A genetic variant in the thyroperoxidase gene causes primary congenital hypothyroidism in cats. Affected cats show dysproportional dwarfism.

In some cats the growth retardation is obvious, while in others it is less noticeable. Other signs may include goiter with bilateral enlargement of both lobes of the thyroid gland, mental sluggishness, constipation and delayed tooth eruption. Serum total T4 concentrations are in a low to low-normal range, while TSH concentrations are abnormally high. Congenital hypothyroidism is usually diagnosed at a young age. Supplementation with L-T4 leads to a clinical improvement as well as to an increase in serum T4 and a decrease in TSH concentrations.

Are you interested in the genetic make-up of your cat? Congenital hypothyroidism is now also included in the comprehensive LABOGenetics XXL Cat combination. Over 50 genetic variants are being studied here. You will receive information on hereditary diseases, genetic risk factors, coat colours and coat characteristics. The determination of the genetic blood group is, of course, also included. LABOGenetics XXL Cat is available for cats of all breeds and mixes.

Hypertrophic cardiomyopathy (HCM) is the most common heart disease in cats and leads to reduced resilience. The diagnosis is made by means of an ultrasound examination (echocardiography), which can be supported by a genetic test. Clinical symptoms can appear as early as 3 months of age, the average age of onset is around 6.5 years.

The first sign of HCM is a thickening of the wall (concentric hypertrophy) of the left ventricle. Other parts of the heart can also be altered, e.g. the papillary muscles and the left heart valve (mitral valve). Eventually, the left ventricle becomes enlarged.

In a new study by Boeykens et al. In 2024, the six known genetic variants from four different genes associated with HCM in domestic cats were investigated. The genetic variants are divided into 5 categories: pathogenic, probably pathogenic, unknown significance, probably benign and benign. For clinical diagnostics and for use as a genetic test, it is recommended that only variants from the first two categories are used. The study took into account screening results from more than 10,000 cats.

The MYBPC3:c.91G > C [A31P] variant occurs mainly in the Maine Coon, while it occurs randomly in other breeds and may have become rarer through selection. Labogen offers this variant as the HCM1 test.

The MYBPC3:c.2453C > T [R818W] variant was only found in Ragdoll cats or in breeds where crossbreeding with Ragdolls could have been part of the breeding development. This test is also offered by Labogen and is known as HCM3.

No evidence of causation of the disease was found for the other variants in the study, which speaks against screening for these variants.

Labogen offers an additional HCM variant in the Sphynx for testing, which was recently published (ALMS1:c.7384G > C [G2462R]). Although the aforementioned study could not confirm the link to HCM, the original publication linked mutations in this gene to the development of Alstrom syndrome, a familial multisystem disorder that can include (dilated, restrictive) cardiomyopathy. The variant alters the protein structure, which can be associated with HCM.