Archie Thompson is a child in a million - and not just in the eyes of his parents.

The two-year-old is one of just four children in the world with the rare genetic disease Momo, or macrosomia obesity macrophaly ocular abnormality syndrome.

It means the youngster already weighs more than 6st and is growing all the time.

The obesity caused by his illness has given Archie severe breathing and heart problems. It has also resulted in poor eyesight and learning difficulties.

As his weight increases by 1lb a week, Archie's family are determined to give him the best possible life they can.

His mother Sarah, 34, said: "He has dealt with this so well. Obviously he has never known any different but the way he copes has been tremendous.

"If you or I had to stay in a chair all the time it would drive us mad but he simply accepts it all."

Archie, from Icklesham, near Rye, was born weighing a healthy 8lb 4oz, only slightly heavier than his two older sisters.

But, as the youngster's condition deteriorated and doctors desperately tried to discover what was wrong with him, Sarah and Archie's father, Nigel, realised things were serious.

Doctors cannot tell them how long Archie will live. He is at home rather than in hospital to reduce the risk of picking up infections and needs 24-hour care.

He has to be propped up to sleep under sedation and often needs to be moved to stop him getting cramp.

Sarah is hoping this year Archie will be well enough to start at Glyne Gap, Bexhill, a school for children with severe learning difficulties, where he will receive physiotherapy, hydrotherapy and sensory stimulation.

Sarah said: "I just want Archie and my family to be happy. We are just a small family with a special little boy."