Not nuclear but just plain ol' WV inbreeding.

His father is likely a son of his mother's brother. Does that make sense? His grandfather has the gene for this mutation, though he doesn't have polydactyl, he has a weird displacement of the 1st toe that makes it look like he has thumbs. Most of his offspring with his sister as his mate also has this trait and some have an extra toe in the gap of that spacing.
Now, it's commonly thought that polydactyl cats also have the mutation for a bob tail but none of his offspring have such a thing.
You'd love this kitten....he's kind of stolen my heart a bit. He's adventurous and funny, pretends he wants to play with you but shies away if you advance towards him. He can't be loved into purring but he'll dart into the house if he gets a chance, just to nose around. He looks for me and walks out to greet me, but doesn't really want me to pick him up....then he'll flop down in front of a sheep like he wants her to pet his belly. He's a real trip!
He's half the size of his mother and is still nursing, so he's fat as a tick. He stalks the chickens but when they notice he acts all nonchalant like he's not up to anything.
Can't wait to see what kind of story he writes, as it's starting out really cute.
I wish I had known you wanted some Poly kitties....I gave three of his siblings to a young girl who is starting a cat rescue and didn't have any cats to rescue at the time. One of those had an extra toe on each front paw, though not quite as perfectly placed as Ruffle's are. Her extra toes were tiny with just a claw showing.
Getting Molly fixed, hopefully this week, if she's not bred back....she looks a little fluffy but she always looks that way in the winter time. Could be she's preggers again, so we'll have to see what comes out this time. THEN we'll get her fixed as quickly as possible.
I can't stop admiring him, as he's just that beautiful....that color and fur texture is much like a Rex rabbit. Just luxurious to see and touch.