In other species: dog

Categories: Hearing / vestibular / ear phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 276900 (trait) , 600060 (trait) , 601317 (trait) , 276903 (gene)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal recessive

Disease-related: yes

Key variant known: yes

Year key variant first reported: 2021

Species-specific description: Derks et al. (2021) "examined a commercial synthetic Duroc population for recessive defects and identified a haplotype ... affecting pre-weaning mortality."

Mapping: Derks et al. (2021) "examined 14 160 (10 402 boars, 3758 sows) genotyped animals (Porcine 50K SNP chip) from a synthetic Duroc population.... and identified a haplotype on chromosome 9 significantly affecting pre-weaning mortality."

Molecular basis: Derks et al. (2021): "To identify the causal variant underlying the mortality, we examined sequence data of four carrier animals and 21 non-carrier animals from the same population. The results yield a strong candidate causal stop-gained variant (NM_001099928.1:c.541C>T) affecting the MYO7A gene in complete linkage disequilibrium with the lethal haplotype. The variant leads to an impaired (p.Gln181*) MYO7A protein that truncates 2032 amino acids from the protein."

Clinical features: Derks et al. (2021) "examined 31 past carrier-by-carrier litters and observed a significant 23% decline in pre-weaning survival ... . The 31 litters produced a total of 316 piglets (281 born alive ...). From the 281 piglets born alive, 81 did not survive the lactation period (29% ...). Sixty-six out of 81 died within the first 5 days, while some lived until the end of the lactation period. However, it is not clear whether the animals that lived until the end of the lactation period (23 days) were homozygous for the haplotype. In addition, from 38 piglets (that died during the lactation period), a cause of death was submitted into the system. For 24 out of 38 piglets that died early from the carrier-by-carrier crosses ‘nervous disease’ was marked as the cause of death ... . Nervous disease is generally indicated when the piglets have difficulty maintaining balance, and show ‘shaky’ behaviour ... . We examined a carrier-by-carrier litter ... . The litter resulted in 11 born alive piglets and one still born. Two piglets died 2 days later ... and both piglets showed nervous system issues, i.e. shaking behaviour, difficulties maintaining balance, and difficulty walking .... The whole litter was genotyped ... . Both ‘shaky’ piglets were homozygous for the haplotype on chromosome 9. From the remaining nine littermates, five were heterozygous for the haplotype and four were non-carriers (including the stillborn piglet ...). ... We tested whether the carrier sow ... reacted to noise and observed that the sow did not react to sound at all, but she was definitely not blind (she responded to visual stimuli). The onset of deafness could not be determined and needs further investigation."

Prevalence: "The variant segregates at a carrier frequency of 8.2% in the evaluated population" (Derks et al. 2021)

Breed: Duroc (Pig) (VBO_0001127).
Breeds in which the phene has been documented. (If a likely causal variant has been documented for the phene, see the variant table breeds in which the variant has been reported).

Associated gene: