The condition the three children were suffering from meant they were unable to talk or walk and were slowly dying.
It has been described as an incredibly debilitating disorder.
The four-year-old girl was diagnosed first followed by the younger twin boys.
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Police have released an e-fit of a man suspected of attacking her.
The force has been tweeting after carrying out a series of dawn raids.
Adenike Akingbogun made the dangerous manoeuvre after ignoring the crossing lights and driving onto the tracks.