What medical problem did gary coleman have/die from?

His short stature (4 feet, 8 inches or 1.42 meters) stemmed from congenital autoimmune kidney disease and its treatment. He underwent at least two kidney transplants early in his life, and required frequent dialysis, which he preferred not to discuss. In 2009, he underwent heart surgery, details of which were never made public, but he was known to have developed pneumonia postoperatively. In January 2010 he was hospitalized after a seizure in Los Angeles, and in February he suffered another seizure on the set of The Insider television program and died.