O-301 Genome-wide association study identified meiotic variant associated with aneuploid pregnancy loss

Study question

Which single nucleotide variant (SNVs) are associated with aneuploid pregnancy loss?

Summary answer

We identified a SNV on MEIG1 gene, which are associated with meiosis/spermiogenesis.

What is known already

Recurrent pregnancy loss (RPL) refers to the loss of two or more pregnancies, with a frequency of 5%. Chromosomal abnormalities in embryos are found in 80% of first trimester miscarriages, 86% of which are aneuploid. Recently, embryonic aneuploidy was found to be the most common cause of RPL, with a frequency of 40-50%. Most trisomy miscarriages are of maternal origin, with errors occurring during meiosis of the oocyte. Chromosome segregation abnormalities in oocytes are thought to be an event associated with increasing maternal age, but in addition, maternal genetic causes are thought to contribute.

Study design, size, duration

A Genome wide association study (GWAS) was performed on a clinically well characterized cohort of 189 women with RPL whose previous aborted conceptus was ascertained to be an aneuploid embryo. Samples were mainly collected from 2007 to 2018 mainly at Nagoya City University Hospital. For control samples, we used 1157 samples from the population-based prospective cohorts that included fertile women.

Participants/materials, setting, methods

All patients underwent a systematic examination. Patients with antiphospholipid syndrome, an abnormal chromosome in either partner, or uterine anomaly were excluded. Patients whose previously miscarried POC exhibited triploidy or 45, X were excluded. DNA was isolated from stored EDTA-blood samples and genotyped by Axiom Japonica-array v2659,503 SNVs). For the GWAS, a chi-squared test was applied to a two-by-two contingency table in allele frequency model.

Main results and the role of chance

The mean (SD) ages and number of previous miscarriages of the patients were 36.8 (4.3) and 3.09 (1.13). GWAS data revealed 5 SNVs with suggestive significance (p < 9.46e-06). The SNVs that showed the most significant associations (P = 1.06E-06, OR = 1.72) was located on meiosis/spermiogenesis associated 1 (MEIG1) gene under an allelic model after Bonferroni correction considering the number of analyzed SNVs. The SNV rs7908491 was reported as a splicing QTL in the MEIG1 gene, which is a meiosis/meiosis-associated factor and is plausibly associated with chromosome aneuploidy. This is the first GWAS in patients with RPL caused by aneuploidy.

Limitations, reasons for caution

Since this study was conducted in a single center and had a small sample size, it needs to be replicated in different centers with more subjects and on an international scale. Whole genome imputation analysis will be performed to detect SNVs with more significant associations.

Wider implications of the findings

Our findings demonstrate that a specific genotype of MEIG1 gene can be a risk factor for aneuploid pregnancy loss. The establishment of clinically applicable maternal germ cell markers could identify groups for whom PGT would be more useful or provide patients with counseling that provides prognostic information about pregnancy.

Trial registration number

not applicable

P–377 Association between antinuclear antibodies and pregnancy prognosis in recurrent pregnancy loss patients

Study question

Can antinuclear antibody (ANA) affect the subsequent live birth rate in patients with recurrent pregnancy loss (RPL) who have no antiphospholipid antibodies (aPLs)?

Summary answer

ANA did not affect the pregnancy prognosis of RPL women.

What is known already

The prevalence of ANA is well-known to be higher in RPL patients. Our previous study found no difference in the live birth rates of ANA-positive and -negative patients who had no aPLs. Higher miscarriage rates were also reported in ANA-positive patients compared to ANA-negative patients with RPL. The RPL guidelines of the ESHRE state that “ANA testing can be considered for explanatory purposes.” However, there have been a limited number of studies on this issue and sample sizes have been small, and the impact of ANA on the pregnancy prognosis is unclear.

Study design, size, duration

An observational cohort study was conducted at Nagoya City University Hospital between 2006 and 2019. The study included 1,108 patients with a history of 2 or more pregnancy losses.

Participants/materials, setting, methods

4D-Ultrasound, hysterosalpingography, chromosome analysis for both partners, aPLs and blood tests for ANA and diabetes mellitus were performed before a subsequent pregnancy. ANAs were measured by indirect immunofluorescence. The cutoff dilution used was 1:40. In addition, patients were classified according to the ANA pattern on immunofluorescence staining. Live birth rates were compared between ANA-positive and ANA-negative patients after excluding patients with antiphospholipid syndrome, an abnormal chromosome in either partner and a uterine anomaly.

Main results and the role of chance

The 994 patients were analyzed after excluding 40 with a uterine anomaly, 43 with a chromosome abnormality in either partner and 32 with APS. The rate of ANA-positive patients was 39.2% (390/994) when the 1: 40 dilution result was positive. With a 1:160 dilution, the rate of ANA-positive patients was 3.62% (36/994). The live birth rate was calculated for 798 patients, excluding 196 patients with unexplained RPL who had been treated with any medication.

With the use of the 1: 40 dilution, the subsequent live birth rates were 71.34% (219/307) for the ANA-positive group and 70.67% (347/491) for the ANA-negative group (OR, 95%CI; 0.968, 0.707–1.326). After excluding miscarriages with embryonic aneuploidy, chemical pregnancies and ectopic pregnancies, live birth rates were 92.41% (219/237) for the ANA-positive group and 92.04% (347/377) for the ANA-negative group (0.951, 0.517–1.747). Using the 1:160 dilution, the subsequent live birth rates were 84.62% (22/26) for the ANA-positive group, and 70.47% (544/772) for the ANA-negative group (0.434, 0.148–1.273).

Subgroup analyses were performed for each pattern on immunofluorescence staining, but there was no significant difference in the live birth rate between the two groups.

Limitations, reasons for caution

The effectiveness of immunotherapies could not be evaluated. However, the results of this study suggest that it is not necessary.

Wider implications of the findings: The measurement of ANA might not be necessary for the screening of patients with RPL who have no features of collagen disease.

Trial registration number

Not applicable

P-377 Association between antinuclear antibodies and pregnancy prognosis in recurrent pregnancy loss patients

Study question

Can antinuclear antibody (ANA) affect the subsequent live birth rate in patients with recurrent pregnancy loss (RPL) who have no antiphospholipid antibodies (aPLs)?

Summary answer

ANA did not affect the pregnancy prognosis of RPL women.

What is known already

The prevalence of ANA is well-known to be higher in RPL patients. Our previous study found no difference in the live birth rates of ANA-positive and -negative patients who had no aPLs. Higher miscarriage rates were also reported in ANA-positive patients compared to ANA-negative patients with RPL. The RPL guidelines of the ESHRE state that “ANA testing can be considered for explanatory purposes.” However, there have been a limited number of studies on this issue and sample sizes have been small, and the impact of ANA on the pregnancy prognosis is unclear.

Study design, size, duration

An observational cohort study was conducted at Nagoya City University Hospital between 2006 and 2019. The study included 1,108 patients with a history of 2 or more pregnancy losses.

Participants/materials, setting, methods

4D-Ultrasound, hysterosalpingography, chromosome analysis for both partners, aPLs and blood tests for ANA and diabetes mellitus were performed before a subsequent pregnancy. ANAs were measured by indirect immunofluorescence. The cutoff dilution used was 1:40. In addition, patients were classified according to the ANA pattern on immunofluorescence staining. Live birth rates were compared between ANA-positive and ANA-negative patients after excluding patients with antiphospholipid syndrome, an abnormal chromosome in either partner and a uterine anomaly.

Main results and the role of chance

The 994 patients were analyzed after excluding 40 with a uterine anomaly, 43 with a chromosome abnormality in either partner and 32 with APS. The rate of ANA-positive patients was 39.2 % (390/994) when the 1: 40 dilution result was positive. With a 1:160 dilution, the rate of ANA-positive patients was 3.62 % (36/994). The live birth rate was calculated for 798 patients, excluding 196 patients with unexplained RPL who had been treated with any medication.

With the use of the 1

40 dilution, the subsequent live birth rates were 71.34 % (219/307) for the ANA-positive group and 70.67 % (347/491) for the ANA-negative group (OR, 95%CI; 0.968, 0.707-1.326). After excluding miscarriages with embryonic aneuploidy, chemical pregnancies and ectopic pregnancies, live birth rates were 92.41 % (219/237) for the ANA-positive group and 92.04 % (347/377) for the ANA-negative group (0.951, 0.517-1.747).

Using the 1:160 dilution, the subsequent live birth rates were 84.62 % (22/26) for the ANA-positive group, and 70.47 % (544/772) for the ANA-negative group (0.434, 0.148-1.273).

Subgroup analyses were performed for each pattern on immunofluorescence staining, but there was no significant difference in the live birth rate between the two groups.

Limitations, reasons for caution

The effectiveness of immunotherapies could not be evaluated. However, the results of this study suggest that it is not necessary.

Wider implications of the findings

The measurement of ANA might not be necessary for the screening of patients with RPL who have no features of collagen disease.

Trial registration number

not applicable

Novel intramedullary plug with sliding mechanism used in revision total knee arthroplasty

A novel intramedullary plug with sliding mechanism has been developed and evaluated clinically in the settings of revision total knee arthroplasty (TKA). The new plug consists of a pair of specially designed components. Each component is shaped like an obliquely cut cylinder. Postoperative plain radiographs of 8 arthroplasties that include 7 stemmed femoral components and 6 stemmed tibial components (total 13 regions) were examined. No radiolucent line between the cement and the cortical bone was observed. Plugging was complete in 11 regions. No migration of the plug was observed. Slight leak of the cement was observed in 2 of 7 femoral components, but not found in tibial components. Our study demonstrated the efficacy of the plug in occluding the femoral and tibial canal completely in 11 out of 13 regions in revision TKAs.