Family-based And Case-control Studies On The Association Of MCF2L2 Gene With Polycystic Ovary Syndrome

Partâ… Clinical analysis on different subtypes of women with polycystic ovary syndromeObjective:Polycystic ovary syndrome(PCOS) is a complex and heterogeneous disorder that is characterized by oligomenorrhea or amenorrhea,hyperandrogenism, multiple small subcapsular cystic follicles in the ovary on ultrasonography.But,each of these clinical manifestations is not specific to PCOS,and the heterogeneity seriously hampers the research process of its etiology,pathology,diagnosis and treatment.The aim of this research was to compare the clinical presentation,hormonal profile and metabolic abnormalities in subgroups of women with PCOS and to provide evidence in order to further to understand the pathogenesis of polycystic ovary syndrome.Methods:A total of 638 consecutive unrelated Chinese women with PCOS were randomly recruited from the Reproductive Medical Center at Shandong Provincial Hospital,Shandong University,from September 2006 to February 2008.Body height, body weight,waist circumference and hip circumference were measured,and the body mass index(BMI) was calculated.Endocrine and insulin levels were measured using chemiluminescence's methods.Blood lipid and sugar were measured using biochemical equipment,and homeostasis model assessment for insulin resistance (HOMA-IR) was calculated.Then the patients were divided into different groups according to different markers,and the results were compared between the different groups.Results:(1) In 638 PCOS patients,the ratio of patients with BMI≥25kg/m² were 46.6%.Patients with waist circumference≥80cm were 62.1%.Patients with hyperandrogenism were 85.7%.Patients with abnormal fasting insulin level were 6%. Patients with abnormal fasting glucose level were 13.9%.Patients with HOMA-IR≥1.66 were 51.4%.Patients with abnormal CHO level were 21.3%,Patients with abnormal TG level were 20.8%.Patients with abnormal LDL level were 16.6%. Patients with hypertension were 15%.(2)The PCOS patients were divided into two groups according to the waist circumference.The age,fasting blood sugar and insulin levels,30 min,60 min,120min sugar and insulin levels after 75g glucose load, HOMA-IR and blood lipid level of the central obese PCOS group(BMI≥25kg/m²) were significantly higher than those of non-central obese group(P＜0.01).There was no difference in level of 180min sugar between these two groups.The LH,FSH and PRL level in non-central obese group were higher than that of the central obese group (P＜0.05).The E₂ level of the non-central obese PCOS group were higher than that of central obese group,but the difference in the critical level(P=0.05).(3) The PCOS patients were divided into two groups according to the BMI.The age,fasting blood sugar and insulin levels,30 min,60 min,120min,180min sugar and insulin levels after 75g glucose load,HOMA-IR and blood lipid level of the obese PCOS group (BMI≥25kg/m²) were significantly higher than those of non-obese group(P＜0.01). However,the LH,FSH,E₂ and PRL level in non-obese group were higher than those of the obese group(P＜0.05).(4) The PCOS patients were divided into two groups according to the HOMA-IR.The BMI,waist circumference and hip circumference, blood lipid level of the IR group was higher than that of the non-IR group,the difference between the two groups was notable(P＜0.01).But the LH and FSH level in the non-IR group was significantly higher than that of the IR group(P＜0.01).(5) The PCOS patients were divided into two groups according to the fasting testosterone levels.The LH level in the hyperandrogenemia(HA) group was significantly higher than that of the non-HA group(P＜0.01).But,in other aspects there were no difference between the two groups.(6) Correlation analysis showed that,the BMI and waist of PCOS patients were demonstrated to be positive correlated with HOMA-IR,CHO, LDL and TG.There were no correlation between BMI and waist and the level of T and LH.The blood LH level showed a negative correlation between BMI and waist.Conclusions:(1) There are many phenotypes of metabolism syndrome in PCOS patients,including obesity,hyperandrogenism,insulin resistance,abnormal lipid metabolism and hypertension.(2) There were differences in the basic characteristics of the disease and risk of metabolic complications between subgroups of PCOS patients grouped according to waist circumference,BMI and HOMA-IR.However,there were no difference between HA group and non-HA group except the blood LH level.(3) Obesity,especially abdominal obesity in PCOS patients is closely related with insulin resistance.Obesity showed a positive correlation with lipid metabolism abnormality.(4) PCOS is a highly heterogeneous disease,and the clinical features on different subgroups of women with PCOS have significant differences. Partâ…¡Case-control based association study between common polymorphisms in the MCF2L2 gene and polycystic ovary syndromeObjective:The strong clinical,phenotypic and pathophysiology overlap between type 2 diabetes(T2D) and polycystic ovary syndrome(PCOS) promotes a powerful argument for overlapping etiological determinants underlying the two conditions. MCF2L2 gene is closely related with T2D.The object of the study was to determine whether the variants of the MCF.2 cell line derived transforming sequence-like 2 (MCF2L2) gene are associated with Chinese women with PCOS in a large, homogeneous,and well-characterized cohort.Methods:A large sample of Chinese PCOS(n=638) women and a control group (n=559) of healthy women was studied.Three valid single nucleotide polymorphisms (SNPs),i.e.rs35368790,rs35069869 and rs684846 in the MCF2L2 gene were studied using a TaqMan assay that incorporates minor groove binding(MGB) probe technology.To validate the TaqMan MGB method,5%genotyped samples were randomly selected as duplication with a direct sequencing protocol and the reproducibility was 100%.Endocrine,biochemical indicator,oral glucose tolerance test(OGTT),body height,body weight,waist circumference and hip circumference were measured,and the body mass index(BMI),waist-to-hip ratio(WHR) and homeostasis model assessment for insulin resistance(HOMA-IR) were calculated.The subjects were divided into different groups according to BMI,waist,IR and different genotype,and then the results were compared between the different groups.Results:(1) The genotype distributions and allele frequencies of these 3 SNPs in both the patient and control groups followed Hardy-Weinberg equilibrium.The minor allele frequency for rs35368790,rs35069869 and rs684846 in PCOS cases was respectively 0.115,0.276 and 0.122,similar to that seen in the control groups(0.114,0.296 and 0.114).(2) No significant differences in genotype distributions and allele frequencies of the three SNPs were observed when the PCOS and the control groups were compared.However,we found that after correcting confounding factors such as age, BMI,waist circumference and hip circumference and BP,one of the SNP markers(rs35368790)was significantly associated with the specific subgroups of PCOS patients(waist circumference＜80cm;P=0.008,OR=1.952,95%CI:1.188～3.206).(3) Chi square test showed that,no significant differences in genotype distributions and allele frequencies of the SNP rs35069869 and rs684846 were observed.But the frequency of G of rs35368790 was higher in central obese group than in non-central obese group(x²=4.81,p=0.03);Furthermore,there were significant differences in the genotype distributions and allele frequencies of rs35368790 between IR group and non-IR group(x²=6.35,p=0.04;x²=5.61,p= 0.02).(4) Analysis of covariance(ANCOVA) was performed to explore the relationship of genotype to quantitative phenotype.The data suggest that the SNP rs35368790 and rs35069869 had no impact on clinical and biochemical characteristics of the PCOS women.However there were significant differences in fasting glucose level and HOMA-IR in the rs684846 genotype of women with PCOS.The PCOS patients with the CC genotype had significantly higher fasting glucose level and HOMA-IR than those with CT genotype(F=6.28,P=0.002;F=4.66,P=0.009).(5) To evaluate the relationship between SNPs,pair-wise LD statistics D' and correlation coefficients r² were calculated using Haploview version 4.0.The value of linkage disequilibrium was D'＜0.5 and r²ï¼œ0.05.Conclusions:The SNP rs35368790 was significantly associated with PCOS women whose waist circumferences are smaller than 80cm and maybe a marking locus of lean PCOS.The linkage disequilibrium was not found in SNP rs35368790,rs35069869 and rs684846. Partâ…¢Family-based transmission disequilibrium association study of the MCF2L2 gene and polycystic ovary syndromeObjective:We used family-based analysis of transmission disequilibrium test(TDT) to control population substructure and genetic mismatching by an appropriate "internal control" and to further investigate the relationship between MCF2L2 gene and polycystic ovary syndrome.Methods:PCOS probands were ascertained from the Center for Reproductive Medicine,Shandong Provincial Hospital,a teaching hospital affiliated to Shandong University,Jinan,China during the period from July 2007 to February 2009.A total of 152 PCOS family trios[parents and an affected daughter(proband),456 members] were recruited who were Han Chinese origins.Patients' parents were all randomly mated and there were no kinship among these pedigrees.Some of them were recruited in our Center for Reproductive Medicine and others were collected at their home if they could not come in person.Then the whole-blood samples of the probands and their parents were collected and stored in -80℃.Three SNPs(rs35368790,rs35069869 and rs684846) in the MCF2L2 gene were genotyped using a TaqMan MGB technology and direct sequencing protocol.Results:(1) The genotype distributions and allele frequencies of these 3 SNPs in PCOS nuclear family followed Hardy-Weinberg equilibrium.(2) The family delivery and distribution characteristics of MCF2L2 gene show that in SNP rs35368790 the genotypes of ninety four core family parents are homozygous and 58 core family parents' genotypes are heterozygous.Similarly,in SNP rs35069869 and rs684846,the homozygous families of parents' genotypes were 49 and 90,and 103 and 62 core family parents' genotypes are heterozygous respectively.(3) In SNP rs35368790,a significant transmission disequilibrium was found from heterozygous parents onto patients in our 152 trios analyzed by TDT(x²=7.118,p=0.008),G allele transmission being too increased super to C allele.However.there were no transmission disequilibrium in SNP rs35069869(x²=3.645,p=0.056) and rs684846(x²=1.429, p=0.232).(4) The linkage disequilibrium was not found in SNP rs35368790. rs35069869 and rs684846.Conclusions:The MCF2L2 gene most likely confers the risk susceptibility to PCOS among Han Chinese women.Replication genetic studies in other populations and further functional analyses are needed to explore the role of MCF2L2 in the etiology of PCOS.