Type-Specific Concordance in Young Diabetic Monozygotic Twins
In 1972, Tattersall and Pyke (1) indicated that the level of concordance for diabetes among monozygotic twins depended upon the age of onset of diabetes in the index twin. If diabetes developed before 40 years of age, the subsequent concordance was estimated at 53%; it increased to 92% when the index twin was older than 40 years at diagnosis. It has been realized subsequently that classification of diabetic patients into Type I (insulin dependent) and 2 (non-insulin dependent) on the basis of age alone is in-sufficient (2), Epidemiologic observations in Olmsted County, Minnesota have revealed that while all cases with the onset of diabetes in the first decade of life were insulin dependent, those who became diabetic in the second and third decade included 37% and 50% respectively, who actually were non-insulin dependent cases (3). In a population study from East Finland, Laakso and Pyorala (4) also found heterogeneity of the type of diabetes among young patients. Approximately 7% and 20% of those cases with the onset of diabetes in the third and fourth decade were non-insulin dependent. It is conceivable that the monozygotic twins with onset of diabetes before 40 years of age described by Tattersall and Pyke (1) were also a mixed group.
KeywordsGestational Diabetes Twin Pair Early Treatment Diabetic Retinopathy Study Olmsted County Body Mass Index
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