Novel single nucleotide polymorphisms in the human IMP dehydrogenase 2 (IMPDH2) gene are described. In addition, various genotypes, haplotypes and haplotype pairs for the IMPDH2 gene that exist in the population are described. Compositions and methods for haplotyping and/or genotyping the IMPDH2 gene in an individual are also disclosed. Polynucleotides containing one or more of the IMPDH2 polymorphisms disclosed herein are also described.
