Dwarfism in Dalmatians

Dwarfism is a disease characterized by disproportionate stunted growth - disproportionately short limbs and changes in body structure. The disease causes a slowdown or incorrect maturation of cartilage and premature closure of growth plates. Symptoms are already visible in puppies and include gait abnormalities, short legs and curved front legs with outward-angled elbow joints.

In Dalmatians, this defect is caused by a nonsense mutation c.1601T>G in the PRKG2 gene. The PRKG2 gene encodes a cGMP-dependent protein kinase that controls the correct ossification of cartilage cells during bone growth.

The mutation is inherited in an autosomal recessive manner. This means that the disease only develops in individuals who inherit the mutated gene from both of their parents. Carriers of the mutated gene are of normal height, but they pass the mutation on to their offspring. In the case of mating two heterozygous individuals, theoretically 25% of the offspring will be clear (without the mutation), 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 this defect.

A genetic test can clearly reveal the genotype of the animal and is a suitable tool for breeders to prevent the unintentional reproduction of affected puppies.

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Reference:

Mäkeläinen, S., Ekman, S., Hytönen, M.K., Lohi, H., Kyöstilä, K., Simon, T., Andersson, G., Hedhammar, Å., Hansson, K., Bergström, T.F. : A nonsense mutation in the PRKG2 gene in dalmatian dogs with chondrodysplasia. PLoS One 20:e0322107, 2025. Pubmed reference: 41296694