BACKGROUND: Sex differences in structural birth defects are often confounded by environmental risk factors. Opposite-sex twins provide a unique model for detecting sex differences in birth defects while maximally controlling environmental risk factors in a natural setting. METHODS: Population data from the Florida Birth Defects Registry were analyzed. A total of 4,768 pairs of twins who were discordant for sex and born between 1996 and 2001 were analyzed. The McNemar test was used to compare the differences between a male twin and his twin sister for the risk of developing specific defects and organ-system defects. RESULTS: Of 4,768 twin pairs, 225 males (4.72%) and 175 females (3.67%) had birth defects. Among opposite-sex twin pairs, males had a 29% higher risk for birth defects than their twin sisters. Compared to their twin sisters, males had a 5.4 times higher risk for pyloric stenosis and a 2.4 times higher risk for obstructive genitourinary defect, but only one-tenth the risk for congenital hip dislocation. CONCLUSIONS: Sex differences in birth defects exist between opposite-sex twins.
BACKGROUND: Sex differences in structural birth defects are often confounded by environmental risk factors. Opposite-sex twins provide a unique model for detecting sex differences in birth defects while maximally controlling environmental risk factors in a natural setting. METHODS: Population data from the Florida Birth Defects Registry were analyzed. A total of 4,768 pairs of twins who were discordant for sex and born between 1996 and 2001 were analyzed. The McNemar test was used to compare the differences between a male twin and his twin sister for the risk of developing specific defects and organ-system defects. RESULTS: Of 4,768 twin pairs, 225 males (4.72%) and 175 females (3.67%) had birth defects. Among opposite-sex twin pairs, males had a 29% higher risk for birth defects than their twin sisters. Compared to their twin sisters, males had a 5.4 times higher risk for pyloric stenosis and a 2.4 times higher risk for obstructive genitourinary defect, but only one-tenth the risk for congenital hip dislocation. CONCLUSIONS: Sex differences in birth defects exist between opposite-sex twins.
Authors: Kate V Everett; Barry A Chioza; Christina Georgoula; Ashley Reece; Francesca Capon; Keith A Parker; Cathy Cord-Udy; Paul McKeigue; Sally Mitton; Agostino Pierro; Prem Puri; Hannah M Mitchison; Eddie M K Chung; R Mark Gardiner Journal: Am J Hum Genet Date: 2008-02-28 Impact factor: 11.025
Authors: Jiude Mao; Xia Zhang; Paizlee T Sieli; Michael T Falduto; Karen E Torres; Cheryl S Rosenfeld Journal: Proc Natl Acad Sci U S A Date: 2010-03-08 Impact factor: 11.205
Authors: Silvija Cvitic; Mark S Longtine; Hubert Hackl; Karin Wagner; Michael D Nelson; Gernot Desoye; Ursula Hiden Journal: PLoS One Date: 2013-10-29 Impact factor: 3.240