Example of Twin Study

Mack and colleagues* ascertained the concordance of Hodgkin’s disease in twins over a period of years after the diagnosis of the cancer had been made in the first twin. Their aim was to see if the frequency of the cancer in the second twin differed between monozygotic and dizygotic twins. They found that ten of the 179 monozygotic twins went on to develop cancer but none of the 197 dyzygotic twins developed the condition. The greater concordance between the monozygotic twins, compared to the dyzygotic twins, suggests that genetic factors do play a role in the development of this type of cancer.

*Mack TM, Cozen W, Shibata DK, Weiss LM, Nathwani BN, Hernandez AM, Taylor CR, Hamilton AS, Deapen DM, Rappaport EB. Concordance for Hodgkin's disease in identical twins suggesting genetic susceptibility to the young-adult form of the disease. N Engl J Med. 1995 Feb 16;332(7):413-8. http://www.ncbi.nlm.nih.gov/pubmed/7824015

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