...results from MRI scan show no further abnormalities on brain other than the enlarged ventricles.
While that doesn't mean that the brain will actually be working as it should, it is "encouraging", as the consultant put it to me today.
He's also discussed my case with a genetics team, but they haven't got anything to add at this stage - which I suppose is also good in a way, as it can't be any obvious genetic disorder then.
So I'm feeling a glimmer of hope, albeit a tiny one.