If the mama cat had feline lukemia, does that mean her kittens have it too?

A man in my apartment complex knew I was an animal lover so when he got kicked out of his apt he left his three cats on my doorstep. One of them, Molly, happened to be pregnant. The vet seems to think she has feline lukemia. About 10 months after having her kittens Molly disappeared. I found homes for her kittens but kept one named Trudy. She is a little over a year, and is extremely small. She probably weighs like 2 pounds. She eats alot though. Her mom was really small too though. Trudy gets spayed next week and I am wondering if it will fatten her up.... and If her mom had feline lukemia does that mean she does too?