Table I.

Pairwise concordance rates of autoimmune disease in monozygotic and dizygotic twins (n of concordant sets/n of studied sets)

Disease	MZ concordance rate	DZ concordance rate
Primary biliary cirrhosis	0.63	0.00
Primary sclerosing cholangitis	Concordant pair reported	–
Systemic lupus erithematosus	0.24	0.02
Sjögren’s syndrome	Concordant pair reported	–
Type I diabetes mellitus	0.21-0.70*	0.00-0.13
Rheumatoid arthritis	12.3-15.4	3.50-3.60
Graves’ disease	0.17-0.29	0.00-0.02
Multiple sclerosis	0.25-0.31*	0.03-4.7
Celiac disease	0.75-0.83	0.11

^* Following a minimum of 7.5 years of observation