Dados do Trabalho

Title

Live births following sperm selection based on the hypo-osmotic swelling test and preimplantation genetic testing from chromosomal translocation carriers: a report of two cases

Objective

The aim of this case report is to demonstrate that the hypo-osmotic swelling test (HOST) could potentially be used to select genetically balanced spermatozoa in male chromosomal rearrangement carriers, and along with the preimplantation genetic testing (PGT) improve the live birth rates for patients undergoing in vitro fertilization (IVF) treatment.

Methods

Even though HOST is an obsolete test to assess sperm vitality, according to recent studies, a specific HOST class, B+ type spermatozoa, showed a drastically lower proportion of chromosomally unbalanced cells compared to unselected spermatozoa. For each case here presented, we performed an IVF cycle with standard ovarian stimulation and oocyte retrieval. Semen samples of the translocation carrier patients were subjected to density gradient centrifugation followed by incubation in a hypo-osmotic solution. After HOST-morphology sperm sorting, intracytoplasmic sperm injection (ICSI) was performed. The details of each case are following presented.

Case 1: a 39-year-old man carrying a double translocation, both t(4;16)(q28;q21) reciprocal translocation and der(13;14)(q10;q10) Robertsonian translocation, and his partner, a 36-year-old woman. It was retrieved 19 cumulus-oocyte complexes, of which 14 metaphase II oocytes were fertilized by ICSI; embryo biopsy was performed on three blastocysts on day 5 and on two blastocysts on day 6; only one day 5 blastocyst (B5AA) was found to be euploid and chromosomally balanced according to PGT.

Case 2: a 37-year-old man carrying a reciprocal translocation t(11:18)(q21;q22) and his partner, a 32-year-old woman. In their case, 14 cumulus-oocyte complexes were retrieved, of which 9 metaphase II oocytes were fertilized by ICSI; five blastocysts were biopsied on day 5; according to PGT, only one blastocyst (B4AB) was found to be euploid and chromosomally balanced.

Results

In both cases, the euploid and chromosomally balanced blastocysts were transferred and resulted in successful pregnancies and births. The live births remain healthy and in normal development to date. Below are a few highlights of each case outcome.

Case 1: the only complication during pregnancy was subchorionic hematoma at 6 weeks, but with no high repercussions. In November 2022, a healthy female baby was delivered at the gestational age of 39 weeks.

Case 2: the repercussions during pregnancy were gestational diabetes and postpartum hemorrhage. In July 2022, a healthy male baby was delivered at the gestational age of 38 weeks.

Conclusion

This report demonstrates that HOST is a potential sperm selection method for patients with chromosomal rearrangements. Most remarkably, as far as we know, this is the first report of live births after using the combined technique of HOST-selection and PGT for chromosomal rearrangement carriers, especially in the rare case of the double chromosomal translocation carrier.

Keywords

Chromosomal rearrangement; Chromosomal translocation; Hypo-osmotic swelling test; Sperm selection.