British Shorthair — questions to ask before paying a deposit
A responsible breeder will have these readily available. Deflection is a red flag.
Hypertrophic cardiomyopathy (HCM)can shorten life or cause chronic pain
A peer-reviewed cohort study screening 329 British Shorthairs presented for routine HCM screening in Denmark found a clinically significant prevalence of the disease in the breed, independent of the two known commercial feline HCM mutations. No breed-specific causal mutation has been identified in British Shorthair.
Ask to see: No DNA test exists for British Shorthair HCM. The two commercial feline HCM DNA tests (MYBPC3 A31P, validated for Maine Coon; MYBPC3 R820W, validated for Ragdoll/Ragamuffin) are breed-specific and are not validated in British Shorthair. Screening is by echocardiogram performed by a cardiologist, repeated periodically through breeding life.
Prevalence of Hypertrophic Cardiomyopathy in a Cohort of British Shorthair Cats in Denmark, Journal of Veterinary Internal Medicine, via PubMed (https://pubmed.ncbi.nlm.nih.gov/21736622/) · Cat DNA tests -- breed and test listing (confirms no HCM variant test is offered for British Shorthair), UC Davis Veterinary Genetics Laboratory (https://vgl.ucdavis.edu/species/cat)
Neonatal isoerythrolysis risk (blood type B)
British Shorthair is named by UC Davis VGL as one of the breeds with a high frequency of the blood type B allele. A type B queen mated to a type A or AB tom risks producing kittens that develop neonatal isoerythrolysis (a fatal or life-threatening haemolytic reaction) after nursing colostrum containing anti-A antibodies.
Ask to see: AB blood typing test (UC Davis VGL and other labs). Both breeding partners should be blood-typed before pairing so an at-risk mating can be avoided or managed (e.g. foster-nursing kittens for the first 24-48 hours).
Feline AB Blood Type test -- notes British Shorthair among breeds with high blood type B frequency, UC Davis Veterinary Genetics Laboratory (https://vgl.ucdavis.edu/species/cat)