Possibly relevant human trait(s) and/or gene(s) (MIM number): 605792 (gene)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal Recessive

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2011

Species-specific description: As reported by Sironen et al. (2011), this disorder is characterised by "severe degeneration of germ cells and total absence of spermatozoa".

Mapping: From a genome-wide scan conducted with markers on the PorcineSNP60 Beadchip, Sironen et al. (2011) mapped this disorder to a 2 Mb region on chromosome SSC12.

Molecular basis: As reported by Sironen et al. (2011), the 2 Mb region on SSc12 contained the gene TEX14, which was a strong candidate because mice in which this gene has been knocked out have a very similar phenotype to affected pigs. Sequencing of this gene in affected pigs "revealed a 51 bp insertion within exon 27, which caused differential splicing of the exon and created a premature translation stop codon. The expression of Tex14 was markedly down regulated in the testis of a SA affected boar compared to control boars and no protein product was identified by Western blotting."

Clinical features: The disorder was first reported by Kopp et al. (2008). In the words of Sironen et al. (2011), "The testicular size appeared to be approximately half of the normal size in affected boars and microscopical examination of the ejaculate revealed total absence of spermatozoa . . . . Further histological examination of the . . . affected testis sections showed markedly reduced number of late meiotic cells and absence of postmeiotic cells . . . . Furthermore, affected testes displayed severe degeneration of germ cells and vacuolization probably due to increased germ cell apoptosis".

Breeds: Finnish Landrace, Finnish Yorkshire.

Associated gene: