Mixed gonadal dysgenesis with gonadoblastoma diagnosed by prophylactic laparoscopic gonadectomy: A case report

Mixed gonadal dysgenesis (MGD) is a disorder of sex development caused by mosaicism of the Y chromosome, represented by 45,X/46,XY. Prophylactic gonadectomy is recommended as soon as possible after its diagnosis, owing to a high risk of malignancy. In the present case, a 21-year-old woman presented with primary amenorrhea. Although the patient's external genitalia were female, the patient exhibited a hypoplastic uterus, wherein the ovaries were difficult to identify. The patient's height was 146 cm; they had cubitus valgus and webbing of the neck, leading to the consideration of a disorder of sex development. Chromosomal examination revealed 45,X/46,XY mosaicism. Thus, the patient was diagnosed with MGD. After thorough counseling, laparoscopic bilateral gonadectomy was performed. Pathological examination revealed a gonadoblastoma of the left gonad. Postoperatively, the patient had no recurrence and continued on Kaufmann therapy. In conclusion, prophylactic gonadectomy is recommended immediately following a diagnosis of MGD; however, the timing of the surgery should be carefully considered and adequate counseling should be conducted by a multidisciplinary team.

Comparative Analysis of Two NGS-Based Platforms for Product-of-Conception Karyotyping

Cytogenetic information about the product of conception (POC) is important to determine the presence of recurrent chromosomal abnormalities that are an indication for preimplantation genetic testing for aneuploidy or structural rearrangements. Although microscopic examination by G-staining has long been used for such an evaluation, detection failures are relatively common with this method, due to cell-culture-related issues. The utility of low-coverage whole-genome sequencing (lcWGS) using short-read next-generation sequencing (NGS) has been highlighted recently as an alternative cytogenomic approach for POC analysis. We, here, performed comparative analysis of two NGS-based protocols for this purpose based on different short-read sequencers (the Illumina VeriSeq system using a MiSeq sequencer and the Thermo Fisher ReproSeq system using an Ion S5 sequencer). The cytogenomic diagnosis obtained with each NGS method was equivalent in each of 20 POC samples analyzed. Notably, X chromosome sequence reads were reduced in some female samples with both systems. The possibility of low-level mosaicism for monosomy X as an explanation for this was excluded by FISH analysis. Additional data from samples with various degrees of X chromosome aneuploidy suggested that it was a technical artifact related to X chromosome inactivation. Indeed, subsequent nanopore sequencing indicated that the DNA in the samples showing the artifact was predominantly unmethylated. Our current findings indicate that although X chromosome data must be interpreted with caution, both the systems we tested for NGS-based lcWGS are useful alternatives for the karyotyping of POC samples.

Truncating variants of the sterol recognition region of SHH cause hypertelorism phenotype rather than hypotelorism-holoprosencephaly

Sonic hedgehog signaling molecule (SHH) is a key molecule in the cilia-mediated signaling pathway and a critical morphogen in embryogenesis. The association between loss-of-function variants of SHH and holoprosencephaly is well established. In mice experiments, reduced or increased signaling of SHH have been shown to be associated with narrowing or excessive expansion of the facial midline, respectively. Herein, we report two unrelated patients with de novo truncating variants of SHH presenting with hypertelorism rather than hypotelorism. The first patient was a 13-year-old girl. Her facial features included hypertelorism, strabismus, telecanthus, malocclusion, frontal bossing, and wide widow's peak. She had borderline developmental delay and agenesis of the corpus callosum. She had a nonsense variant of SHH: Chr7(GRCh38):g.155802987C > T, NM_000193.4:c.1302G > A, p.(Trp434*). The second patient was a 25-year-old girl. Her facial features included hypertelorism and wide widow's peak. She had developmental delay and agenesis of the corpus callosum. She had a frameshift variant of SHH: Chr7(GRCh38):g.155803072_155803074delCGGinsT, NM_000193.4:c.1215_1217delCCGinsA, p.(Asp405Glufs*92). The hypertelorism phenotype contrasts sharply with the prototypical hypotelorism-holoprosencephaly phenotype associated with loss-of-function of SHH. We concluded that a subset of truncating variants of SHH could be associated with hypertelorism rather than hypotelorism.

Differential phosphorylation of two serine clusters in mouse HORMAD1 during meiotic prophase I progression

Mouse HORMAD1 is a phospho-protein involved in multiple functions during meiotic prophase I. To obtain insight into the significance of its phosphorylation, we generated phospho-specific antibodies against two serine residues, Ser307 and Ser378, representing each of two serine clusters in mouse HORMAD1. The Ser307 phosphorylation is detectable from early leptotene substage in both wild-type and Spo11-/- spermatocytes, indicating that Ser307 is a primary and SPO11-independent phosphorylation site. In contrast, the Ser378 phosphorylation is negligible at earlier substages in wild-type and Spo11-/- spermatocytes. After mid-zygotene substage, the Ser378 phosphorylation is abundant on unsynapsed chromosome axes in wild-type spermatocytes and is detected only in a part of unsynapsed chromosome axes in Spo11-/- spermatocytes. We also generated a non-phosphorylated Ser307-specific antibody and found that Ser307 is phosphorylated on sex chromosome axes but is almost entirely unphosphorylated on desynapsed chromosome axes in diplotene spermatocytes. These results demonstrated a substage-specific phosphorylation status of mouse HORMAD1, which might be associated with multiple substage-specific functions.

Breakpoints in complex chromosomal rearrangements correspond to transposase-accessible regions of DNA from mature sperm

Constitutional complex chromosomal rearrangements (CCRs) are rare cytogenetic aberrations arising in the germline via an unknown mechanism. Here we analyzed the breakpoint junctions of microscopically three-way or more complex translocations using comprehensive genomic and epigenomic analyses. All of these translocation junctions showed submicroscopic genomic complexity reminiscent of chromothripsis. The breakpoints were clustered within small genomic domains with junctions showing microhomology or microinsertions. Notably, all of the de novo cases were of paternal origin. The breakpoint distributions corresponded specifically to the ATAC-seq (assay for transposase-accessible chromatin with sequencing) read data peak of mature sperm and not to other chromatin markers or tissues. We propose that DNA breaks in CCRs may develop in an accessible region of densely packaged chromatin during post-meiotic spermiogenesis.

Mitochondrial DNA mutations can influence the post-implantation development of human mosaic embryos

Introduction: Several healthy euploid births have been reported following the transfer of mosaic embryos, including both euploid and aneuploid blastomeres. This has been attributed to a reduced number of aneuploid cells, as previously reported in mice, but remains poorly explored in humans. We hypothesized that mitochondrial function, one of the most critical factors for embryonic development, can influence human post-implantation embryonic development, including a decrease of aneuploid cells in mosaic embryos. Methods: To clarify the role of mitochondrial function, we biopsied multiple parts of each human embryo and observed the remaining embryos under in vitro culture as a model of post-implantation development (n = 27 embryos). Karyotyping, whole mitochondrial DNA (mtDNA) sequencing, and mtDNA copy number assays were performed on all pre- and post-culture samples. Results: The ratio of euploid embryos was significantly enhanced during in vitro culture, whereas the ratio of mosaic embryos was significantly reduced. Furthermore, post-culture euploid and culturable embryos had significantly few mtDNA mutations, although mtDNA copy numbers did not differ. Discussion: Our results indicate that aneuploid cells decrease in human embryos post-implantation, and mtDNA mutations might induce low mitochondrial function and influence the development of post-implantation embryos with not only aneuploidy but also euploidy. Analyzing the whole mtDNA mutation number may be a novel method for selecting a better mosaic embryo for transfer.

Increased levels of nectin-4 as a serological marker for pre-eclampsia

OBJECTIVES

Nectin-4 is a cell adhesion molecule with vital functions at adherens and tight junctions. Cumulative evidence now indicates that the NECTIN4 gene is overexpressed in a variety of cancers, and that the nectin-4 protein is both a disease marker and therapeutic target in a subset of these cancers. We previously demonstrated that NECTIN4 is overexpressed in placenta during pre-eclamptic pregnancy, which is one of the most serious obstetric disorders.

METHODS

Nectin-4 protein levels were measured in maternal sera from pregnant women with pre-eclampsia and its related disorder, unexplained fetal growth retardation.

RESULTS

Maternal serum concentrations of nectin-4 were significantly elevated in pre-eclamptic women compared with those with an uncomplicated normotensive pregnancy. However, no increase was observed in pregnancies with unexplained fetal growth retardation. Serum nectin-4 levels were higher in cases with early-onset pre-eclampsia that generally showed more severe clinical symptoms, but levels were not correlated to other clinical indicators of disease severity.

CONCLUSIONS

Nectin-4 is a potential new diagnostic and predictive biomarker for severe pre-eclampsia.

Clinical application of long-read nanopore sequencing in a preimplantation genetic testing pre-clinical workup to identify the junction for complex Xq chromosome rearrangement-related disease

OBJECTIVE

Xq chromosome duplication with complex rearrangements is generally acknowledged to be associated with neurodevelopmental disorders, such as Pelizaeus-Merzbacher disease (PMD) and MECP2 duplication syndrome. For couples who required a PGT-M (pre-implantation genetic testing for monogenic disease) for these disorders, junction-specific PCR is useful to directly detect pathogenic variants. Therefore, pre-clinical workup for PGT-M requires the identification of the junction of duplicated segments in PMD and MECP2 duplication syndrome, which is generally difficult.

METHODS

In this report, we used nanopore long-read sequencing targeting the X chromosome using an adaptive sampling method to identify breakpoint junctions in disease-causing triplications.

RESULTS

By long-read sequencing, we successfully identified breakpoint junctions in one PMD case with PLP1 triplication and in another MECP2 triplication case in a single sequencing run. Surprisingly, the duplicated region involving MECP2 was inserted 45 Mb proximal to the original position. This inserted region was confirmed by FISH analysis. With the help of precise mapping of the pathogenic variant, we successfully re-established STR haplotyping for PGT-M and avoided any potential misinterpretation of the pathogenic allele due to recombination.

CONCLUSION

Long-read sequencing with adaptive sampling in a PGT-M pre-clinical workup is a beneficial method for identifying junctions of chromosomal complex structural rearrangements.

Novel compound heterozygous mutations in the PLEC gene in a neonate with epidermolysis bullosa simplex with pyloric atresia

Epidermolysis bullosa (EB) is a heterogeneous group of inherited disorders characterized by the blistering of the skin and mucous membranes. Although the molecular basis of EB has been significantly elucidated, the precise phenotypes of the lethal types of EB have not been completely characterized. Herein, we report a severe case of EB with pyloric atresia (PA). The patient was a Japanese boy who not only had skin lesions but also various complications such as PA, dysphagia, hypotonia, infectious keratitis with corneal ulcer, obstructive uropathy and protein-losing enteropathy. Genetic analysis led to the identification of two novel compound heterozygous mutations in the last exon of the plectin (PLEC) gene. Based on this finding, EB simplex with PA was diagnosed. Immunostaining with anti-plectin antibodies revealed truncated plectin proteins lacking the C-terminus in the patient's skin. We also conducted a prenatal diagnosis in subsequent pregnancy. Our report further highlights the crucial role of plectin in many organs and provides valuable information regarding the phenotypes resulting from mutations in the PLEC gene.

The age-related required number of zygotes estimated from prior clinical studies of preimplantation genetic testing for aneuploidy (PGT-A)

Women who are undergoing preimplantation genetic testing for aneuploidy (PGT-A) often wish to know how many eggs will be required to optimize the chances of a live birth. However, no precise data on this can yet be provided during genetic counseling for this procedure. On the basis of PGT-A data from related studies and current databases, we have estimated that the number of zygotes required for a 50% chance of a live birth is 8 at age 40 but increases markedly to 21 at age 43. PGT-A markedly reduces the miscarriage rate per embryo transfer but does not alleviate the extremely high number of zygotes required for a live birth in women of an advanced maternal age. Detailed genetic counseling will therefore be desirable prior to undergoing this procedure.

The effect of early irregular cell division of human embryos on blastocyst euploidy: considerations from the subsequent development of the blastomeres by direct or reverse cleavage

OBJECTIVE

To investigate whether blastocysts that divide irregularly reduce subsequent blastocyst euploidy.

DESIGN

Retrospective study.

SETTING

Private clinic.

PATIENT(S)

A total of 122 blastocysts for which consent for disposal and research use was obtained.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Results of next-generation sequencing analysis of the blastocysts and whether blastomeres by normal or irregular divisions subsequently participated in blastocyst formation or not.

RESULT(S)

The embryos were classified according to their dynamics until the second cleavage. The blastocyst euploidy rates were 33.3% (19/57) in the normal cleavage (NC) group, 38.3% (18/47) in the direct cleavage (embryos with one cell dividing into 3 cells) (DC) group, and 72.2% (13/18) in the reverse cleavage (RC) (embryos with fused cells once divided) group. The rate of the RC group was significantly higher than that of the NC group. The blastocyst participation rate of the blastomeres were 95.6% in the NC group and 56.5% in that derived from DC of the first cleavage, and 91.7% in that of blastomeres derived from normal division of the second cleavage and 53.6% in that derived from DC of the second cleavage, both of which were significantly lower in the latter. In the RC group, the rates of fused and nonfused blastomeres were 62.1% and 87.5%, respectively, with no significant difference.

CONCLUSION(S)

The blastomeres generated by DC were often excluded from blastocyst formation, and we speculate that this is one reason why their division does not reduce blastocyst euploidy. The association between RC and euploidy of blastocysts merits further study.

Transport and Golgi organization 2 deficiency with a prominent elevation of C14:1 during a metabolic crisis: A case report

Mutations in transport and Golgi organization 2 homolog (TANGO2) have recently been described as a cause of an autosomal recessive syndrome characterized by episodes of metabolic crisis associated with rhabdomyolysis, cardiac arrhythmias, and neurodegeneration. Herein, we report a case of a one-and-a-half-year-old Japanese girl, born to nonconsanguineous parents, who presented with metabolic crisis characterized by hypoglycemia with hypoketonemia, rhabdomyolysis, lactic acidosis, and prolonged corrected QT interval (QTc) at the age of 6 months. Acylcarnitine analysis during the episode of crisis showed prominent elevation of C14:1, suggesting very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency. In addition, worsening rhabdomyolysis was observed after intravenous administration of L-carnitine. VLCAD deficiency was initially suspected; however, the enzyme activity in lymphocytes was only mildly decreased at the gene carrier level, and no mutation in the VLCAD gene (ADADVL) was detected. Subsequently, acylcarnitine analysis was nonspecific at 17-h fasting and almost normal during the stable phase. Eventually, a trio whole-exome sequencing revealed a compound heterozygous variant of two novel variants in the TANGO2 gene, a missense variant, and a deletion of exon 7. This is the first case of TANGO2 deficiency in Asians. Our case suggests that elevated C14:1 may be seen in severe metabolic crises and that the use of L-carnitine should be avoided during metabolic crises.

Antisense oligonucleotide induced pseudoexon skipping and restoration of functional protein for Fukuyama muscular dystrophy caused by a deep-intronic variant

Fukuyama congenital muscular dystrophy (FCMD) is an autosomal recessive disorder caused by fukutin (FKTN) gene mutations. FCMD is the second most common form of childhood muscular dystrophy in Japan, and the most patients possess a homozygous retrotransposal SINE-VNTR-Alu insertion in the 3′-untranslated region of FKTN. A deep-intronic variant (DIV) was previously identified as the second most prevalent loss-of-function mutation in Japanese patients with FCMD. The DIV creates a new splicing donor site in intron 5 that causes aberrant splicing and the formation of a 64-base pair pseudoexon in the mature mRNA, resulting in a truncated nonfunctional protein. Patients with FCMD carrying the DIV present a more severe symptoms, and currently, there is no radical therapy available for this disorder. In the present study, we describe in vitro evaluation of antisense oligonucleotide mediated skipping of pseudoexon inclusion and restoration of functional FKTN protein. A total of 16 19-26-mer antisense oligonucleotide sequences were designed with a 2’-O-methyl backbone and were screened in patient-derived fibroblasts, lymphoblast cells, and minigene splice assays. One antisense oligonucleotide targeting the exonic splice enhancer region significantly induced pseudoexon skipping and increased the expression of normal mRNA. It also rescued FKTN protein production in lymphoblast cells and restored functional O-mannosyl glycosylation of alpha-dystroglycan in patient-derived myotubes. Based on our results, ASO-based splicing correction should be investigated further as a potential treatment for patients with FCMD carrying the DIV.

Maple syrup urine disease due to a paracentric inversion of chr 19 that disrupts BCKDHA: A case report

Maple syrup urine disease (MSUD) is a rare autosomal recessive inherited disorder of branched-chain amino acid metabolism caused by mutations in BCKDHA, BCKDHB, and DBT that encode the E1α, E1β, and E2 subunits of the branched-chain α-ketoacid dehydrogenase (BCKD) complex. Various MSUD-causing variants have been described; however, no structural rearrangements in BCKDHA have been reported to cause the classic MSUD phenotype. Here, we describe the classic patient with MSUD with compound heterozygous pathogenic variants in BCKDHA: a missense variant (NM_000709.3:c.757G > A, NP_000700.1:p.Ala253Thr) and a paracentric inversion disrupting Intron 1 of BCKDHA, which was identified by whole-genome sequencing and validated by fluorescence in situ hybridization. Using the sequence information of the breakpoint junction, we gained mechanistic insight into the development of this structural rearrangement. Furthermore, the establishment of junction-specific polymerase chain reaction could facilitate identification of the variant in case carrier or future prenatal/preimplantation tests are necessary.

An Infant Case of Streptococcus Pneumoniae-Associated Thrombotic Microangiopathy with Heterozygous CFI Mutation and CFHR3-CFHR1 Deletion

Thrombotic microangiopathy (TMA) is a disease that causes organ damage due to microvascular hemolytic anemia, thrombocytopenia, and microvascular platelet thrombosis. Streptococcus pneumoniae-associated TMA (spTMA) is a rare complication of invasive pneumococcal infection. In addition, atypical hemolytic uremic syndrome (aHUS) is TMA associated with congenital or acquired dysregulation of complement activation. We report the case of a nine-month-old boy with refractory nephrotic syndrome complicated by spTMA in the setting of heterozygous complement factor-I (CFI) gene mutation and CFHR3-CFHR1 deletion. He repeatedly developed thrombocytopenia, anemia with schistocytes, hypocomplementemia, and abnormal coagulation triggered by infection, which manifested clinically with convulsions and an intraperitoneal hematoma. Eculizumab (a monoclonal humanized anti-C5 antibody) provided transient symptomatic benefit including improvement in thrombocytopenia; however, he developed unexplained cardiac arrest and was declared brain dead a few days later. In this report, we highlight the diagnostic challenges of this case and the causal relationship between spTMA and complement abnormalities and consider the contribution of heterozygous mutation of CFI and CFHR3-CFHR1 deletion.

A case of 46,XY disorders of sex development with congenital heart disease caused by a GATA4 variant

GATA4 is known to be a causative gene for congenital heart disease, but has also now been associated with disorders of sexual development (DSD). We here report a pathogenic variant of GATA4 in a 46,XY DSD patient with an atrial septal defect, identified by whole-exome sequencing to be c.487C>T (p.Pro163Ser). This mutation resulted in reduced transcriptional activity of the downstream gene. When we compared this transcriptional activity level with other GATA4 variants, those that had been identified in patients with cardiac defects and DSD showed less activity than those in patients with cardiac defect only. This suggests that the normal development of the heart requires more strict regulation of GATA4 transcription than testicular development. Further, when the different variants were co-expressed with wild-type, the transcriptional activities were consistently lower than would be expected from an additive effect, suggesting a dominant-negative impact of the variant via dimer formation of the GATA4 protein. Since these pathogenic GATA4 variants are occasionally identified in healthy parents, a threshold model of quantitative traits may explain the cardiac defect or DSD phenotypes that they cause.

A case of early onset adenocarcinoma associated with colorectal polyposis with an unknown germline mutation

Background

Typically, in cases of adenomatous polyposis, colorectal cancer develops in the third or fourth decade of life. We report the case of a female patient with colorectal polyposis who developed adenocarcinoma at 8 years of age.

Case presentation

An 8-year-old girl was admitted with a 4-year history of occasional bloody stools. Colonoscopy revealed colon polyposis and histopathological assessment confirmed a well-differentiated adenocarcinoma in the adenomatous polyps, so laparoscopy-assisted proctocolectomy was performed in the lithotomy position by a simultaneous abdominal and anal approach. To completely resect the rectal mucosa, excision was commenced just distal to the dentate line. After the mucosal resection up to the peritoneal reflection level, an inverted muscular cuff was cut circumferentially, and the terminal ileum was pulled through the muscular cuff and anastomosed to the anal canal. Histopathology revealed multiple adenomatous polyps and scattered well-differentiated tubular adenocarcinomas (tub1) in the adenomatous polyps and the non-polypoid mucosal lesions. Because complete resection was achieved, additional adjuvant chemotherapy was not administered. Polymerase chain reaction (PCR)-direct sequencing of the entire coding region and the exon–intron junctions, and real-time PCR of DNA extracted from blood cells, revealed no mutations of either APC or MUTYH. No deletions, duplications, translocations or inversions of APC, MUTYH and GREM1 genes were found using multiplex ligation-dependent probe amplification (MLPA) and G-banding analysis. Multi-gene panels sequencing for polyposis syndromes or hereditary colorectal cancers, and trio-whole exome sequencing was conducted. However, no candidate pathogenic variants of genes were detected in de novo dominant or autosomal recessive model. Somatic mutation of APC was not detected in 4 polyps by loss of heterozygosity analysis at a single nucleotide polymorphism in intron 14. The patient has remained disease-free for 5 years. Currently, the patient is on loperamide and passes stool 5 times/day without any soiling.

Conclusions

The genetic analysis suggests that she may have a germline mutation at unscreened region of these genes or in unidentified FAP gene. The patient will be carefully followed up for residual rectal carcinoma and for the development of other cancers.

Longitudinal study of the vaginal microbiome in pregnancies involving preterm labor

Objectives

Alterations in the vaginal bacterial flora reflect the status of various obstetric conditions and are associated with mechanisms that underlie certain pregnancy-associated complications. These changes are also a predictive biomarker for clinical outcomes of these adverse events.

Methods

We examined the vaginal microbiome in samples from pregnant Japanese women with preterm labor.

Results

The microbiota composition in preterm delivery (PD) samples differed from those of control or threatened preterm delivery (TPD) samples in principal component analysis. An increase in Firmicutes and a decrease in Actinobacteria were significantly associated with PD only (both P<0.01). In the Firmicutes phylum, Lactobacillus tended to be abundant, and the abundance of L. iners and L. crispatus was especially high, whereas the L. gasseri population was low in PD samples. Longitudinal analysis showed that the abundance of L. iners decreased after commencing tocolytic treatment in TPD samples compared with before treatment, but it remained high in PD samples.

Conclusions

The vaginal microbiome may be a useful prognostic indicator of preterm labor and a monitoring tool for tocolytic treatment to prevent preterm birth.

P-545 The age-related required number of zygotes estimated from prior clinical studies of preimplantation genetic testing for aneuploidy (PGT-A)

Study question

How many eggs will be required to optimize the chances of a live birth with or without PGT-A?

Summary answer

The number of zygotes required for live birth is higher in women with an advanced age, and the use of PGT-A does not provide improvement.

What is known already

Women who are undergoing PGT-A often wish to know how many eggs will be required to optimize the chances of a live birth. This important information could be provided as part of prior genetic counseling, but there are no precise data on this at present. If the number of eggs required to give the best chance of a successful live birth was known, treatment plans with or without PGT-A could be better determined.

Study design, size, duration

We estimated the optimal number of eggs required for IVF treatment with PGT-A to produce at least a single live birth, stratified by maternal age, on the basis of information from prior studies and in current databases.

Participants/materials, setting, methods

We derived our calculation parameters from three prior large-scale clinical investigations associated with PGT-A. We estimated a live birth rate using the following factors: rate of zygotes that develop a useful blastocyst, euploid rate in PGT-A, and the live birth rate after euploid embryo transfer. All of these factors were assumed to be statistically independent in this study for the purposes of our calculations and the live birth rate per single zygote was calculated.

Main results and the role of chance

The estimations in our present analyses however indicate a probability of less than 10% that woman over 40 years of age will have a live birth from a single zygote, regardless of whether PGT-A is performed or not. We used a negative binomial distribution approach to calculate how many zygotes are needed to obtain at least one live birth. The plot of these results is provided in Figure 2. To achieve a 50% chance of getting at least one live birth, patients required 8 zygotes at age of 40 and 21 zygotes at the age of 43. Furthermore, to achieve an 80% chance of obtaining a live birth, our calculations estimate that 18 and 47 zygotes would be required at these two ages, respectively, which would be challenging to achieve. On the other hand, by avoiding unnecessary transplants using PGT-A, women may have to wait a shorter period to accomplish a live birth or may be able to avoid wasting their limited remaining reproductive period, particularly if they are older than 42.

Limitations, reasons for caution

The reference data from PGT-A studies that have estimated of the live birth rate include chromosomal quantitative PCR, microarray analysis, and next generation sequencing (NGS). There is a high possibility that the embryos designated as “euploid” in those studies include mosaic embryos, which represents a limitation of our present meta-analysis.

Wider implications of the findings

More details on the clinical outcomes of PGT-A will be revealed as clinical studies progress in the future. It is our hope that the results of this present study will assist with future genetic counseling strategies for PGT-A in the meantime.

Trial registration number

not applicable

P-131 The fate of irregularly divided blastomeres: why does “Direct cleavage” reduce blastocyst development rate but not blastocyst euploid rate?

Study question

How do the blastomeres formed by direct cleavage (dynamics of one cell dividing into three or more cells) subsequently develop?

Summary answer

About half of the blastomeres by direct cleavage did not form blastocysts.

What is known already

There are many reports that embryos with direct cleavage in the early development have a lower blastocyst development rate because direct cleavage produces chromosomal abnormal cells. However, when such embryos develop into blastocysts, there have been some reports that the transfer pregnancy rate and euploid rate did not decrease, but the reasons for this have not been clarified.

Study design, size, duration

This is a retrospective study of 89 blastocysts obtained during 2013-18. These embryos were those that patients requested to be discarded and consented to be used in this study. All target embryos were time-lapse monitored by EmbryoScope (Vitrolife, Sweden), and several trophectoderms were biopsied and examined for euploidy.

Participants/materials, setting, methods

The target embryos were classified into three groups: embryos with normal first and second cleavage (NC group), embryos with irregular division (one cell dividing into three or more cells) called direct cleavage at the first cleavage (DC1 group), and embryos with direct cleavage of one blastomere at the second cleavage (DC2 group). It was recorded whether the blastomeres of the embryos subsequently developed into blastocysts or not. NGS analysis was performed on the embryos.

Main results and the role of chance

The target embryos were classified as 48 in the NC group, 32 in the DC1 group, and 9 in the DC2 group. Whether the blastomeres in the target embryos subsequently formed blastocysts or not was recorded one by one by time-lapse images, resulting in the blastomeres’ blastocyst formation rate was 95.1% in the NC group and 55.9% in the DC1 group, which was significantly lower in the DC1 group (P &lt; 0.01). In the DC2 group, blastomeres formed by normal division and those by direct cleavage at the second cleavage were recorded separately, and the blastocyst formation rate was 90.8% for normal cleavage blastomeres and 46.0% for direct cleavage blastomeres, with significantly lower rates for direct cleavage blastomeres (P &lt; 0.01). Therefore, about half of the blastomeres generated by direct cleavage at the first or second cleavage did not form blastocysts. The results of NGS analysis were as follows: NC group: 35.4% euploid, 45.8% aneuploid, and 18.8% mosaic; DC1 group: 37.5%, 53.1%, and 9.4%, respectively; and DC2 group: 55.6%, 33.3%, and 11.1%, respectively. There was no significant difference in any of the items, suggesting that direct cleavage does not affect the euploidy of blastocysts.

Limitations, reasons for caution

For the purpose of NGS analysis, all the target embryos in this study were blastocysts, but if all the cultured embryos were included, arrested embryos would be included, which would probably result in more blastomeres formed by direct cleavage not developing into blastocysts.

Wider implications of the findings

The blastomeres generated by direct cleavage were often excluded from blastocyst formation. This may be an exclusion of chromosomally abnormal cells and may be one of the reasons why direct cleavage decreases blastocyst development rate but does not decrease blastocyst euploid rate.

Trial registration number

not applicable

Incontinentia pigmenti inherited from a father with a low level atypical IKBKG deletion mosaicism: a case report

Background

Incontinentia pigmenti (IP) is an X-liked dominant genodermatosis caused by mutations of the IKBKG/NEMO gene. IP is mostly lethal in males in utero, and only very rare male cases with a somatic mosaic mutation or a 47,XXY karyotype have been reported.

Case presentation

We here report a case of an IKBKG gene deletion in a female infant presenting with a few blisters and erythema in her upper arms at birth. MLPA analysis revealed a rare 94 kb deletion in this patient, encompassing the IKBKG gene and IKBKGP pseudogene. PCR analysis indicated the presence of Alu elements at both ends of the deletion, suggesting non-allelic homologous recombination as an underlying mechanism. Notably, a low-level mosaic deletion was identified in her father’s peripheral blood leukocytes by PCR, suggesting a rare father-to-daughter transmission of IP.

Conclusion

In family studies for an apparently sporadic IP case, parental analysis that includes the father is recommended due to the possibility of male mosaicism.

Incidental detection of retained oil-based hysterosalpingography contrast medium on postoperative postpartum radiography: A case report

Hysterosalpingography is widely performed in assisted reproductive technology. We present a rare case of contrast medium retention which was incidentally found and mimicked a retained surgical instrument. A medical history of treatment for infertility can facilitate the differential diagnosis of abnormal findings on post-caesarean section radiography.

Experimental method for haplotype phasing across the entire length of chromosome 21 in trisomy 21 cells using a chromosome elimination technique

Modern sequencing technologies produce a single consensus sequence without distinguishing between homologous chromosomes. Haplotype phasing solves this limitation by identifying alleles on the maternal and paternal chromosomes. This information is critical for understanding gene expression models in genetic disease research. Furthermore, the haplotype phasing of three homologous chromosomes in trisomy cells is more complicated than that in disomy cells. In this study, we attempted the accurate and complete haplotype phasing of chromosome 21 in trisomy 21 cells. To separate homologs, we established three corrected disomy cell lines (ΔPaternal chromosome, ΔMaternal chromosome 1, and ΔMaternal chromosome 2) from trisomy 21 induced pluripotent stem cells by eliminating one chromosome 21 utilizing the Cre-loxP system. These cells were then whole-genome sequenced by a next-generation sequencer. By simply comparing the base information of the whole-genome sequence data at the same position between each corrected disomy cell line, we determined the base on the eliminated chromosome and performed phasing. We phased 51,596 single nucleotide polymorphisms (SNPs) on chromosome 21, randomly selected seven SNPs spanning the entire length of the chromosome, and confirmed that there was no contradiction by direct sequencing.

Novel large deletion involving EVC and EVC2 in Ellis-van Creveld syndrome

Ellis-van Creveld syndrome is an autosomal recessive skeletal dysplasia that is characterized by thoracic hypoplasia, polydactyly, oral abnormalities, and congenital heart disease. It is caused by pathogenic variants in the EVC or EVC2 genes. We report a case of a newborn with a compound heterozygous variant comprising NM_147127.5: c.1991dup:[p.Lys665Glufs*10] in the EVC2 gene and a novel large deletion involving exon 1 in EVC and exons 1-7 in EVC2.