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START: Susceptibility to Food Allergies in a Registry of Twins
Sunday, March 6, 2016
South Exhibit Hall H (Convention Center)
Sarah De Schryver, MD, Alizee Dery, Ann Elaine Clarke, MD, MSc, Kari C. Nadeau, MD PhD FAAAAI, Laurie Harada, BA, Celia Greenwood, Kimberley Weatherall, Denise Daley, Yuka Asai, MD, Fiona Bamforth, Moshe Ben-Shoshan, MD, MSc
Rationale:

To compare proband-concordance [(twice number concordant pairs)/(twice number of concordant pairs+ number of non-concordant pairs)] in MZ (monozygotic) and DZ (dyzgotic) twins with food allergy.

Methods:

Twins, with at least one member with peanut or tree-nut allergy, were recruited from Anaphylaxis Canada, Multiple-Births-Canada, a US registry and the Montreal Children’s Hospital allergy clinics. Diagnosis of food allergy was based on a convincing clinical history AND a skin prick test or allergen-specific IgE level beyond previously published thresholds or a positive food challenge.

Results:

Among 10 pairs of MZ and 13 pairs of DZ twins with peanut allergy, the concordance-rate was 0.67 (95%CI, 0.39, 0.87) and 0.82 (95%CI, 0.59, 0.94) respectively [difference=0.15 (95%CI, -0.19, 0.5)]. Among 9 pairs of MZ and 4 pairs of DZ twins with cashew/pistachio allergy, the concordance-rate was 0.40 (0.18, 0.67) and 0.40 (0.14, 0.73) respectively [difference=0.0 (-0.39, 0.39)]. Among 7 pairs of MZ and 3 pairs of DZ twins with pecan/walnut allergy, the concordance-rate was 0.6 (0.27, 0.86) and 0.50 (0.15, 0.85) respectively [difference=-0.10 (-0.78, 0.58)]. Among 6 pairs of MZ and 2 pairs of DZ twins with hazelnut allergy the concordance-rate was 0.29 (0.51, 0.70) and 0.67(0.13, 0.99) respectively [difference=0.38 (-0.49, 1.00)].Among 2 pairs of MZ and 1 pair of DZ twins with almond allergy the concordance-rate was 0.00 (0.00, 0.80) and 1.00(0.20, 1.00) respectively [difference=1.00 (0.50, 1.00)].

Conclusions:

It is likely that non-genetic factors play a major role in the development of food allergy. However, our small sample size precludes definitive conclusions.