The extremely rare condition causes accelerated ageing, fat loss from the face and body, along with tissue degeneration.
Regardless of her size, this is one very strong lady - her constant struggle has been described as a 'living nightmare'.
Hailing from Austin, Texas, Ms Velasquez (who wears triple zero size clothes) has said, "I weigh myself regularly and if I gain even one pound I get really excited... I eat every 15-20 minutes to keep my energy levels up... I eat small portions of crisps, sweets, chocolate, pizza, chicken, cake, doughnuts, ice cream, noodles and pop tarts all day long, so I get pretty upset when people accuse me of being anorexic".
A book about Ms Velasquez's condition and her courageous battle, is due in bookstores this September.