I haven't bred a litter since late 2007, after which I desexed all of my cats. As a result I've lost track of their ancestors without actually going back to their pedigrees to look.
So. Late last year I discovered that a cat named Jomai Blue Ben is a known carrier of ARVC - Arrythmogenic Right Ventricle Cardiomyopathy. This disease is a pretty rare form of cardiomyopathy, and unlike its more common relative Hypertrophic Cardiomyopathy it is sometimes seen in Birman lines. I also learned the symptoms of the disease, and they fit perfectly with the symptoms suffered by a cat of mine that died in 2003 aged 5. That cat had Ben in her pedigree, only two gens back. I still have that cat's sister, Ratty; she's now 14 years old and apart from the odd liver complaint she's perfectly healthy. I think. I also have three of Ratty's daughters. All of them are suspect but so far all are healthy.
Late December my ex-stud Tang went off his feed, and vet discovered he had a heart murmur. That wasn't the problem, though, and after a course of antibiotics he came good again. Until early January, when I came home from work one day and discovered he'd passed. Checking his pedigree, I discovered that he too had Jomai Blue Ben two gens back. Which means that my Princess Fatty Kitten (pictured in icon) has a double whammy, as she is Ratty and Tang's daughter.
Then today I was filling out a show entry form; first time I've entered Chicken in a show for about four years. I had to include a copy of her pedigree, and there was Blue Ben in her lines as well. I had thought she was totally unrelated to my other cats but seems not :-( . And to make matters worse - her pedigree shows that Blue Ben was the father of a cat named The Sheik, who just happens to be my Little Dot's father. As Ratty is Dot's mother, she also has the double whammy.
What this means is the only Birman I have who isn't related to Blue Ben is my 17 year old Miss Kissy. However, I lost both her brother and her mother about 12 years ago after saddle clots paralysed their back legs. At the time my vet thought that the clots could have been related to cardiomyopathy but he was looking for the commoner hypertrophic type, not ARVC. So it's possible that he missed it. Still, Kissy is going strong and I don't think she's at risk.
It's really, really disheartening. I always thought that I'd take up breeding again once I retired and had time to spend with kittens (and to that end I've kept my breeder's licence current), but if the disease is so widespread I don't know that I'd want to; at least not with Birmans. Maybe a different breed? I love the Norwegians as well but some lines there have hip problems. Siamese are gorgeous, and I've owned a Meezer before who utterly charmed me - it might be nice to breed and show shorthaired cats for a change. But I love the Birman breed so much; their temperament, their personalities, and their looks, all add up to a wonderful cat. It would take a bit of searching, though, to find cats who are totally unrelated to Ben (and another known carrier) because if you go back far enough, about 80% of the Birmans in this country today can be traced back to the original imports in the late 60s.