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.
Jury told to consider ‘different strands’ of evidence in Natalie McNally murder case
Civil case taken by IRA victims ‘verged on show trial’, Gerry Adams says
High Court told Gerry Adams ‘major, major player in war!'
Natalie McNally murder accused ‘lied and lied again’
Woman dies in two-vehicle collision in Enniskillen