They revealed his seventh chromosome had an 'extra arm' which has never been documented anywhere in the world before.
Doctors are baffled at his condition, which is so rare it does not have a name.
His condition left Alfie unable to see until he was three months old and his muscles were so weak he could not roll over on his own.
He still suffers serious digestive problems and needs a cocktail of drugs every day to help his body absorb vital nutrients.
He also suffers fits which sparked by high temperatures and metabolic problems stop him from eating or drinking.
Since he was born, Alfie has been rushed to hospital six times - including twice just last month - when he stopped breathing.
His parents even believed he was dying twice and were stunned when Alfie made a full recovery after spending time in hospital.
Mr and Mrs Clamp, who also have 10-year-old daughter Georgia who is perfectly healthy, had their DNA tested but were not carriers of the faulty gene.
Mr Clamp said: 'The doctors told us there is nothing we could have done to prevent it. I don't think we'll ever know why it happened.
'I was holding him in my arms and I could see his eyes start to focus on me. It was a massive milestone for us because we didn't know if that would ever happen.
Read more: http://www.dailymail.co.uk/health/articl...d-DNA.html
This is technically not an entirely human child is it...