Molecular heterogeneity for bovine maple syrup urine disease.

In Poll Herefords, it is known that maple syrup urine disease results from a nonsense mutation in codon -6 of the gene for the E1 alpha subunit of branched-chain alpha-keto acid dehydrogenase. The disease also occurs in Poll Shorthorns, but its molecular basis in this breed has not yet been determined. Allele-specific hybridization and allele-specific amplification, both based on the Poll Hereford mutation, failed to detect the mutant allele in Poll Shorthorn heterozygotes, and detected the normal allele in affected Poll Hereford-cross-Poll Shorthorn calves. These results demonstrate between breed molecular heterogeneity for bovine maple syrup urine disease.