Demi-Leigh Mahon told she wouldn't live past age two defies the odds Demi-Leigh Mahon has a condition so rare that doctors named it after her Her lungs and heart failed to develop properly in the womb she is susceptible to infection, meaning a simple cold can be life-threatening Doctors warned her parents she wouldn't live past her second birthday Instead of 16th birthday presents, she asked friends to donate to charity A girl who wasn't expected to live past the age of two has defied the odds to celebrate her 16th birthday. Demi-Leigh Mahon was born with a condition which is so rare that doctors named it after her. It left her incredibly susceptible to infection after her lungs and heart failed to develop properly in the womb. Celebrating: Demi-Leigh Mahon was not expected to live more than two years after she was born with a rare medical condition Survivor: Demi-Leigh (pictured aged two) was born with a condition which left her incredibly susceptible to infection after her lungs and heart failed to develop properly in the womb Baffled doctors had never seen the condition before and warned her parents Kerry and Darren she was unlikely to see her second birthday. But the teenager - who is often so sapped of energy she needs to sleep for four days just to regain the strength to walk - turned 16 on Tuesday. As a result of her condition, Demi-Leigh, from Telford, Shropshire, suffers shortness of breath, chronic bronchiectasis (a disease of the lungs) and has a defective heart valve. Her tiny body is also unable to produce vital B-cells that fight infections and three years ago she underwent a lens transplant to remove cataracts in her eyes. Demi-Leigh, who is waiting for a double lung transplant, said: 'Iâ€™m so happy to be 16. I havenâ€™t had the easiest time but with the help of my family and friends Iâ€™m determined to get on with life. I love seeing my friends and my birthday was brilliant. I just try to take life one day at a time and deal with it as it comes. You have down days and up days, but the down days are a few more at the moment as I wait for the lung transplant. Caring: Demi-Leigh with her mother Kerry. As a result of her condition, the teenager also suffers shortness of breath, chronic bronchiectasis (a disease of the lungs) and has a defective heart valve There are worse off people than me though, so I just want to help the make-a-wish foundation help other people. I enjoyed my party, although I couldnâ€™t spend a lot of time with my friends as it was very tiring everyone was lovely. Her mother Kerry was forced to give her up her job as a machine operator to care full time for her daughter when she was a baby. When Demi-Leigh was 18 months old, she rushed her to hospital after she struggled to breathe. Concerned doctors diagnosed her with chronic pneumonia and warned Demi-Leigh was unlikely to survive the night. Mrs Mahon, who has another son Darrell, 19, said: 'It was so frustrating, I knew something was wrong with my daughter but no-one would listen to me. Defiant: Despite doctors' expectations, DEmi-Leigh, who is waiting for a double lung transplant, turned 16 this week 'I stood in the hospital after they told me to 'listen to my doctor and just give her Calpol' and said to the nurse that if I didnâ€™t get a second opinion I would stand there and scream. A young doctor said he would have a look and shortly after he sounded an alarm and she was rushed into surgery. They told me she had bad pneumonia and needed emergency surgery within minutes or she would die. Ever since she has been in and out of hospital every few months. 'It's amazing we've made every Christmas and birthday because her immune system means the slightest cold or chest infection is life threatening. What she goes through day to day is unimaginable. She has three nebulisers, intravenous antibiotics and an implant in her chest so she can have medication through that. Thoughtful: Rather than asking for birthday presents, Demi-Leigh asked friends to donate to the make-a-wish foundation, the charity which sent her to swim with dolphins in 2010 In one week, she has been to Great Ormond Street, a hospital in Leicester, on in Birmingham and back to Telford hospital. But she takes it all in her stride. Sheâ€™s an extraordinary girl. Everyone who meets her falls in love with her. Demi-Leighâ€™s father Darren, 36, a construction worker, added: 'She canâ€™t go to school at the moment, and can sleep for up to four days at a time. But she got herself up and ready to go in the limo for her 16th birthday. All the children from her school turned up and she had a fantastic time. She asked that no one giver her presents and they all give to the Make-a-Wish foundation, who sent her to swim with dolphins in 2010.