Cerebellar Abiotrophy

 

Genes: MUTYH, TOE1 genes

Transmission: Autosomal recessive

For an autosomal recessive genetic disease an animal must have two copies of the mutation in question to be at risk of developing the disease.  Both parents of an affected animal must be carriers of at least one copy of the mutation.  Animals that have only one copy of the mutation are not at risk of developing the disease but are carrier animals that can pass the mutation on to future generations.

Mutation: Substitution, MUTYH gene; c.-1200 G>A (and TOE1; G>A exon4)

Breeds: Arabian, miniature horse, Gotland, Eriskay, Oldenbourg

Age of onset of symptoms: 6 weeks to 3 months of age

Cerebellar Abiotrophy (CA) is a neurological disease seen in Arabian horses as well as in a few other breeds.  The disease is characterized by postnatal degeneration of Purkinje cells in the cerebellum; these cells are involved in coordination of movement.  Most foals appear normal at birth and symptoms become evident around four months of age.  The clinical signs are those of cerebellar dysfunction and they include ataxia, head tremors, a lack of balance and coordination and a general lack of awareness of body position and movement (proprioception).  In theory, horses could live with this disease, however, they will not be useful for sporting events and are at risk of having accidents.

 

References:

OMIA link: [0175-9796]

Ayad, A, Almarzook, S, Besseboua, O, et al. (2021) Investigation of Cerebellar Abiotrophy (CA), Lavender Foal Syndrome (LFS), and Severe Combined Immunodeficiency (SCID) Variants in a Cohort of Three MENA Region Horse Breeds. Genes (Basel) 12:1893. [pubmed/34946842]

Bugno-Poniewierska M, Stefaniuk-Szmukier M, Piestrzyńska-Kajtoch AP, et al. (2019) Genetic screening for cerebellar abiotrophy, severe combined immunodeficiency and lavender foal syndrome in Arabian horses in Poland. Vet J 248:71-73. [pubmed/31113566]

Scott EY, Woolard KD, Finno CJ, Penedo, MCT, Murray JD. (2018) Variation in MUTYH expression in Arabian horses with Cerebellar Abiotrophy. Brain Res 1678:330-336. [pubmed/29103988]

Scott EY, Penedo MCT, Murray JD, et al. (2017) Defining Trends in Global Gene Expression in Arabian Horses with Cerebellar Abiotrophy.  Cerebellum. 16(2):462-472. [pubmed/27709457]

Tarr CJ, Thompson PN, Guthrie AJ, et al. (2014) The carrier prevalence of severe combined immunodeficiency, lavander foal syndrome and cerebellar abiotrophy in Arabian horses in South Africa.  Equine Vet Journal 46:512-514. [pubmed/24033554]

Brault LS, Cooper CA, Famula TR, et al. (2011) Mapping of equine cerebellar abiotrophy to ECA2 and identification of a potential causative mutation affecting expression of MUTYH.  Genomics 97:121-129. [pubmed/21126570]

Brault LS, Pemedo MCT, (2011) The frequency of the equine cerebellar abiotrophy mutation in ino-Arabian horse breeds.  Equine Vet Journal 43(6):727-731. [pubmed/21496100]