A novel multifunctional haplotyping-based preimplantation genetic testing for different genetic conditions.

STUDY QUESTION: Is there an efficient and cost-effective detection platform for different genetic conditions about embryos? SUMMARY ANSWER: A multifunctional haplotyping-based preimplantation genetic testing platform was provided for detecting different genetic conditions. WHAT IS KNOWN ALREADY: Genetic disease and chromosomal rearrangement have been known to significantly impact fertility and development. Therefore, preimplantation genetic testing for aneuploidy (PGT-A), monogenic disorders (PGT-M) and structural rearrangements (PGT-SR), a part of ART, has been presented together to minimize the fetal genetic risk and increase pregnancy rate. For patients or their families who are suffering from chromosome abnormality, monogenic disease, unexplained repeated spontaneous abortion or implantation failure, after accepting genetic counseling, they may be suggested to accept detection from more than one PGT platforms about the embryos to avoid some genetic diseases. However, PGT platforms work through different workflows. The high costliness, lack of material and long-time operation of combined PGT platforms limit their application. STUDY DESIGN, SIZE, DURATION: All 188 embryonic samples from 43 families were tested with HaploPGT platform, and most of their genetic abnormalities had been determined by different conventional PGT methods beforehand. Among them, there were 12 families only carrying structural rearrangements (115 embryos) in which 9 families accepted implantation and 5 families had normal labor ART outcomes, 7 families only carrying monogenic diseases (26 embryos) and 3 families carrying both structural rearrangements and monogenic diseases (26 embryos). Twelve monopronucleated zygotes (1PN) samples and 9 suspected triploid samples were collected from 21 families. PARTICIPANTS/MATERIALS, SETTINGS, METHODS: Here, we raised a comprehensive PGT method called HaploPGT, combining reduced representation genome sequencing, read-count analysis, B allele frequency and haplotyping analysis, to simultaneously detect different genetic disorders in one single test. MAIN RESULTS AND THE ROLE OF CHANCE: With 80 million reads (80M) genomic data, the proportion of windows (1 million base pairs (Mb)) containing two or more informative single nucleotide polymorphism (SNP) sites was 97.81%, meanwhile the genotyping error rate stabilized at a low level (2.19%). Furthermore, the informative SNPs were equally distributed across the genome, and whole-genomic haplotyping was established. Therefore, 80M was chosen to balance the cost and accuracy in HaploPGT. HaploPGT was able to identify abnormal embryos with triploid, global and partial loss of heterozygosity, and even to distinguish parental origin of copy number variation in mosaic and non-mosaic embryos. Besides, by retrospectively analyzing 188 embryonic samples from 43 families, HaploPGT revealed 100% concordance with the available results obtained from reference methods, including PGT-A, PGT-M, PGT-SR and PGT-HLA. LIMITATIONS, REASON FOR CAUTION: Despite the numerous benefits HaploPGT could bring, it still required additional family members to deduce the parental haplotype for identifying balanced translocation and monogenic mutation in tested embryos. In terms of PGT-SR, the additional family member could be a reference embryo with unbalanced translocation. For PGT-M, a proband was normally required. In both cases, genomic information from grandparents or parental siblings might help for haplotyping theoretically. Another restriction was that haploid, and diploid resulting from the duplication of a haploid, could not be told apart by HaploPGT, but it was able to recognize partial loss of heterozygosity in the embryonic genome. In addition, it should be noted that the location of rearrangement breakpoints and the situation of mutation sites were complicated, which meant that partial genetic disorders might not be completely detected. WIDER IMPLICATIONS OF THE FINDINGS: HaploPGT is an efficient and cost-effective detection platform with high clinical value for detecting genetic status. This platform could promote the application of PGT in ART, to increase pregnancy rate and decrease the birth of children with genetic diseases. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by grants from the National Natural Science Foundation of China (81873478, to L.H.), National Key R&D Program of China (2018YFC1003100, to L.H.), the Natural Science Foundation of Hunan Province (Grant 2022JJ30414, to P.X.), Hunan Provincial Grant for Innovative Province Construction (2019SK4012) and the Scientific Research Foundation of Reproductive and Genetic Hospital of China International Trust & Investment Corporation (CITIC)-Xiangya (YNXM-201910). Haplotyping analysis has been licensed to Basecare Co., Ltd. L.K., Y.M., K.K., D.Z., N.L., J.Z. and R.D. are Basecare Co., Ltd employees. The other authors declare no competing interests. TRIAL REGISTRATION NUMBER: N/A.

BasePhasing: a highly efficient approach for preimplantation genetic haplotyping in clinical application of balanced translocation carriers.

BACKGROUND: Preimplantation genetic testing (PGT) has already been applied in chromosomally balanced translocation carriers to improve the clinical outcome of assisted reproduction. However, traditional methods could not further distinguish embryos carrying a translocation from those with a normal karyotype prior to implantation. METHODS: To solve this problem, we developed a method named "Chromosomal Phasing on Base level" (BasePhasing), which based on Infinium Asian Screening Array-24 v1.0 (ASA) and a specially phasing pipeline. Firstly, by comparing the number of single nucleotide polymorphism (SNP) loci in different minor allele frequencies (MAFs) and in 2Mbp continuous windows of ASA chip and karyomap-12 chip, we verified whether ASA could be adopted for genome-wide haplotype linkage analysis. Besides, the whole gene amplification (WGA) of 3-10 cells of GM16457 cell line was used to verify whether ASA chip could be used for testing of WGA products. Finally, two balanced translocation families were utilized to carry out BasePhasing and to validate the feasibility of its clinical application. RESULTS: The average number of SNP loci in each window of ASA (473.2) was twice of that of Karyomap-12 (201.2). The coincidence rate of SNP loci in genomic DNA and WGA products was about 97%. The 5.3Mbp deletion was detected positively in cell line GM16457 of both genomic DNA and WGA products, and haplotype linkage analysis was performed in genome wide successfully. In the two balanced translocation families, 18 blastocysts were analyzed, in which 8 were unbalanced and the other 10 were balanced or normal chromosomes. Two embryos were transferred back to the patients successfully, and prenatal cytogenetic analysis of amniotic fluid was performed in the second trimester. The results predicted by BasePhasing and prenatal diagnosis were totally consistent. CONCLUSIONS: Infinium ASA bead chip based BasePhasing pipeline shows good performance in balanced translocation carrier testing. With the characteristics of simple operation procedure and accurate results, we demonstrate that BasePhasing is one of the most suitable methods to distinguish between balanced and structurally normal chromosome embryos from translocation carriers in PGT at present.

Diagnostic significance of urinary long non-coding PCA3 RNA in prostate cancer.

Prostate cancer antigen 3(PCA3) is a long non-coding RNA, which was found increased expression in CaP patients than healthy individual. In this study, the individual nucleic acid of PCA3 and PSA was recombinant expressed as a reference reagent, and a quantitative RT-PCR with TaqMan assay was developed to examine the copies of PCA3 and PSA gene in urine. The results showed that the area under the receiver operating characteristic curve (AUROC) was 0.717, 0.444 and 0.916 for the number of PCA3 copy, PSA copy and for the score of PCA3/PSA RNA, respectively. Additionally, the AUROC for serum tPSA was 0.674 with a low specificity of 12.07%. Finally, the algorithm of PCA3 RNA versus PSA RNA was evaluated and corroborated as CaP biomarker by conducting a multicentric clinical trial. This study not only validated the developed technique of qRT-PCR with TaqMan assay for examination of urinary PCA3 and PSA RNA, it also demonstrated that the score of the PCA/PSA RNA was a reliable signature for CaP diagnosis.

Molecular identification of one event of Ds excision and re-insertion at two loci in rice genome.

The maize Ac/Ds transposable elements are members of the hAT transposon superfamily, and have stable transpositional activity in transgenic rice plants. Ac/Ds transposable elements are considered to transpose via a conservative non-replicative "cut and paste" model, though their transposition mechanism is not completely understood. Previous studies have shown that Ds preferentially transposes to genetically linked sites after being excised from its original site in the presence of Ac-transposase. In this study, genomic sequences flanking Ds insertions from a Ds-tagged rice mutant and its rever- tant were determined by TAIL-PCR. The Ds insertion site, the excision footprint and the re-insertion sites in the mutant were identified using bioinformatics tool. The results showed that Ds element excised from its original insertion site on chromosome 3 by leaving an 8 bp footprint (CATCATGA), which resulted in exon changes in tagged gene. After the excision, Ds element was re-inserted into the coding sequences of two genes on chromosome 2 and chromosome 6, which encode a nicotianamine aminotransferase and a senescence-associated protein, respectively. The transposition behavior of Ds element in this study could not be fully explained by the "cut and paste" mechanism, while it is likely to transpose in a "cut and copy and paste" way.