Elevated serum concentration of anti-Mullerian hormone and its association with SNP variants in the AMH gene in a tortoiseshell tomcat with a disorder of sex development (38,XX; SRY-negative)

Abstract

Testicular disorders of sex development (DSD) in cats with XX sex chromosomes and the absence of the SRY gene are rare congenital abnormalities. A Maine Coon tomcat with a normal penis, gonads in the scrotum, low serum testosterone concentration, and an elevated level of anti-Müllerian hormone (AMH) was subjected to genetic analyses due to an unusual tortoiseshell coat color for males. Primary studies revealed the presence of XX sex chromosomes, the lack of SRY and the presence of two copies of the candidate SOX9. The DSD tomcat and its parents were analyzed using whole genome sequencing. Candidate SNPs in AMH, ORC1, DOCK8, PRKAR1A, and TMEM186 genes, as well as a known intronic 5-kb deletion in X-linked ARHGAP36 gene, which is responsible for orange coat, were identified. Potentially pathogenic homozygous genotypes were observed in all candidate genes; however, only in AMH and ORC1 were these genotypes rare in a control cohort. Further studies were focused on two SNPs located in the 5′-and 3′-untranslated regions (UTRs) of AMH. It has been experimentally demonstrated that only a short AMH transcript is present in feline testes. In silico analysis revealed that the SNP located in the 3′UTR of AMH occurs within a sequence that partially matches the canonical binding site for human miR-5571-5p. This microRNA is expressed in mammalian testes, which we confirmed in feline testicular tissue. We concluded that SNP in the 3′UTR of AMH is associated with elevated expression of the encoded hormone; however, it is not the cause of the testicular DSD phenotype in the studied Maine Coon tomcat.