Child in a million. Part 3, Kyle and Leanne.

The third in a six-part series following the stories of children undergoing pioneering treatments for rare medical conditions at London's Great Ormond Street Hospital. This part tells the moving stories of Kyle and Leanne. Seven-year-old Kyle has an extremely rare immune deficiency condition, CD40, and needs to undergo a bone marrow transplant which in itself may kill him - surgeon Paul Veys describes the risks and we see quite detailed footage of the surgery itself. Sixteen-year-old Leanne has pulmonary hypertension which leaves her at risk of death at any moment, only two people in a million suffer from this condition so her diagnosis took a long time to make. There is no cure but there is a very complex drug regime which Leanne has learnt to administer to herself at home. Eventually she could consider a lung transplant although that is a very risky procedure.