CONTEXT: The incidence of recurrent miscarriage (RM) (>or=3 consecutive pregnancy losses) is estimated as 1-2% in fertile couples. Familial clustering of RM has suggested the contribution of a genetic component. OBJECTIVE: A low level of human chorionic gonadotropin (HCG) in maternal serum during the first trimester of the pregnancy is a clinically accepted risk factor for miscarriage. We sought to study whether variation in chorionic gonadotropin beta-subunit genes (CGBs) expressed in placenta may contribute to the risk of RM. DESIGN: Resequencing of CGB5 and CGB8, the two most actively transcribed loci of the four HCG beta-duplicate genes, was performed. SETTING: A case-control study involving two sample sets, from Estonia (n = 194) and Finland (n = 185), was performed. PATIENTS: RM patients (n = 184) and fertile controls (n = 195) participated in the study. RESULTS: From 71 identified variants in CGB5 and CGB8, 48 polymorphisms were novel. Significant protective effect was associated with two single nucleotide polymorphisms located at identical positions in intron 2 in both CGB5 [P = 0.007; odds ratio (OR) = 0.53] and CGB8 (P = 0.042; OR = 0.15), and with four CGB5 promoter variants (P < 0.03; OR = 0.54-0.58). The carriers of minor alleles had a reduced risk of RM. The haplotype structure of the CGB8 promoter was consistent with balancing selection; a rare mutation in CGB8 initiator element was detected only among patients (n = 3). In addition, three rare nonsynonymous substitutions were identified among RM cases as possible variants increasing the risk of recurrent pregnancy loss. CONCLUSION: The findings encourage studying the functional effect of the identified variants on CGB expression and HCG hormone activity to elucidate further the role of CGB variation in RM.
CONTEXT: The incidence of recurrent miscarriage (RM) (>or=3 consecutive pregnancy losses) is estimated as 1-2% in fertile couples. Familial clustering of RM has suggested the contribution of a genetic component. OBJECTIVE: A low level of human chorionic gonadotropin (HCG) in maternal serum during the first trimester of the pregnancy is a clinically accepted risk factor for miscarriage. We sought to study whether variation in chorionic gonadotropin beta-subunit genes (CGBs) expressed in placenta may contribute to the risk of RM. DESIGN: Resequencing of CGB5 and CGB8, the two most actively transcribed loci of the four HCG beta-duplicate genes, was performed. SETTING: A case-control study involving two sample sets, from Estonia (n = 194) and Finland (n = 185), was performed. PATIENTS: RM patients (n = 184) and fertile controls (n = 195) participated in the study. RESULTS: From 71 identified variants in CGB5 and CGB8, 48 polymorphisms were novel. Significant protective effect was associated with two single nucleotide polymorphisms located at identical positions in intron 2 in both CGB5 [P = 0.007; odds ratio (OR) = 0.53] and CGB8 (P = 0.042; OR = 0.15), and with four CGB5 promoter variants (P < 0.03; OR = 0.54-0.58). The carriers of minor alleles had a reduced risk of RM. The haplotype structure of the CGB8 promoter was consistent with balancing selection; a rare mutation in CGB8 initiator element was detected only among patients (n = 3). In addition, three rare nonsynonymous substitutions were identified among RM cases as possible variants increasing the risk of recurrent pregnancy loss. CONCLUSION: The findings encourage studying the functional effect of the identified variants on CGB expression and HCG hormone activity to elucidate further the role of CGB variation in RM.
Authors: David Fredman; Stefan J White; Susanna Potter; Evan E Eichler; Johan T Den Dunnen; Anthony J Brookes Journal: Nat Genet Date: 2004-07-11 Impact factor: 38.330
Authors: Liina Nagirnaja; Česlovas Venclovas; Kristiina Rull; Kim C Jonas; Hellevi Peltoketo; Ole B Christiansen; Visvaldas Kairys; Gaily Kivi; Rudi Steffensen; Ilpo T Huhtaniemi; Maris Laan Journal: Mol Hum Reprod Date: 2012-05-03 Impact factor: 4.025
Authors: Liina Nagirnaja; Diana Nõmmemees; Kristiina Rull; Ole B Christiansen; Henriette S Nielsen; Maris Laan Journal: PLoS One Date: 2015-07-02 Impact factor: 3.240
Authors: Kristiina Rull; Ole Bjarne Christiansen; Liina Nagirnaja; Rudi Steffensen; Tõnu Margus; Maris Laan Journal: Fertil Steril Date: 2013-03-15 Impact factor: 7.329