Austria, too, has a growing reputation for sweet wine, with producers such as Nittnaus, Hiedler, Tinhof and Willi Opitz.

WSJ: Will Lyons on Wine: Something Sweet for Your Sweet

The discovery that both boys had a rare metabolic condition called Smith-Lemli-Opitz syndrome (SLOS), which results from a failure of the body to make its own cholesterol, explained many of their struggles during their early years.

BBC: 'No-one had heard of my boys' syndrome'

At Cardiff University Dr Emyr Lloyd-Evans has been given funding by children's charity Action Medical Research to unlock the secrets of Smith-Lemli-Opitz syndrome by investigating the processes that cause it and analysing two possible new treatments and how they might work.

BBC: 'No-one had heard of my boys' syndrome'