Study on the Imprinting Status of Insulin‐Like Growth Factor II (IGF‐II) Gene in Villus during 6–10 Gestational Weeks

Abstract

Objective . To compare the difference of imprinting status of insulin‐like growth factor II (IGF‐II) gene in villus between normal embryo development group and abnormal embryo development group and to investigate the relationship between karyotype and the imprinting status of IGF‐II gene. Methods . A total of 85 pregnant women with singleton pregnancy were divided into two groups: one with abnormal embryo development ( n = 38) and the other with normal embryo development ( n = 47). Apa I polymorphism of IGF‐II gene in chorionic villus was assayed with reverse transcriptase polymerase chain reaction (RT‐PCR) and restriction fragment length polymorphism (RFLP). The relationship between chromosomal abnormal karyotype and IGF‐II gene imprinting status was analyzed by primary cell culture and G‐banding chromosomal karyotype analysis. Results . IGF‐II imprinting loss rate was higher in the abnormal embryo development group than the normal embryo development group (44.7% versus 31.6%), but without significant difference ( P > .05). The percentage of abnormal chromosomes of chorionic villus in the abnormal embryo development group was 42.5%, in which IGF‐II imprinting loss rate reached 64.7%. No abnormal karyotypes were found in the normal embryo development group. However, there was significant difference in IGF‐II imprinting loss rate between two groups ( P > .05). Conclusion . During weeks 6–10 of gestation, abnormal embryonic development is correlated with chromosomal abnormalities. The imprinting status of IGF‐II gene played important roles in embryonic development, and imprinting loss might be related to chromosomal abnormalities.