OBJECTIVE: To compare aneuploidy rates among in vitro fertilization (IVF) cycles using preimplantation genetic testing for monogenic disorders (PGT-M) and aneuploidy (PGT-A) compared with IVF cycles using PGT-A alone, and to determine the likelihood of obtaining at least one usable embryo in cycles using PGT-M+PGT-A compared with cycles using PGT-A alone.
METHODS: Retrospective cohort study.
METHODS: Single genetics laboratory.
METHODS: All IVF cycles for patients aged 18-45 undergoing PGT-A with or without concurrent PGT-M at a single genetics laboratory from November 2019 to March 2023.
METHODS: Use of PGT-M+PGT-A vs. use of PGT-A alone.
METHODS: Per cycle aneuploidy rate stratified by age, and per cycle likelihood of obtaining at least one usable embryo stratified by age and inheritance pattern of monogenic disease.
RESULTS: A total of 72,522 IVF cycles were included; 4,255 cycles (5.9%) using PGT-M+PGT-A and 68,267 cycles (94.1%) using PGT-A alone. The PGT-M+PGT-A group was younger than the PGT-A alone group (<35 years old: 56.1% vs. 30.5%). The majority of PGT-M cycles were performed for autosomal dominant pathogenic variants (42.4%), followed by autosomal recessive (36.5%), X-linked dominant (13.3%), and X-linked recessive (7.5%). The median number of embryos biopsied was higher in PGT-A alone compared with PGT-M+PGT-A cycles for patients aged <35, but it was equivalent in all other age groups. Age stratified aneuploidy rates did not significantly differ between PGT-M+PGT-A compared with PGT-A alone cycles. The probability of having a usable embryo declined with increasing age across all inheritance patterns. Compared with PGT-A alone, PGT-M+PGT-A cycles for patients aged ≤40 across all inheritance patterns were significantly less likely to yield a usable embryo, except in cycles for autosomal recessive diseases in the 38-40 age group and X-linked recessive diseases in the 35-37 age group. There were no consistent differences seen between groups in patients over 40. Cycles for patients with autosomal dominant diseases had the lowest likelihood of yielding a usable embryo for patients aged <43.
CONCLUSIONS: In vitro fertilization cycles using PGT-M+PGT-A have similar age-specific aneuploidy rates to those using PGT-A alone. Cycles for patients ≤40 using PGT-M+PGT-A are significantly less likely to yield a usable embryo compared with those using PGT-A alone.

Cystic fibrosis is a highly prevalent genetic disorder caused by biallelic pathogenic variants in the CFTR gene, causing an altered function of the exocrine glands and a subsequent spectrum of hypofunctional and degenerative manifestations. The increasing availability of carrier screening programmes, the enhanced life expectancy of patients due to improved treatment and care strategies and the development of more precise and affordable molecular diagnostic tools have prompted a rise in demand of prenatal diagnosis procedures for at-risk couples, including Preimplantation Genetic Testing (PGT). However, challenges remain: heterogeneity among screening programmes, nuances of variant interpretation and availability of novel treatments demand a considerate and knowledgeable approach to genetic counselling. In this work, we retrospectively evaluated the molecular data of 92 unselected couples who received a diagnosis of CFTR-related status and were referred to the genetics clinic at the University Hospital of Padua for genetic counselling on eligibility for PGT. A total of 50 couples were considered eligible for the procedure based on risk of transmitting biallelic pathogenic variants. We report and discuss our experience with this case series in the context of the Italian medical care system and present an overview of the most relevant issues regarding genetic counselling for PGT in CFTR-related disorders.

BACKGROUND: Ornithine carbamoyltransferase deficiency (OTCD) is a kind of X-linked metabolic disease caused by a deficiency in ornithine transcarbamylase leading to urea cycle disorders. The main reason is that the OTC gene variants lead to the loss or decrease of OTC enzyme function, which hinders the ammonia conversion to urea, resulting in hyperammonemia and severe neurological dysfunction. Here, we studied one Chinese family of three generations who consecutively gave birth to two babies with OTCD. This study aims to explore the pathogenicity of two missense variants in the OTC gene and investigate the application of preimplantation genetic testing for monogenic (PGT-M) for a family troubled by Ornithine carbamoyltransferase deficiency (OTCD).
METHODS: The retrospective method was used to classify the pathogenicity of two missense variants in the OTC gene in a family tortured by OTCD. Sanger sequencing was used to validate the variants in the OTC gene, and then the pathogenicity of variants was confirmed through family analysis and bioinformatics software. We used PGT-M to target the OTC gene and select a suitable embryo for transplantation. Prenatal diagnosis was recommended to confirm previous results using Sanger sequencing and karyotyping at an appropriate gestational stage. Tandem mass spectrometry (MS-MS) and gas chromatography-mass spectrometry (GC-MS) were used to detect fetal metabolism after birth. The number of the study cohort is ChiCTR2100053616.
RESULTS: Two missense variants, c.959G > C (p.Arg320Pro) and c.634G > A (p.Gly212Arg), were validated in the OTC gene in this family. According to the ACMG genetic variation classification criteria, the missense variant c.959G > C can be considered as \"pathogenic\", and the missense variant c.634G > A can be regarded as \"likely benign.\" PGT-M identified a female embryo carrying the heterozygous variant c.959G > C (p.Arg320Pro), which was selected for transplantation. Prenatal diagnosis revealed the same variant in the fetus, and continued pregnancy was recommended. A female baby was born, and her blood amino acid testing and urine organic acid testing were regular. Follow-up was conducted after six months and indicated the girl was healthy.
CONCLUSIONS: Our research first validated the segregation of both c.959G > C and c.634G > A variants in the OTC gene in a Chinese OTCD family. Then, we classified variant c.959G > C as \"pathogenic\" and variant c.634G > A as \"likely benign\", providing corresponding theoretical support for genetic counseling and fertility guidance in this family. PGT-M and prenatal diagnosis were recommended to help the couple receive a female baby successfully with a six-month follow-up.

Preimplantation genetic testing (PGT) is a diagnostic procedure that has become a powerful complement to assisted reproduction techniques. PGT has numerous indications, and there is a wide range of techniques that can be used, each with advantages and limitations that should be considered before choosing the more adequate one. In this article, it is reviewed the indications for PGT, biopsy and diagnostic technologies, along with their evolution, while also broaching new emerging methods.

BACKGROUND: GATA1-related cytopenia (GRC) is characterized by thrombocytopaenia and/or anaemia ranging from mild to severe. Haematopoietic stem cell transplantation (HSCT) is a healing therapeutic choice for GRC patients. We identified a novel pathogenic variant (GATA1: c.1019delG) in a boy with GATA1-related cytopenia. Then we performed preimplantation genetic testing (PGT) in this GRC family. After a mosaic embryo transfered, a healthy and HLA-compatible with the proband baby was delivered.
METHODS: The proband is a 6-year-old boy who was diagnosed to have transfusion-dependent anaemia since 3 year old. Whole-exome sequencing (WES) showed that the proband has a hemizygous variant c.1019delG in GATA1, which is inherited from his mother. His parents decided to undergo PGT to have a health and HLA-compatible offspring. After whole genome amplification (WGA) of biopsied trophectoderm (TE) cells, next generation sequencing (NGS)-based PGT was preformed to analyse embryos on chromosomal aneuploidy, target mutation and HLA typing. There were 3 embryos HLA-matched to the proband. The genotypes of the 3 embryos were heterozygous variant, hemizygous variant, normal respectively. After a heterozygous, mosaic partial trisomy (chr)16, and HLA-matched embryo transfer, a healthy baby was delivered and whose HSCT is compatible with the proband.
CONCLUSIONS: NGS-based PGT-HLA is a valuable procedure for the treatment of GATA1-related cytopenia caused by GATA1 variants, or other haematological disorders, oncological and immunological diseases. Furthermore, our study reconfirms that mosaic embryos transfer would bring healthy offspring.

Preimplantation genetic testing for monogenic diseases for adult-onset conditions is ethically permissible for various conditions, including when the condition is fully penetrant or confers disease predisposition. The Committee strongly recommends that a genetic counselor experienced with both preimplantation genetic testing for monogenic diseases and assisted reproductive technology therapies counsel patients considering such procedures.

OBJECTIVE: To showcase the successful use of ICSI with PGT-M to overcome Beckwith-Wiedemann syndrome (BWS)-related reproductive challenges, resulting in the birth of a healthy baby boy. By targeting the maternally inherited CDKN1C pathogenic gene variant, this report highlights the genetic interventions in BWS reproductive risk management.
METHODS: This case report describes a 41-year-old woman seeking fertility assistance after a previous pregnancy revealed a fetal anomaly related to BWS. Families with BWS recurrence face challenges, as maternally inherited CDKN1C pathogenic variants contribute to approximately 40% of genetic alterations, with a potential recurrence risk as high as 50%. Genetic analysis identified a pathogenic variant in the CDKN1C gene of the fetus that was maternally inherited. The pregnancy was terminated due to the fetal anomalies. The couple underwent intra-cytoplasmic sperm injection (ICSI) combined with preimplantation genetic testing for monogenic diseases (PGT-M) and preimplantation genetic testing for aneuploidy (PGT-A).
RESULTS: Two embryos from IVF with low-risk PGT-M and euploid status. One transferred via frozen embryo transfer (FET) in February 2023 resulted in the successful birth of a healthy baby boy. This study reports the first successful delivery of a healthy boy after PGT-M for the CDKN1C gene variant c.79_100delinsGTGACC, contributing to the limited literature on successful outcomes for BWS.
CONCLUSIONS: Utilizing PGT-M in combination with IVF can lead to favorable outcomes in managing BWS-associated reproductive challenges, offering insights into potential genetic interventions and successful birth.

UNASSIGNED: Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a rare autosomal dominant inheritable disease caused by Fumarate hydratase (FH) gene germline mutation. It is speculated that for HRLCC infertility women with multiple uterine leiomyomas, preimplantation genetic testing may help block transmission of mutated FH gene during pregnancy.
UNASSIGNED: We present the case of a 26-year-old nulligravida with a history of early-onset uterine leiomyomatosis had a heterozygous nonsense mutation [NM_000143.4 (FH): c.1027C > T(p.Arg343Ter)] in the HRLLC gene. After ovulation induction and in vitro fertilization, preimplantation genetic testing for monogenic disorders (PGT-M) on embryos revealed the absence of the pathogenic allele in two blastomeres. Uterine fibroids were identified before embryo transfer, leading to a submucosal myomectomy and long period of pituitary suppression by Gonadotropin-releasing hormone analog (GnRHa). The patient achieved a healthy live birth after the second cycle of frozen-thawed embryo transfer.
UNASSIGNED: This case details the successful treatment of an infertile patient with an HRLLC family history, resulting in a healthy birth through myomectomy and PGT-M selected embryo transplantation. Our literature search indicates the first reported live birth after HRLLC-PGT-M.

Ganglioside-monosialic acid (GM1) gangliosidosis (ICD-10: E75.1; OMIM: 230500, 230600, 230650) is a rare autosomal recessive hereditary disease, lysosomal storage disorder caused by mutations in the GLB1 gene that lead to the absence or insufficiency of β-galactosidase. In this study, we report a case of a Russian family with a history of GM1 gangliosidosis. The family had a child who, from the age of 6 months, experienced a gradual loss of developmental skills, marked by muscle flaccidity, psychomotor retardation, hepatosplenomegaly, and the onset of tonic seizures by the age of 8 months. Funduscopic examination revealed a «cherry red spot» in the macula, which is crucial for the diagnosis of lipid storage disorders. To find the pathogenic variants responsible for these clinical symptoms, the next-generation sequencing approach was used. The analysis revealed two variants in the heterozygous state: a frameshift variant c.699delG (rs1452318343, ClinVar ID 928700) in exon 6 and a missense variant c.809A>C (rs371546950, ClinVar ID 198727) in exon 8 of the GLB1 gene. The spouses were advised to plan the pregnancy with assisted reproductive technology (ART), followed by preimplantation genetic testing for monogenic disorder (PGT-M) on the embryos. Trophectoderm biopsy was performed on 8 out of 10 resulting embryos at the blastocyst stage. To perform PGT-M, we developed a novel testing system, allowing for direct analysis of disease-causing mutations, as well as haplotype analysis based on the study of polymorphic markers-short tandem repeats (STR), located upstream and downstream of the GLB1 gene. The results showed that four embryos were heterozygous carriers of pathogenic variants in the GLB1 gene (#1, 2, 5, 8). Two embryos had a compound heterozygous genotype (#3, 4), while the embryos #7 and 9 did not carry disease-causing alleles of the GLB1 gene. The embryo #7 without pathogenic variants was transferred after consideration of its morphology and growth rate. Prenatal diagnosis in the first trimester showed the absence of the variants analyzed in the GLB1 gene in the fetus. The pregnancy resulted in the delivery of a female infant who did not inherit the disease-causing variants in the GLB1 gene.

Pre-implantation genetic testing (PGT) is a vital tool in preventing chromosomal aneuploidies and other genetic disorders including those that are monogenic in origin. It is performed on embryos created by intracytoplasmic sperm injection (ICSI). Genetic counseling in the area of assisted reproductive technology (ART) has also evolved along with PGT and is considered an essential and integral part of Reproductive Medicine. While PGT has the potential to prevent future progeny from being affected by genetic conditions, genetic counseling helps couples understand and adapt to the medical, psychological, familial and social implications of the genetic contribution to disease. Genetic counseling is particularly helpful for couples with recurrent miscarriages, advanced maternal age, a partner with a chromosome translocation or inversion, those in a consanguineous marriage, and those using donor gametes. Partners with a family history of genetic conditions including hereditary cancer, late onset neurological diseases and with a carrier status for monogenic disorders can benefit from genetic counseling when undergoing PGT for monogenic disorders (PGT-M). Genetic counseling for PGT is useful in cases of Mendelian disorders, autosomal dominant and recessive conditions and sex chromosome linked disorders and for the purposes of utilizing HLA matching technology for creating a savior sibling. It also helps in understanding the importance of PGT in cases of variants of uncertain significance (VUS) and variable penetrance. The possibilities and limitations are discussed in detail during the sessions of genetic counseling.