ART strategies in Klinefelter syndrome

Abstract

Purpose: Patients with Klinefelter syndrome (KS) who receive assisted reproductive technology (ART) treatment often experience poor pregnancy rates due to decreased fertilization, cleavage, and implantation rates and even an increased miscarriage rate. Mounting evidence from recent studies has shown that various technological advances and approaches could facilitate the success of ART treatment for KS patients. In this review, we summarize the methods for guiding KS patients during ART and for developing optimal strategies for preserving fertility, improving pregnancy rate and live birth rate, and avoiding the birth of KS infants.

Methods: We searched PubMed and Google Scholar publications related to KS patients on topics of controlled ovarian stimulation protocols, sperm extraction, fertility preservation, gamete artificial activation, round spermatid injection (ROSI), and non-invasive prenatal screening (PGD) methods.

Results: This review outlines the different ovulation-inducing treatments for female partners according to the individual sperm status in the KS patient. We further summarize the methods of retrieving sperm, storing, and freezing rare sperm. We reviewed different methods of gamete artificial activation and discussed the feasibility of ROSI for sterile KS patients who absolutely lack sperm. The activation of eggs in the process of intracytoplasmic sperm injection and non-invasive PGD are urgently needed to prevent the birth of KS infants.

Conclusion: The integrated strategies will pave the way for the establishment of ART treatment approaches and improve the clinical outcome for KS patients.

Keywords: Administration strategy; Fertility preservation; Klinefelter syndrome; Single sperm cryopreservation; TESE.

Fig. 1

Flow chart for cryopreserving the sperm from KS patients. Adolescent or pre-pubertal KS patients need a professional medical consultation. If sperm is found in their masturbation semen, cryopreservation should be performed as soon as possible. For adult KS patients, regardless of the use of fresh semen or surgically obtained spermatozoa, if the concentration is beyond 0.1 × 10⁶/ml, a straw tube is suitable for stocking this kind of spermatozoan; for 10/ml to 0.1 × 10⁶/ml, an LSL tube; for less than 10/ml, the cryopiece system; and for less than 10/ml or less than 5-10 sperm cells, elongated spermatids, or round spermatid cells, the umSSC system is the optimal choice for cryopreservation

Fig. 2

Schematic illustration of the single sperm cryopreservative system. (A) Droplets, polypropylene carrier and ZC (Z.Z and C.W designed the device, named it ZC box) box of a single sperm cryopreservative system. (B) The cryoprotectant was loaded onto the polypropylene carrier. (C) The polypropylene carrier with cryoprotectant was placed into the bottom of the dish, and the cryoprotectant was then divided into a 0.01 μl micro-drop. The prepared extremely rare spermatozoa sample from ejaculated sperm, TESE or thawing sperm was loaded on the dish and then covered with mineral oil. (D) The motile spermatozoa were captured and loaded on the microdrops by ICSI pipettes, following storage in the liquid nitrogen tank and recorded for each sperm’s information. (E) The polypropylene carrier with spermatozoa was inserted into the bottom of a dish and covered with warm mineral oil for thawing, and the recovered spermatozoa were prepared for ICSI

Fig. 3

The flow chart for selection and assisted activation of the available spermatozoa from KS patients. The motile sperm from ejaculated sperm, TESE or thawing sperm was directly used for ICSI. If no motility was found, the immotile sperm was loaded onto the lanes as indicated in the figure and then selected by a mechanical technique, LAISS or HOS test. If the terato-sperm was chosen for ICSI or the immotile sperm underwent HOS or laser treatment, artificial ovarian activation is recommended

Fig. 4

Schematic illustration of the integrated administration strategies in KS patients’ ART treatment. For spouses of KS patients, the selection of the COS protocol should be determined according to the status of sperm retrieved from KS patients in order to obtain an appropriate number of mature eggs and minimize the risk of OHSS. We recommend choosing a GnRH agonist long protocol if sperm concentration > 0.1 × 10⁶/ml, a GnRH antagonist protocol if sperm concentration < 0.1 × 10⁶/ml but >10 cells, and a GnRH agonist short protocol or mild stimulation protocol if sperm<10 cells. For KS patients who are confirmed to have no sperm after microsurgery, the COS protocol of their spouses should be determined individually on the basis of age, BMI and ovarian reserve. The obtained MII eggs are subsequently used for ICSI or ROSI. If no spermatozoa are found, the cycle should be cancelled and the eggs frozen until sperm is available. Artificial insemination by donor (AID) or IVF by donor semen will be selected according to the tubal patency test of the spouses of KS patients who eventually have no sperm. Regarding KS patients, except for those with ejaculated sperm, the remainder of azoospermia KS patients should be re-evaluated after a short period of medication treatment. Patients who still present azoospermia after medication should undergo surgery, such as TESA, c-TESE or micro-TESE, for sperm extraction. Then, different methods are selected for sperm cryopreservation according to the number and morphology of the retrieved sperm. For extremely rare sperm, a single sperm cryopreservation system is preferred. Subsequently, ICSI is performed after activating immotile sperm in combination with a variety of methods, and ROSI is performed in patients with only round spermatids. Oocyte activation should be considered for all KS patients to increase the fertility rate. In addition, non-invasive PGD and strict prenatal diagnosis are helpful to avoid the transfer of 47, XXY genotype embryos and the birth of children with KS.