Celiac.com 04/09/2008 - Do your chances of developing celiac disease vary depending on which parent is passing on the genes? A new study says yes.
An Italian research team set out to examine risk differences for developing celiac disease between males and females. The research team was made up of Francesca Megiorni, B.Sc., Barbara Mora, B.Sc., Margherita Bonamico, M.D., Maria Barbato, M.D., Monica Montuori, M.D., Franca Viola, M.D., Simonetta Trabace, B.Sc., and Maria C. Mazzilli, B.Sc.
HLA typing in celiac disease is mainly considered for its negative predictive value, as people who do not carry the DQ predisposing molecules are unlikely to develop the disease. Celiac disease occurs twice as often in women as it does in men. In order to learn more about why this might be, the team of researchers recently performed genotyping for HLA-DRB1, DQA1, and DQB1 loci on 281 female and 156 male pediatric celiac patients, 292 nuclear families, and 551 controls. The team then evaluated and compared the odds ratio, parental origin of the disease-associated haplotypes, and transmission ratio distortion between male and female patients.
Female patients more frequently exhibited DQ2/DQ8 compared to male patients (94% F, 85% M; P = 1.6 Å~ 10âˆ’3). The HLA typing test carried a calculated negative predictive value of 99.1% for females and 90.5% for men. Interestingly, the bulk of the 39 DQ2/DQ8 negative cases were male. Looking at the origins of the DQ2 haplotype, the research team noted that 61% of female patients and 42% of male patients carried a paternal combination (P = 0.02).
Looking at the results of the transmission disequilibrium test (TDT) the team noted a major distortion in the DR3-DQ2 transmission from fathers to daughters. Among those patients that are DQ2/DQ8 positive, females showed a higher prevalence of celiac disease than did male patients, with a ratio of 1.8 to 1. Of those patients that were DQ2/DQ8 negative there was a slight tip toward the males, with a ratio of .7 to 1.
The high prevalence of celiac disease in DQ2/DQ8 positive females only applied to females that had inherited the DQ2 haplotype from the father. The results of the study indicate that the sex of the parent supplying the HLA genes may play a role in susceptibility to celiac disease, along with a different effect of parent-specific epigenetic modifications in the two genders.
In all, male patients developed celiac disease more frequently than female patients in absence of HLA predisposing dimmers, but this was due to the occurrence of two DQB1 susceptible alleles that seem to increase the disease risk for males. The results lead the research team to believe that the presence of DQ2 and/or DQ8 molecules is a stronger risk factor in females than in males (ORF = 40.5, ORM = 14.1). Additionally, the results also indicate that HLA typing, which is mainly considered for its negative predictive value in celiac disease, is of greater importance in the testing of females than in males, with calculated negative predictive value of 99.1% and 90.5%, respectively, which points to the need to factor gender into the calculation of disease risk.
These findings, taken together with the revelation that inheritance of a paternal DQ2 haplotype led to celiac predominance in daughters, show that HLA genes play a role in the disease sex bias, and imply a potentially different effect of parent-speciï¬c epigenetic modiï¬cations in the two genders.
Am J Gastroenterol 2007; 102:1–7