Table 1.

Characteristics of monozygotic and dizygotic twin siblings of patients with type 1 diabetes

Detail	Monozygotic twins (n=53)	Dizygotic twins (n=30)
Recruited at BDC:Joslin Clinic	17:36	20:10
Sex distribution (index/non-index)	26 M/M, 27 F/F	5 M/M, 9 F/F, 6 M/F, 10 F/M
Median (range) discordance:
At first visit	1.9 (0-28.2)	1.9 (0-14.8)
At last antibody test	7.6 (0-44.7)	2.5 (0-14.8)
Median (range) age (years):
At first visit	13.6 (2.1-52.7)	10.1 (1.8-33.2)
At last antibody test	21.5 (3-64.4)	10.5 (2.4-34.2)
Non-index twins tested for ICA*	53	30
Non-index twins tested for “biochemical” autoantibodies†:
No antibody	1	2
One autoantibody	10	5
Two autoantibodies	4	0
Three autoantibodies	38	23

^*Cytoplasmic islet cell autoantibodies. 

^†Insulin, GAD65, and ICA512 autoantibodies.