Dermot Devlin campaigned to get Vimizim approved in the UK after suffering from a rare degenerative disease.
The government legalised the drug on Monday and Dermot had his first treatment on Tuesday.
The birth defect, called Morquio, means his body is around 3 foot tall, which cramps the organs.
One major organ affected is the lungs - which resulted in Dermot collapsing on a plane.
He hopes this new treatment will give him back his independence.
Dermot has also called for the Irish government to follow in the UKs footstep.
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