THE youngest of four Romsey brothers all diagnosed with a fatal genetic condition is preparing for a bone marrow transplant.

Six-year-old Luke Hartley will have the transplant at Great Ormond Street Hospital at the end of January, coinciding with his seventh birthday, which falls on the 25th.

He will then have to spend up to three months in hospital recovering. Luke's three older brothers - Joshua, 14, Nathan, 12, and Daniel, 10 - have all already undergone successful bone marrow transplants.

The boys all have the rare X-linked Lymphoproliferative Syndrome, also known as Duncan's Disease, which leaves them with no immunity to illnesses such as severe glandular fever and cancer of the blood.

A bone marrow transplant is the only permanent solution, giving them new immune systems.

Dad David Hartley said Luke is positive about his stay in hospital. He said: "In a strange way, because it's not an invasive procedure and they look after children so well at Great Ormond Street, Luke is not afraid. He has seen his brothers go through it and has seen them come back with no hair, which he found very funny - he is looking forward to losing his hair. He is a very brave young man for his age.

"If you met him, you wouldn't think there was anything wrong, but he has a ticking time bomb in him and the younger he is the better to have this transplant."

David, who runs a software company, added: "We have been through it three times and there have been real highs but also incredible lows. We know it's going to be a rough time as it's a very serious procedure.

"We just want to get Christmas and New Year out the way and then concentrate on making certain he is well and, hopefully, can be back home in time for Easter. We are resigned to the fact he has got to have it, but it's not easy to go through."

Luke went up to Great Ormond Street Hospital on Sunday to have a feeding tube inserted into his stomach in preparation for the transplant. He was due to return home today.

The XLP charity, launched by David and Allison Hartley, to fund research into the condition is continuing its fundraising. Visit www. xlpresearchtrust.org