Combined test evaluating two genetic risk variants for DCM in the Dobermann: DCM1 (PDK4 gene) and DCM2 (TTN gene, titin). Both increase the predisposition to a disease characterised by left ventricular dilatation, systolic dysfunction and, above all, ventricular arrhythmias that may precede mechanical failure. DCM is one of the main causes of death in the breed and the accumulated risk of both variants conditions the age of onset and severity. It is a complementary test, not a substitute, for clinical examination.

DCM is highly prevalent in the European Dobermann, with figures in some series exceeding 40-50% of the population over a lifetime. The allele frequencies of the DCM1 and DCM2 variants are relevant in European and American lines, although they vary between populations. Limited data for exact figures by country and line.

- Decreased left ventricular ejection fraction\n- Left ventricular dilatation\n- Complex ventricular arrhythmias and ventricular prematurity\n- Syncope and risk of sudden death\n- Exercise intolerance\n- Congestive heart failure with pulmonary oedema, dyspnoea and cough

The first DCM variant of the Dobermann (DCM1) was associated with the PDK4 gene through work by K. Meurs' group published in 2012: a 16-bp deletion in the splice donor site of intron 10, with dominant inheritance and a significant but incomplete effect on risk. In 2019, the same group identified the second variant (DCM2) in the titin gene (TTN), also with a dominant effect. Combining both tests improves the estimation of individual risk. Dobermann DCM is one of the best genetically studied in the species.

- Test every breeding animal before mating\n- Avoid mating two animals carrying the same variants, and especially double homozygotes\n- Prioritise breeding animals clear of both variants in selection\n- Genetic testing does not replace cardiological screening: annual echocardiography and Holter from adulthood\n- Communicate the status to buyers and maintain lifelong cardiological follow-up

Differential diagnosis with nutritional DCM (taurine deficiency, more relevant in some diets) and with arrhythmogenic cardiomyopathy. The 24-h Holter is the most sensitive tool for detecting the preclinical arrhythmic phase. Genetic result interpretation must be probabilistic: the presence of variants indicates increased risk, not certain disease; their absence does not guarantee a healthy heart.

1. Meurs KM et al. 2012, A splice site mutation in a gene encoding for PDK4, a mitochondrial protein, is associated with the development of dilated cardiomyopathy in the Doberman pinscher. Hum Genet 131(8):1319-25. PMID: 22447147. 2. Meurs KM et al. 2019, A missense variant in the titin gene in Doberman pinscher dogs with familial dilated cardiomyopathy and sudden cardiac death. Hum Genet 138(5):515-524. PMID: 30715562. 3. Meurs KM et al. 2020, Assessment of PDK4 and TTN gene variants in 48 Doberman Pinschers with dilated cardiomyopathy. J Am Vet Med Assoc 257(10):1041-1044. PMID: 33135971. OMIA:000162-9615.