Celiac.com 05/02/2002 – Results of the first large population-based twin study of celiac disease were recently published in the April edition of the journal Gut. The study was conducted by Professor L Greco and colleagues at the UniversitÃ di Napoli Federico II, Dipartimento di Pediatria. The study compared identical twins (genetically identical) to fraternal twins (genetically not identical) who share only the same number of genes as non-twin siblings. This methodology allowed the researchers to determine what role a shared environment plays in the onset of celiac disease in comparison to a genetic role.
The researchers matched the Italian Twin Registry with the membership lists of a patient support group for celiacs. Forty seven twin pairs were found and screened for antiendomysial (EMA) and antihuman-tissue transglutaminase (anti-tTG) antibodies. Identical twins were verified using DNA fingerprinting and fraternal twins were typed for HLA class II DRB1 and DQB1 molecules.
Their results indicate that 38% of the combined twin pairs showed signs of celiac disease, which breaks down to 75% of the identical twin pairs and 11% of the non-identical twin pairs. Additionally, females who had a twin with celiac disease were 30% more likely to develop it themselves, in comparison to an unaffected male twin. Further, the results of the study indicate that environmental factors have little or no effect on the acquisition of celiac disease, and that there is substantial evidence of a very strong genetic component that is only partially related to the HLA region. The researchers suggest that several genes work collectively to cause celiac disease, and a single missing or altered gene is probably not its cause.