from African American, European American, and German populations identified several obesity-related genetic loci with differing parental effects or maternal effects.150 Furthermore, the pattern of DNA methylation at the human leptin promoter varies between alleles and cells, so it is possible that imprinting is locus and cell type specific. This evidence concerns the gene LEP and obesity due to melanocortin 4 receptor deficiency.