- Scleroderma defined as systemic sclerosis with diffuse or limited scleroderma meeting the American College of Rheumatology (ACR) criteria (33). Cases will be included if they meet clinical features that satisfy ACR criteria for a diagnosis of scleroderma or the presence of three of five features of the CREST syndrome are identified; or there is the presence of definite Raynaud's phenomenon, abnormal nail fold capillaries typical of scleroderma and the presence of a specific scleroderma related auto-antibody. Limited skin involvement is defined as skin tightening distal to elbows and knees with or without facial involvement; and diffuse skin involvement, tightening proximal to these joints or truncal involvement.