INSENSITIVITY TO ANTI-MULLERIAN HORMONE DUE TO A MUTATION IN THE HUMAN ANTI-MULLERIAN HORMONE-RECEPTOR

Anti-Mullerian hormone (AMH) and its receptor are involved in the regression of Mullerian ducts in male fetuses. We have now cloned and mapped the human AMH receptor gene and provide genetic proof that it is required for AMH signalling, by identifying a mutation in the AMH receptor in a patient with persistent Mullerian duct syndrome. The mutation destroys the invariant dinucleotide at the 5' end of the second intron, generating two abnormal mRNAs, one missing the second exon, required for ligand binding, and the other incorporating the first 12 bases of the second intron. The similar phenotypes observed in AMH-deficient and AMH receptor-deficient individuals indicate that the AMH signalling machinery is remarkably simple, consisting of one ligand and one type II receptor.