All the Saints who have gone before us- indeed, all who have fallen asleep in Christ- live to God.
And we may ask for their intercessions concerning any malady and any matter. But in some places, chiefly the west, certain Saints are counted as special intercessors for certain specific things.
In relation to persons with disabilities, Saint George is counted as an intercessor for persons with leprosy and skin diseases.
Here is a good account of his life from an Orthodox Christian Parish for which he is the patron Saint, St. George Orthodox Cathedral in Wichita, Kansas: http://www.stgeorgecathedral.net/saints_george.html
A Roman Catholic source: http://saints.sqpn.com/saint-george/