Dad Ian Legg, co-founder of the Noonan Syndrome Association, says his son lived a fulfilling life. "What he achieved in 33 years, most of us never achieve in 70," he said.

Researchers from Loughborough University spoke to 67 families living with Noonan syndrome. The genetic condition affects between one in 2,000 and one in 2,500 UK births, says the NHS.