Expanded breeding genetic panel for the Maine Coon that brings together eleven molecular tests: blood group determination (CMAH), feline hypertrophic cardiomyopathy type 1 (MYBPC3 p.A31P), spinal muscular atrophy (TECPR2), pyruvate kinase deficiency (PKLR), polycystic kidney disease (PKD1), ivermectin sensitivity (MDR1/ABCB1), factor XII deficiency (F12), Duchenne muscular dystrophy (DMD), myotubular myopathy type 1 (MTM1), cystinuria type B and factor XI deficiency (F11). It combines cardiac, haematological, renal, neuromuscular and urological conditions and a blood group marker critical for neonatal isoerythrolysis. The panel is complementary to cardiac, blood and urological examination in breeding selection.

Maine Coon. Carrier frequencies vary between countries and lines. HCM1 is the most studied hereditary heart disease in the breed. PKD is documented in the breed through Persian introgression. Reliable carrier frequencies are not published systematically for the eleven conditions (limited data).

- Blood group: relevant for neonatal isoerythrolysis and transfusions\n- HCM1: left ventricular hypertrophy, risk of sudden death\n- SMA: spinal muscular atrophy, abnormal gait in kittens\n- PK: haemolytic anaemia of variable onset and severity\n- PKD: bilateral renal cysts, chronic kidney failure in adulthood\n- MDR1: neurotoxicity from ivermectin, loperamide, etc.\n- FXII: mild bleeding diathesis (often asymptomatic)\n- MD: progressive muscle weakness\n- MTM1: generalised hypotonia, muscle atrophy, breathing difficulty\n- Cystinuria: cystine stones in the bladder\n- FXI: mild bleeding diathesis

Each test in the panel was characterised independently. Feline blood group was associated with variants of the CMAH gene. HCM1 was associated with MYBPC3 p.A31P (Maine Coon). SMA was associated with the TECPR2 deletion (~140 kb). PK was associated with PKLR c.693+304G>A (Grahn 2012). PKD was associated with PKD1 c.10063C>A (Lyons 2004). The MDR-1 defect was associated with a deletion in ABCB1. Factor XII deficiency was associated with F12. Feline Duchenne muscular dystrophy was associated with DMD. Myotubular myopathy type 1 was associated with MTM1. Feline cystinuria type B has a molecular basis yet to be confirmed. Factor XI deficiency was associated with F11.

- Genotype breeding animals before mating (eleven tests on a single sample)\n- Blood group: identify type B queens before mating to prevent neonatal isoerythrolysis\n- For HCM1: carrier×clear with annual echocardiographic follow-up; incomplete penetrance\n- For SMA, PK, PKD, MDR1, MD, MTM1, cystinuria and FXI (recessive): do not mate two carriers — 25% of homozygotes affected; carrier×clear is safe if tested\n- For PKD (dominant): heterozygotes transmit the variant to 50% of the offspring; prioritise clear animals\n- After a confirmed clinical case, do not repeat the parental mating and communicate the status to the buyer

HCM1 is confirmed by echocardiography and molecular testing; annual examination is essential. SMA is suspected from abnormal gait in kittens and confirmed by testing. PK is diagnosed by complete blood count with reticulocytes and testing. PKD is confirmed by renal ultrasound in adults and molecular testing. MDR1 should be kept in mind when prescribing. FXII and FXI are diagnosed by coagulation profile. MD and MTM1 require muscle biopsy and testing. Cystinuria is diagnosed by stone analysis. Differentiate HCM1 from other cardiomyopathies and from arterial hypertension.

1. Meurs KM et al. 2005, MYBPC3 p.A31P en Maine coon (PMID 16236761)
2. Longeri M et al. 2013, penetrancia HCM1 (PMID 23323744)
3. Fyfe JC et al. 2006, TECPR2/SMA en Maine coon (PMID 16899656)
4. Grahn RA et al. 2012, PKLR en múltiples razas de gatos (PMID 23110753)
5. Lyons LA et al. 2004, mutación de la enfermedad renal poliquística felina identificada en PKD1 (PMID 15466259)
6. Mealey KL 2004, MDR1 (PMID 15500562)
7. Bighignoli B et al. 2007, CMAH y grupo sanguíneo AB felino (PMID 17553163)
8. OMIA:001440 SMA felina; OMIA:001298 prcd; OMIA:000807 PKD felina