Hereditary cardiomyopathy of the Belgian Shepherd that causes juvenile mortality. It produces early heart failure with myocardial dilatation and dysfunction, and affected puppies die in the first weeks or months of life. It is a severe, incurable entity, distinct from the cardiomyopathies of the adult dog.

Carrier frequency of 27,2 % in tested Belgian Shepherds (Gurtner et al. 2020). Rare disease; limited data on its distribution by variety.

- Congestive heart failure in the puppy\n- Weakness and lethargy\n- Exercise intolerance and food refusal\n- Respiratory difficulty and tachypnoea\n- Cough and pulmonary oedema\n- Death before 6 months of age in severe forms

Cardiomyopathy with juvenile mortality (CJM) of the Belgian Shepherd was described in a cohort of puppies with sudden death. Gurtner et al. (2020) associated the disease with a missense variant of YARS2 in the tRNA-binding domain, with consistent association in a cohort of Belgian Shepherds and a carrier frequency of 27,2 %.

- Genotype Belgian Shepherd breeding animals (YARS2 c.1054G>A) before mating.\n- Do not cross carrier×carrier (25 % homozygotes with juvenile mortality).\n- Carrier×clear does not produce affected animals; test the offspring intended for breeding.\n- Record sudden deaths of puppies under 8 weeks of age to characterise the cohort.

Differential diagnosis with other cardiomyopathies of the young (taurine deficiency, myocarditis, congenital heart disease). Echocardiography shows dilatation and dysfunction; the clinical presentation and age guide the diagnosis. Heart failure management; the prognosis of severe forms is poor.

1. Gurtner C et al. 2020, variante missense de YARS2 en pastores belgas con cardiomiopatía y mortalidad juvenil (PMID 32183361)
2. OMIA:002256 CJM (YARS2)