Why was a genetic diagnosis so important?

He wasn’t developing as my other child had. By a year old I was getting very, very concerned. They kept saying ‘He’s been very sick, he’ll catch up’ and then at 18 months I said ‘No, this isn’t right, there’s something wrong with him’. He didn’t start walking until he was over 2 and that was after intensive physio. Emma (Jack’s Mum)

Genetic testing identified a base substitution in the KCNJ11 gene that is the cause of Jack’s neonatal diabetes. This change affects just one of the 3,000,000,000 bases of his DNA. The specific genetic change that Jack has (p.Val59Met or abbreviated to V59M) is the cause of his learning difficulties and muscle weakness; we will explain more about this in step 1.7. Identifying the genetic change provides an explanation for both Jack’s diabetes and his developmental delay.