Clinical utility of combined preimplantation genetic testing methods in couples at risk of passing on beta thalassemia/hemoglobin E disease: A retrospective review from a single center

The frontier of precision medicine: application of single-cell multi-omics in preimplantation genetic diagnosis

The advent of single-cell multi-omics technologies has revolutionized the landscape of preimplantation genetic diagnosis (PGD), offering unprecedented insights into the genetic, transcriptomic, and proteomic profiles of individual cells in early-stage embryos. This breakthrough holds the promise of enhancing the accuracy, efficiency, and scope of PGD, thereby significantly improving outcomes in assisted reproductive technologies (ARTs) and genetic disease prevention. This review provides a comprehensive overview of the importance of PGD in the context of precision medicine and elucidates how single-cell multi-omics technologies have transformed this field. We begin with a brief history of PGD, highlighting its evolution and application in detecting genetic disorders and facilitating ART. Subsequently, we delve into the principles, methodologies, and applications of single-cell genomics, transcriptomics, and proteomics in PGD, emphasizing their role in improving diagnostic precision and efficiency. Furthermore, we review significant recent advances within this domain, including key experimental designs, findings, and their implications for PGD practices. The advantages and limitations of these studies are analyzed to assess their potential impact on the future development of PGD technologies. Looking forward, we discuss the emerging research directions and challenges, focusing on technological advancements, new application areas, and strategies to overcome existing limitations. In conclusion, this review underscores the pivotal role of single-cell multi-omics in PGD, highlighting its potential to drive the progress of precision medicine and personalized treatment strategies, thereby marking a new era in reproductive genetics and healthcare.

Clinical outcomes following preimplantation genetic testing for monogenic conditions: a systematic review of observational studies

OBJECTIVE

We aimed to report a summary of clinical outcomes following preimplantation genetic testing for monogenic conditions, by performing a systematic review of published literature on clinical pregnancy and live birth rates following preimplantation genetic testing due to a monogenic indication. Additionally, we aimed to undertake a subgroup analysis of clinical outcomes of concurrent monogenic and aneuploidy screening.

DATA SOURCES

Three electronic databases (MEDLINE, EMBASE, and PubMed) were searched from inception to May 2024.

STUDY ELIGIBILITY CRITERIA

Quantitative data audits, observational studies, and case series reporting clinical outcomes for individuals undergoing preimplantation genetic testing for a monogenic indication were included. Only studies using blastocyst biopsies with polymerase chain reaction-based or genome-wide haplotyping methods for molecular analysis were eligible to reflect current laboratory practice.

METHODS

Quality assessment was performed following data extraction using an adaptation of the Joanna Briggs critical appraisal tool for case series. Results were extracted, and pooled mean clinical pregnancy rates and birth rates were calculated with 95% confidence intervals (95% CI). We compared outcomes between those with and without concurrent preimplantation genetic testing for aneuploidy.

RESULTS

Our search identified 1372 publications; 51 were eligible for inclusion. Pooled data on 5305 cycles and 5229 embryo transfers yielded 1806 clinical pregnancies and 1577 births. This translated to clinical pregnancy and birth rates of 34.0% [95% CI: 32.8%-35.3%] and 29.7% [95% CI: 28.5%-31.0%] per cycle and 24.8% [95% CI: 23.6%-26.0%] and 21.7% [95% CI: 20.8%-23.1%] per embryo transfer. In studies with concurrent aneuploidy screening, clinical pregnancy and birth rates were 43.3% [95% CI: 40.2%-46.5%] and 37.6% [95% CI: 34.6%-40.8%] per cycle and 37.0% [95% CI: 33.9%-40.3%] and 31.8% [95% CI: 28.8%-35.0%] per embryo transfer. Studies without aneuploidy screening reported clinical pregnancy and birth rates of 32.5% [95% CI: 31.0%-34.1%] and 28.1% [95% CI: 26.6%-29.7%] per cycle and 21.2% [95% CI: 19.8%-22.6%] and 18.6% [95% CI: 17.3%-20.0%] per embryo transfer.

CONCLUSION

This systematic review reveals promising clinical outcome figures for this indication group. Additionally, synthesizing the published scientific literature on clinical outcomes from preimplantation genetic testing for monogenic conditions provides a rigorous, noncommercial evidence base for counseling.

The effect of red blood cell disorders on male fertility and reproductive health

Male infertility is defined as a failure to conceive after 12 months of unprotected intercourse owing to suspected male reproductive factors. Non-malignant red blood cell disorders are systemic conditions that have been associated with male infertility with varying severity and strength of evidence. Hereditary haemoglobinopathies and bone marrow failure syndromes have been associated with hypothalamic-pituitary-gonadal axis dysfunction, hypogonadism, and abnormal sperm parameters. Bone marrow transplantation is a potential cure for these conditions, but exposes patients to potentially gonadotoxic chemotherapy and/or radiation that could further impair fertility. Iron imbalance might also reduce male fertility. Thus, disorders of hereditary iron overload can cause iron deposition in tissues that might result in hypogonadism and impaired spermatogenesis, whereas severe iron deficiency can propagate anaemias that decrease gonadotropin release and sperm counts. Reproductive urologists should be included in the comprehensive care of patients with red blood cell disorders, especially when gonadotoxic treatments are being considered, to ensure fertility concerns are appropriately evaluated and managed.

Appropriate whole genome amplification and pathogenic loci detection can improve the accuracy of preimplantation genetic diagnosis for deletional α-thalassemia

Objective

To improve the accuracy of preimplantation genetic testing (PGT) in deletional α-thalassemia patients.

Design

Article.

Patients

fifty-two deletional α-thalassemia couples.

Interventions

Whole genome amplification (WGA), Next-generation sequencing (NGS) and PCR mutation loci detection.

Main outcome measures

WGA, Single nucleotide polymorphism (SNP) and PCR mutation loci detection results; Analysis of embryo chromosome copy number variation (CNV).

Results

Multiple Displacement Amplification (MDA) and Multiple Annealing and Looping-Based Amplification Cycles (MALBAC) methods for PGT for deletional α-thalassemia. Blastocyst biopsy samples (n = 253) were obtained from 52 deletional α-thalassemia couples. The results of the comparison of experimental data between groups MALBAC and MDA are as follows: (i) The average allele drop-out (ADO) rate, MALBAC vs. MDA = 2.27% ± 3.57% vs. 0.97% ± 1.4%, P=0.451); (ii) WGA success rate, MALBAC vs. MDA = 98.61% vs. 98.89%, P=0.851; (iii) SNP haplotype success rate, MALBAC vs. MDA = 94.44% vs. 96.68%, P=0.409; (iv) The result of SNP haplotype analysis is consistent with that of Gap-PCR/Sanger sequencing results, MALBAC vs. MDA = 36(36/72, 50%) vs. 151(151/181, 83.43%), P=0; (v) Valid SNP loci, MALBAC vs. MDA = 30 ± 9 vs. 34 ± 10, P=0.02; (vi) The mean CV values, MALBAC vs. MDA = 0.12 ± 0.263 vs. 0.09 ± 0.40, P=0.916; (vii) The average number of raw reads, MALBAC vs. MDA =3244259 ± 999124 vs. 3713146 ± 1028721, P=0; (viii) The coverage of genome (%), MALBAC vs. MDA = 5.02 ± 1.09 vs. 5.55 ± 1.49, P=0.008.

Conclusions

Our findings indicate that MDA is superior to MALBAC for PGT of deletional α-thalassemia. Furthermore, SNP haplotype analysis combined with PCR loci detection can improve the accuracy and detection rate of deletional α-thalassemia.

Integrative preimplantation genetic testing analysis for a Chinese family with hereditary spherocytosis caused by a novel splicing variant of SPTB

Hereditary spherocytosis (HS), the most common inherited hemolytic anemia disorder, is characterized by osmotically fragile microspherocytic red cells with a reduced surface area on the peripheral blood smear. Pathogenic variants in five erythrocyte membrane structure-related genes ANK1 (Spherocytosis, type 1; MIM#182900), SPTB (Spherocytosis, type 2; MIM#616649), SPTA1 (Spherocytosis, type 3; MIM#270970), SLC4A1 (Spherocytosis, type 4; MIM#612653) and EPB42 (Spherocytosis, type 5; MIM#612690) have been confirmed to be related to HS. There have been many studies on the pathogenic variants and mechanisms of HS, however, studies on how to manage the transmission of HS to the next-generation have not been reported. In this study, we recruited a patient with HS. Targeted next-generation sequencing with a panel of 208 genes related to blood system diseases detected a novel heterozygous variant in the SPTB: c.300+2dup in the proband. Sanger sequencing of variant alleles and haplotype linkage analysis of single nucleotide polymorphism (SNP) based on next-generation sequencing were performed simultaneously. Five embryos were identified with one heterozygous and four not carrying the SPTB variant. Single-cell amplification and whole genome sequencing showed that three embryos had varying degrees of trisomy mosaicism. One of two normal embryos was transferred to the proband. Ultimately, a healthy boy was born, confirmed by noninvasive prenatal testing for monogenic conditions (NIPT-M) to be disease-free. This confirmed our successful application of PGT in preventing transmission of the pathogenic variant allele in the HS family.

Hemoglobinopathies and preimplantation diagnostics

Hemoglobinopathies constitute some of the most common inherited disorders worldwide. Manifestations are very severe, patient management is difficult and treatment is not easily accessible. Preimplantation genetic testing for monogenic disorders (PGT-M) is a valuable reproductive option for hemoglobinopathy carrier-couples as it precludes the initiation of an affected pregnancy. PGT-M is performed on embryos generated by assisted reproductive technologies and only those found to be free of the monogenic disorder are transferred to the uterus. PGT-M has been applied for 30 years now and β-thalassemia is one of the most common indications. PGT may also be applied for human leukocyte antigen typing to identify embryos that are unaffected and also compatible with an affected sibling in need of hemopoietic stem cell transplantation. PGT-M protocols have evolved from PCR amplification-based, where a small number of loci were analysed, to whole genome amplification-based, the latter increasing diagnostic accuracy, enabling the development of more generic strategies and facilitating multiple diagnoses in one embryo. Currently, numerous PGT-M cycles are performed for the simultaneous diagnosis of hemoglobinopathies and screening for chromosomal abnormalities in the embryo in an attempt to further improve success rates and increase deliveries of unaffected babies.

Applications of next generation sequencing in the screening and diagnosis of thalassemia: A mini-review

Thalassemias are a group of inherited blood disorders that affects 5-7% of the world population. Comprehensive screening strategies are essential for the management and prevention of this disorder. Today, many clinical and research laboratories have widely utilized next-generation sequencing (NGS) technologies to identify diseases, from germline and somatic disorders to infectious diseases. Yet, NGS application in thalassemia is limited and has just recently surfaced due to current demands in seeking alternative DNA screening tools that are more efficient, versatile, and cost-effective. This review aims to understand the several aspects of NGS technology, including its most current and expanding uses, advantages, and limitations, along with the issues and solutions related to its integration into routine screening and diagnosis of thalassemias. Hitherto, NGS has been a groundbreaking technology that offers tremendous improvements as a diagnostic tool for thalassemia in terms of its higher throughput, accuracy, and adaptability. The superiority of NGS in detecting rare variants, solving complex hematological problems, and providing non-invasive alternatives to neonatal diagnosis cannot be overlooked. However, several pitfalls still preclude its use as a stand-alone technique over conventional methods.

The Prevalence of β-Thalassemia and Other Hemoglobinopathies in Kuwaiti Premarital Screening Program: An 11-Year Experience

This study aims to estimate the prevalence rates of β-thalassemia and Sickle cell disorders in the adult population screened (n = 275,819) as part of the Kuwaiti National Premarital Screening Program. All the individuals who applied for a marriage license during the years 2009 and 2020 were covered by the program. A network of four reception centers in the Ministry of Health facilities and one Premarital Diagnostic Laboratory (PDL) in Maternity Hospital were involved in performing all investigations for hemoglobinopathies. The total number of individuals identified with β-thal trait was 5861 (2.12%), while 22 individuals (0.008%) were diagnosed with β-thal disease. A total of 5003 subjects (1.81%) were carrying the Sickle cell trait, while 172 subjects (0.062%) had Sickle cell disease including Sickle cell anemia (SCA). Results showed that the program succeeded indeed in preventing the marriage of 50.4% of risky couples by issuing unsafe marriage certificates. Yet more efforts are needed to improve the program’s main objective of decreasing high-risk marriages. In particular, health care systems should be ameliorated in a way to intensify the counselling mechanism for the high-risk couples, strengthen the awareness of the general population and induce earlier age screening policies.

Cumulative outcome of pre-implantation genetic diagnosis for sickle cell disease: a 5-year review

To review the cumulative outcome of pre-implantation genetic diagnosis (PGD) cycles performed for prevention of sickle cell disease (SCD). Couples referred for PGD for SCD between April 2012 and October 2017 were included. Ovarian stimulation was performed using a short gonadotrophin-releasing hormone (GnRH) antagonist protocol and follicle-stimulating hormone injections. The GnRH agonist was used to trigger oocyte maturation. Oocytes were fertilised using intracytoplasmic sperm injection. Trophectoderm biopsy was performed on day 5 or 6 followed by vitrification. Genetic testing was done using pre-implantation genetic haplotyping. A total of 60 couples started 70 fresh PGD cycles (mean 1·2 cycles/couple) and underwent a total of 74 frozen-embryo-transfer (FET) cycles (mean 1·3 FET/couple). The mean (SD) female age was 33 (4·4) years and the mean (SD) anti-müllerian hormone level was 22·9 (2·8) pmol/l. The cumulative live-birth rate was 54%/PGD cycle started and 63%/couple embarking on PGD. The rate of multiple births was 8%. The cumulative outcome of PGD treatment for prevention of SCD transmission is high and PGD treatment should be offered to all at-risk couples.

Hemoglobinopathy E in 4 siblings of a North Indian family: A hidden malaise of social problem

The preference for male child and neglect of girl child for long has resulted in a hazardously poor sex ratio, but bride buying seems to be no solution for it as it has its own inherent consequences on society and public health. This article tries to look at a relationship between a state's poorly kept secret like bride buying and its unseen complications. Here, we report a family of six members, where all 4 children have hemoglobin E disease a relatively rare entity seen in this part of the country. Hemoglobin E (β26 Glu → Lys) is usually seen in northeastern parts of India. This case report has tried to highlight a relatively rare disease afflicting all children of the family due to gene mutations which are rarely seen in Haryana/Punjab.