P-548 IMPORTANCE OF EXPANDED CARRIER SCREENING AMONG OOCYTE DONORS - questions and concerns

Study question

To examine the utility of a range of expanded screening panels for oocyte donors.

Summary answer

Expanded carrier screening with NGS data identified that 86% of gamete donors were carriers of at least one condition while 302 genes were tested.

What is known already

The level of genetic testing for oocyte donors is not regulated in most countries. The use of expanded carrier screening is recommended more widely. If the egg donor is a carrier, there is a 50% chance that the offspring will also be carriers. Expanded carrier screening is performed to determine the potential effects of positive carrier status, which guarantees safety for future pregnancy. From practical experience, more genes are tested for a donor, more potential mutations are detected.

Study design, size, duration

A cohort of 92 potential oocyte donor applicants aged 18-30 years old, who were qualified for oocyte donation after full screening, tested negative on an initial cystic fibrosis carrier test for 11 most common CFTR mutations (PCR panel), was further screened with expanded commercial carrier testing panel (302 genes) using next-generation sequencing (NGS) data.

Participants/materials, setting, methods

A cohort of 92 potential oocyte donor applicants aged 18-30 years old, who tested negative on an initial cystic fibrosis carrier test for 11 most common CFTR mutations (PCR panel), was further screened with expanded commercial carrier testing panel (302 genes) using next-generation sequencing (NGS) data.

Main results and the role of chance

Genotyping results for all donors were analyzed; 38% (35/92) of donors were identified as carriers for one condition, 34% (31/92)- for two conditions, 7% (6/92)- for three conditions and 7% (6/92)- for four conditions, including cystic fibrosis. Among the most prevalent conditions in our study were: Hemochromatosis: Type 1: HFE Related- 22%, Cystic Fibrosis: CFTR-related conditions 11%, Biotinidase deficiency– 7,6%, 21-Hydroxilase-Deficient Congenital Nonclassical Adrenal Hyperplasia- 6,5%, Krabbe disease – 6,5%, Usher syndrome: USH2A-related conditions – 6,5%, Nonsyndromic deafness: GJB2- related conditions- 5,4% and Smith-Lemli-Opitz syndrome (5,4%).

Limitations, reasons for caution

Each donor was consented for genetic testing

Wider implications of the findings

This study shows a need to provide the explicit requirement for oocyte donor genetic testing and guidelines to satisfy quality and safety and not reduce the number of donors carries of mutations, but to implement a practice of genetic matching.

Trial registration number

not applicable

Effects of tris(1-chloro-2-propyl)phosphate and tris(2-chloroethyl)phosphate on cell viability and morphological changes in peripheral blood mononuclear cells (in vitro study)

Organophosphorus flame retardants (OPFRs) are a group of chemicals widely used in various everyday use products. Tris(2-chloroethyl)phosphate (TCEP) and tris(1-chloro-2-propyl)phosphate (TCPP) are one of the commonly used chemicals belonging to this group. Due to the need of limitation of the use of polybrominated diphenyl ethers (PBDEs) as retardants, the share of the compounds tested in our experiments in chemicals production systematically increases. There is limited information about the influence of halogenated OPFRs on living cells, especially on the immune system cells. That is why the aim of this study was to assess the impact of TCEP and TCPP on viability and morphological alterations of human peripheral blood mononuclear cells (PBMCs). The cells were incubated with selected flame retardants in the concentrations ranging from 0.001 to 1 mM for 24 h. It was found that TCEP at 1 mM and TCPP at 0.5 mM decreased viability of PBMCs, while only TCPP induced morphological alterations in the incubated cells. The results of our experiments suggest that TCPP is more cytotoxic than TCEP, which can be explained by the presence of methyl groups in the molecule of this compound. Similar to other studies, our data also suggest that OPFRs are suitable replacements for PBDEs.