Progeria, also called Hutchinson-Gilford Progeria Syndrome, is a rare premature aging disease. Although born normal, children with Progeria rapidly lose hair, develop thin skin, loose subcutaneous fat, get stiff joints, and usually die of heart disease. The average life span is 13 years. Progeria has been termed "premature aging" syndrome because affected individuals look elderly as children. About 90% of cases are due to new mutations in the LMNA gene which is involved in cellular structure. How changes in this gene result in the distinctive features of progeria is unknown.