OMIA 000698-9940 : Myotonia in Ovis aries

In other species: goat , dog , domestic cat , horse , cattle , water buffalo

Possibly relevant human trait(s) and/or gene(s) (MIM number): 160800

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal Recessive

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2015

Molecular basis: Using a comparative candidate gene approach (based on the same clinical signs being due to mutations in CLCN1 in goats, horse and humans [see related entries at the top of this page]), Monteagudo et al. (2015) sequenced this gene in two affected lambs and three unrelated unaffecteds from Spanish flocks of the Rasa Aragonesa breed. They reported "In the second exon, a g.106140081G>A transversion was found in homozygosity in both affected individuals (GenBank number NC_019461.1 numbering), resulting in a p.Gln93Lys substitution in the amino acid sequence. Both lambs were born from ewes heterozygous for this SNV (GA), verified by DNA sequencing. Five of the 27 rams in service at the farm were also found to be heterozygous GA, while the remainder was homozygous GG. No AA individuals were detected among the adult individuals." 40 unrelated rams from other flocks were homozygous GG. Importantly, "Removing the GA rams in May 2013 and replacing them with GG rams from the same flock allowed us to prevent occurrence of homozygous AA new-born lambs in the flock and to confirm association between the SNV [single nucleotide variant] and the pathology. As of 22 December 2014, no additional affected lambs had been born, further supporting the role of this SNV in the pathology."

Clinical features: As reported by et al. (2015) "The symptoms were visible only after sudden visual and/or auditory stimulation or fast movements during normal flock management. When other individuals in the lot started evasive movements, the affected lambs maintained a rigid position with extended limbs and frequently fell to the ground. After 6–25 s, the lambs were able to stand and move normally."

Breed: Rasa Aragonesa.

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
CLCN1 chloride channel, voltage-sensitive 1 Ovis aries 4 NC_019461.2 (106110190..106146932) CLCN1 Homologene, Ensembl, NCBI gene

Variants

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Breed(s) Variant Phenotype Gene Allele Type of Variant Reference Sequence Chr. g. or m. c. or n. p. Verbal Description EVA ID Year Published PubMed ID(s) Acknowledgements
Rasa Aragonesa Myotonia CLCN1 missense p.Q93K 2015 25744800

References


Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.
2015 Monteagudo, L.V., Tejedor, M.T., Ramos, J.J., Lacasta, D., Ferrer, L.M. :
Ovine congenital myotonia associated with a mutation in the muscle chloride channel gene. Vet J 204:128-9, 2015. Pubmed reference: 25744800. DOI: 10.1016/j.tvjl.2015.01.014.
1997 Moore, G.A., Dyer, K.R., Dyer, R.M., Sponenberg, D.P. :
Autosomal recessive myotonia congenita in sheep Genetics Selection Evolution 29:291-294, 1997.

Edit History


  • Created by Frank Nicholas on 06 Sep 2005
  • Changed by Frank Nicholas on 08 Mar 2015