I have never seen something like this: 130 cats, almost all ginger and ginger-and-white, all siblings from one mother who was rescued when pregnant by a woman living in Moscow, Russia. And they were living in a one bedroomed apartment.

Two useful tags. Click either to see the articles: Toxic to cats | Dangers to cats
All the cats are siblings. It took four years to get to this state. She never sterilised anyone of them. They interbred, sibling-to-sibling and I suppose male sibling-to-mother.
Astonishingly, none of the cats had an infection. All were clean and affectionate. An odour from the flat alerted neighbours and the woman eventually agreed to accept help. Volunteers from a charity, Zoo Defenders, including Irina Medvedeva and Anastasia Soloviyeva took away 50 and 80 remain for the time being.
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Useful tag. Click to see the articles: Cat behavior
Wow, just wow. What else can one say? No problems from inbreeding either? It’s still wrong to allow this to happen but amazing. Glad she finally accepted help, but man did she let it go too far.
It looks bizarre but I guess it was predictable. I am very surprised she allowed it to happen.