Testing of dogs: SACS
Related tests
- Combination Pyrenean Mountain Dog (Great Pyrenees) CMR1 + DM (SOD1A) + SACS + Thrombasthenia
Neuronal degeneration associated with SACS gene in Great Pyrenees dogs
The nervous system disorder has been reported in Great Pyrenees dogs and is characterised by degeneration of the central nervous system that leads to progressive cerebellar ataxia (movement coordination disorder) and spasticity (condition with increased muscle tone).
The clinical symptoms appear very soon at the age of 4 months and sometimes even earlier. The disease gradually progresses during next several years and the symptoms get worse. The affected dogs have abnormal gait - clumsy or uncoordinated movement with a wide-base stance, slipping and sliding manoeuvring particularly on smooth surfaces. The loss of coordination results in intermittent falling that might cause painful injury. Climbing up and down stairs presents generally a problem.
The loss of control over body movements is caused by pathological changes in the nervous system. Due to the mutation in SACS-gene that takes part in the regulation of mitochondrial dynamics it comes to progressive neuron degeneration and loss of cerebellar Purkinje cells. The 4-bp deletion in exon 9 of SACS-gene causes a shift in the reading frame and shortening of mRNA.
Mutation that causes neuronal degeneration associated with SACS gene in Great Pyrenees dogs is inherited as an autosomal recessive trait. That means the disease affects dogs with P/P (positive / positive) genotype only. The dogs with P/N (positive /negative) genotype are clinically without any symptom. They are genetically considered carriers of the disease (heterozygotes). In offspring of two heterozygous animals following genotype distribution can be expected: 25 % N/N (healthy non-carriers), 25 % P/P (affected), and 50 % N/P (healthy carriers). Because of high risk of producing affected offspring, mating of two N/P animals (carriers) can not be recommended.
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References:
Kari J Ekenstedt, Katie M Minor, G Diane Shelton, James J Hammond, Andrew D Miller, Susam M Taylor, Yanyun Huang, Michael Pawlik, James R Mickelson: A Spontaneous Canine Model of SACS-Associated Neuronal Degenweration; The 9th international conference on canine and feline genetics and genomics