They say good things come in small packages, and little Eva Pym is proof of that. She may be tiny, but this precious little girl is proving to be a big-hearted fighter and an endless source of joy and inspiration to her loving mum and dad, Katherine and Daniel.

Eva was born full term weighing just 1.86kg (4.2lb). She came into the world with an extremely rare “genetic chromosome deletion” – which means her body is missing the vital “programming” it needs to know how to develop normally. Compared to other 18-month-olds, Eva, at 68cm, is tiny. Because of her condition, she may never grow taller and, as she gets older, the gap between her and other children of the same age will become even more pronounced. Her grandmother Noelene nicknamed her Thumbelina after the much-loved Hans Christian Andersen fairytale. Mum and Dad prefer to call her little Evie. “Basically, she’s the only one in the world with her condition,” says Katherine, 27. “We only found out in July that Eva’s specific gene deletion has never been detected in any DNA test in the world.

“Very little is known about the condition and there is very little information available, so Eva’s future is very uncertain. As parents, we are devastated that our daughter has to face the unknown, and that even doctors don’t know what to expect because they have never seen a case like it before.”

Watch a video of Eva playing with a normal sized 18-month-old baby in the player at the top of this page.

To read about the traumatic health issues that Eva has been plagued with since birth and how her parents are coping, get this week's Woman's Day, on sale January 9, 2012.