Hypophosphatasia in Karelian bear dogs

Hypophosphatasia is a metabolic bone disease characterized by defective skeletal mineralization. It is manifested by growth retardation, seizures, movement difficulties and slowed psychomotor development.

The disease is caused by a missense mutation c.1301T>G in the ALPL gene, encoding alkaline phosphatase in liver, bones, and kidneys.

The mode of inheritance of the mutation is autosomal recessive. This means that only individuals who inherit the mutated gene from both parents will develop the disease. Carriers of the mutated gene are clinically healthy but pass the mutation on to their offspring. In the case of a mating between two heterozygous individuals, theoretically 25% of the offspring will be completely healthy, 50% of the offspring will be carriers and 25% of the offspring will inherit the mutated gene from both parents and will therefore be affected by the disease.

The genetic test can clearly reveal the genotype of the animal and is a useful tool for breeders to prevent unintentional breeding of affected puppies.

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References:

Kyöstilä, K., Syrjä, P., Lappalainen, A.K., Arumilli, M., Hundi, S., Karkamo, V., Viitmaa, R., Hytönen, M.K., Lohi, H. : A homozygous missense variant in the alkaline phosphatase gene ALPL is associated with a severe form of canine hypophosphatasia. Sci Rep 9:973, 2019. Pubmed reference: 30700765