Familial form of dilated cardiomyopathy of the Welsh springer spaniel associated with the R9H variant of the PLN gene (phospholamban). It produces left ventricular dilation and reduced contractility, progressing to heart failure, arrhythmias and risk of sudden death. The association is characterized in the breed and a specific genetic test exists.

The Welsh springer spaniel is listed as a breed predisposed to DCM in clinical series, but population frequencies are not reliably published. Limited data.

- Left ventricular dilation with low ejection fraction\n- Atrial and ventricular arrhythmias\n- Exercise intolerance and weakness\n- Cough and dyspnea due to congestive heart failure\n- Occasional syncope

Familial DCM of the Welsh springer spaniel was associated with a missense mutation (G>A) in exon 1 of the PLN gene that changes arginine to histidine at position 9 (R9H). Yost et al. (2019) described the variant in this breed as a spontaneous model of familial DCM with high penetrance and sudden death, modifiable by genetic or environmental factors. The variant is included in OMIA002195 and enables breeder status testing.

- Genotype breeding dogs for the PLN R9H variant before mating\n- Do not mate two carriers of the variant; breeding clinically affected animals is discouraged\n- Annual cardiac screening (echocardiography and Holter) of breeding dogs\n- Communicate the genetic status to the buyer

Differential diagnosis with nutritional and idiopathic DCM and with advanced degenerative valvular disease. Holter is useful for detecting preclinical arrhythmias. The PLN R9H variant is confirmed in the breed, so genetic testing complements phenotype and family history.

1. Yost O et al. 2019. The R9H phospholamban mutation is associated with highly penetrant dilated cardiomyopathy and sudden death in a spontaneous canine model. Gene 697:118-122. PMID: 30794913
2. OMIA:002195-9615 - Cardiomyopathy, dilated, PLN-related. https://omia.org/OMIA002195/9615/