Family-based Association Study Between MTNR Gene And PAI-1 Gene 4G/5G Polymorphisms And PCOS In Han Chinese

Part ⅠFamily-based genetic analysis of MTNR gene polymorphisms in Chinese polycystic ovary syndromeBackground:Polycystic ovary syndrome (PCOS) is a complex disease involving multiple organs, reproductive-endocrine and metabolic abnormalities disease. One of the main pathophysiology currently accepted was caused by insulin resistance and hyperinsulinemia, could lead to a serise of metabolic disorder and long-complications. This is similar to the pathophysiology of type 2 diabetes. Melatonin receptor gene was a new candidate gene for T2DM. Studies hve found that single nucleotide polymorphism (SNP) rs10830963 was associated with insulin secre, glucose tolerance and testosterone concentrations of PCOS women, but has no association with the susceptibility of PCOS. Our previous case-control study found that rs2119882 of the MTNR1A and the rs10830963 of the MTNR1B were associated with the disease susceptibility of PCOS. Inconsistent results may be affect -ed by different ethnic and environmental factors and population stratification and were limitated by the design of case-control study.Transmission disequilibrium test (TDT), a research method based on the nuclear family, was applied widely in recent years and became the main method used to study the complex genetic diseases. The TDT research can ensure the consistency of the genetic background between the case group and control group,and genetic mismatching by an appropriate"internal control"and was not influenced by genetic method, and population stratification, environmental factors or genetic heterogeneity.Objective:This study used family-based analysis of transmission disequilibrium test (TDT) to determine whether an association exists between two single nucleotide polymorphism (rs2119882 and rs10830963) of MTNR gene and PCOS women in Han Chinese.Methods:Seven hundred and eighty nine participants consisting of 263 trios (mother, father and offspring with PCOS) were recruited from the Center for Reproductive Medicine, Shandong University, from July 2007 to April 2014. Anthropometric variables such as height, weight, waist circumference(WC), hip circumference(HC), systolic blood pressure(SBP), diastolic blood pressure(DBP), and calculate the body mass index (BMI). Serum levels of fasting blood glucose (FBG) and fasting insulin (FINS), total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL) and high-density lipoprotein cholesterol (HDL) were measured and calculated the HOMA-IR. After 12hour empty-stomach in all subjects, Blood were withdrawed from these samples, the DNA was extracted for detecting genetic single nucleotide polymorphism. Six reproductive endocrine hormone and 75 grams of glucose tolerance test were measured for PCOS women additionaly. Women with PCOS were divided into two groups based on BMI:group A (BMI>25Kg/m2) and group B (BMI<25kg/m2). Parents of women with PCOS were accordingly categorized into group C and group D(fathers) and group E and group F(mothers). The two SNPs (rs2119882 and rs10830963)in the MTNR were genotyped using direct sequencing protocol and transmission disequilibrium test (TDT) was used to analyze the association between two SNPs of MTNR and PCOS.Results:Genotype distributions of the two SNPs were in Hardy-Weinberg equilibrium (P>0.05) in the families based analysis.After the TDT analyze,the C allele in SNP rs2119882 of the MTNR1A was overtransmitted in families(transmitted/non-transmitted==90:45; x2=5.33, P=0.0209). The C allele has statistical significance between obese and non-obese group of PCOS (x2=5.5983, P=0.018). While rs10830963 of MTNR1B has no statistical significance (transmitted/non-transmitted=76:51; x2=2.0, P=0.1573). We found that the Clinical and metabolic features were significant different between obese and lean PCOS and the parents. PCOS:FINS(mIU/1) (19.14±9.77,10.16±5.15, P<0.05); 2-h INS (mIU/1) (100.02±71.10,50.81±51.79, P<0.05);TG(mmol/1)(1.88±1.35,1.03±0.52, P<0.05); HOMA-IR(2.92±3.13,1.85±1.64, P<0.05); The fathers’s:FINS (mIU/1) (10.09±6.52, 5.08±2.18, P<0.05), HOMA-IR(0.95±1.82,0.39±0.68, P<0.05); The mathers’s HOMA-IR(0.96±1.69,0.54±0.99, P<0.05).The HOMA-IR has significant differenc in all three groups (P<0.05)Conclusion:The MTNR1B rs10830963 SNP has no association with PCOS. The SNP rs2119882 of MTNRIA was associated with PCOS and C allele may be the key to increase the risk of PCOS.Part ⅡFamily-based analysis of PAI-1 gene polymorphisms in Chinese polycystic ovary syndromeBackground:Insullin resistance (IR) is one of the mainly pathophysiology of PCOS. A large number studies have shown that 4G/5G polymorphism in promoter region of Plasminogen activator inhibitor-1 gene(PAI-1) can effect insullin sensitivity by elevating the level and activity of plasma PAI-1, involved in the formation of IR. The relationship between PAI-1 gene 4G/5G polymorphism and PCOS, several research conclusions are consistent. In order to make clear the relationship between PAI-1 gene 4G/5G polymorphism and PCOS, we used transmission disequilibrium test (TDT) to study the nuclear family of PCOS. TDT can guarantee the coherency of the all objects in same genetic background, eliminates the differences of traditional case-control study on genetic and environmental factors,and can eliminate the false positive results.Objective:This study used family-based analysis of transmission disequilibrium test(TDT) to determine whether an association exists between 4G/5G polymorphism of PAI-1 gene and PCOS and in Han Chinese in order to identify PAI-1 gene as a genetic susceptibility factor for PCOS.Methods:Eight hundred and fifty five participants consisting of 285 trios (mother, father and offspring with PCOS) were recruited from the Center for Reproductive Medicine, Shandong University, from July 2007 to eight 2014. Anthropometric variables such as height, weight, waist circumference(WC), hip circumference(HC), systolic blood pressure(SBP), diastolic blood pressure(DBP), and calculate the body mass index (BMI). Serum levels of fasting blood glucose (FBG) and fasting insulin (FINS), total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL) and high-density lipoprotein cholesterol (HDL) were measured and calculate the HOMA-IR. after 12hour empty-stomach in all subjects and the DNA were extracted from these samples for detecting genetic single nucleotide polymorphism. Six reproductive endocrine hormone and 75 grams of glucose tolerance test were measured for PCOS women additionaly. Women with PCOS were divided into two groups based on BMI:group A (BMI>25Kg/m2) and group B (BMI<25kg/m2). Parents of women with PCOS were accordingly categorized into group C and group D(fathers) and group E and group F(mothers).4G/5G polymorphism of PAI-1 gene were genotyped using direct sequencing protocol and Transmission disequilibrium test(TDT) was used to analyze the association between PAI-1 gene and PCOS.Results:After the TDT analyze, though the 5G allele in PAI-1 gene was overtransmitted in families, there has no statistical significance and there was no association between PAI-1 gene and PCOS. The levels of FINS, HOMA-IR and TG were significantly different between obese and lean PCOS and the parents:PCOS: INS(mIU/1)(18.91±9.80,10.24±5.11, P<0.05), HOMA-IR (4.88±2.77,2.54±1.42, P<0.05), TG(mmol/1)(1.86±1.31,1.03±0.55, P<0.05); Thefathers’s:INS(mIU/1) (9.99±6.46,5.05±2.20, P<0.05), HOMA-IR(3.20±2.49,1.30±0.61, P<0.05), TG(mmol/1) (1.83±1.24,1.38±1.07, P<0.05); The mathers’s:INS(mIU/1) (11.79±5.76,7.10±3.50, P<0.05), HOMA-IR(2.94±1.66,1.86±0.96, P<0.05) TG(mmol/1) (1.76±1.30,1.28±0.93, P<0.05). while the FBG of all groups had no signification.(P>0.05).Conclusion:No significant evidence of association or linkage was found between 4G/5G polymorphism of PAI-1 gene and PCOS, indicating that PAI-1 gene is unlikely to play a major role in the etiology of PCOS in our sample,.