Study on the Association Between SXCI and RM and the Possible Genetic Mechanism

Study Overview
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Brief Summary
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To determine whether there is higher incidence of skewed X chromosome inactivation(SXCI) in the recurrent miscarriage(RM) population compared with normal population, and verify the existing hypothesis of the possible genetic mechanisms underlying the association between SXCI and RM.

Detailed Description
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Recurrent spontaneous abortion (RSA), defined as 2 or more consecutive pregnancy losses before 20-22 weeks of gestation, is a multifactorial disorder that affects about 5% of all couples.In up to 50% of women who have experienced RSA, the cause still remains unexplained, with genetic problem proposed as a main cause. X chromosome inactivation (XCI) is a physiological phenomenon in female mammals for 'dosage compensation' of X-linked genes with males. A normal female is mosaic, with about one-half of her somatic cells expressing the paternal derived X and the remainder of her cells using maternal X. In some situations, however, the inactivation is not random, resulting in a female having most or even all her somatic cells inactivating the same X chromosome from either paternal or maternal resource, which is known as skewed X-chromosome inactivation (SXCI).Evidence of an association between skewed X chromosome inactivation (SXCI) and idiopathic recurrent spontaneous abortion (RSA) is conflicting. This is a single-center observational case-control trial to determine whether there is higher incidence of skewed X chromosome inactivation(SXCI) in the recurrent miscarriage(RM) population compared with normal population, and verify the existing hypothesis of the possible genetic mechanisms underlying the association between SXCI and RM.

Official Title
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Study on the Association Between Skewed X Chromosome Inactivation(SXCI) and Recurrent Miscarriage(RM) and the Possible Genetic Mechanism

Conditions
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Infertility Female, Recurrent Miscarriage

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 1) regular menstrual cycles and normal level of E2, P, FSH, LH, T, RPL in the early follicular phase; 2) no history of gynecologic or other pelvic operations; 3) no history of hormone medicine application in the last 3 months; 4) no history of poison contact; 5) normal uterine and adnexal ultrasonography; 6) TORCH(-), chlamydia(-), mycoplasma(-), normal leucorrhoea routine, anti-phospholipid antibody (-), antinuclear antibody(-); 7) for the couple, no blood type incompatibility or ABO antibody IgG≤1：64 and normal blood chromosome analysis; 8) condoms are used for contraception. Exclusion Criteria: 1) BMI<18.5 or >24.9; 2) hydrosalpinx without operation; endometriosis; polycystic ovary syndrome; adenomyosis; uterine leiomyomata(submucous myoma or non-submucous myoma which size was exceed 4cm and/or with the compressed endometrium);uterine cavity lesions(such as uterine malformation, intrauterine adhesions, the septate uterus, endometritis etc); 3) the former abortion is because of luteal phase defect without treatment; 4) FSH≥12IU/L or AMH<1.2ng/ml 5) thyroid dysfunction or increased CA125 level; 6) acute inflammation of genitourinary system or STD carriers; 7) unable to comply with the study procedures.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 43 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| RM<br>Women 18-43 years of age who are scheduled for IVF or ICSI with a history of recurrent spontaneous abortion (miscarriage occurred earlier than 22 weeks of gestation for equal or greater than 3 times) in our IVF institute. | |
| Control<br>Normal females who are visiting Shanghai JIAI genetics and IVF institute for IVF/ICSI because of only male factor. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| degree of X chromosome inactivation skewing |  | Within 3 months after blood collection | 
| percentage of extremely skewed X chromosome inactivation(SXCI>90%) in each group |  | Within 3 months after blood collection |