Ichthyosis in Great Danes

Ichthyosis is an inherited skin disease that is manifested by scaling, cornification and peeling of the top layer of the skin. In Great Danes, the signs of the disease are visible immediately after birth. Puppies have scaly, thickened, and wrinkled skin which is most severe around the eyes and the nose. Typical white to yellowish scales can be seen all over the body. The exudative nature of the skin leads to infections and secondary inflammation.

In Great Danes, the disease is caused by a mutation in the SLC27A4 gene. This is a single nucleotide substitution in exon 8, c.1250G>A, which alters the sequence of the encoded amino acid (p.Arg417Gln).

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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Reference:

Metzger, J., Wöhlke, A., Mischke, R., Hoffmann, A., Hewicker-Trautwein, M., Küch, E.M., Naim, H.Y., Distl, O. : A novel SLC27A4 splice acceptor site mutation in Great Danes with ichthyosis. PLoS One 10:e0141514, 2015. Pubmed reference: 26506231