Novel genetic variants of the G protein-coupled Receptor Similar To The Adrenomedullin Receptor (ADMR) gene are described. Various genotypes, haplotypes, and haplotype pairs that exist in the general United States population are disclosed for the ADMR gene. Compositions and methods for haplotyping and/or genotyping the ADMR gene in an individual are also disclosed. Polynucleotides defined by the haplotypes disclosed herein are also described.