Population based study of prevalence of islet cell autoantibodies in monozygotic and dizygotic Danish twin pairs with insulin dependent diabetes mellitus.
OBJECTIVE
To study the comparative importance of environment and genes in the development of islet cell autoimmunity associated with insulin dependent diabetes mellitus.


METHODS
Population based study of diabetic twins.


METHODS
Danish population.


METHODS
18 monozygotic and 36 dizygotic twin pairs with one or both partners having insulin dependent diabetes.


METHODS
Presence of islet cell antibodies, insulin autoantibodies, and autoantibodies to glutamic acid decarboxylase (GAD65) in serum samples from twin pairs 10 years (range 0-30 years) and 9.5 years (2-30 years) after onset of disease.


RESULTS
In those with diabetes the prevalence of islet cell antibodies, insulin autoantibodies, and autoantibodies to glutamic acid decarboxylase in the 26 monozygotic twins was 38%, 85%, and 92%, respectively, and in the dizygotic twins was 57%, 70%, and 57%, respectively. In those without diabetes the proportions were 20%, 50%, and 40% in the 10 monozygotic twins and 26%, 49%, and 40% in the 35 dizygotic twins.


CONCLUSIONS
There is no difference between the prevalence of islet cell autoantibodies in dizygotic and monozygotic twins without diabetes, suggesting that islet cell autoimmunity is environmentally rather than genetically determined. Furthermore, the prevalence of islet cell antibodies was higher in the non-diabetic twins than in other first degree relatives of patients with insulin dependent diabetes. This implies that the prenatal or early postnatal period during which twins are exposed to the same environment, in contrast with that experienced by first degree relatives, is of aetiological importance.
Petersen
J S
JS
Hagedorn Research Institute, Gentofte, Denmark.
Kyvik
K O
KO
Bingley
P J
PJ
Gale
E A
EA
Green
A
A
Dyrberg
T
T
Beck-Nielsen
H
H
D000293:Adolescent; D000328:Adult; D001323:Autoantibodies / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003718:Denmark; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology*; D004200:Diseases in Twins; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007330:Insulin Antibodies / Q000032:analysis; D007515:Islets of Langerhans / Q000276:immunology*; D008297:Male; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic
D001323:Autoantibodies; D007330:Insulin Antibodies; D005968:Glutamate Decarboxylase