First Report on Ovarian Tissue Cryopreservation for A 6-Year-Old Girl with Non-Mosaic Turner Syndrome (45, X) in Japan: A Case Report.

A six-year-old girl was diagnosed with Turner syndrome (TS), monosomy X, based on results of amniotic fluid and leukocyte karyotyping. It is well known that most patients with TS are infertile due to premature ovarian insufficiency before puberty. The patient and her parents desired fertility preservation (FP) through ovarian tissue cryopreservation (OTC), which is the only option for FP in prepubertal patients, to prepare for future loss of fertility. OTC was performed after the physician provided sufficient information to the patient, and informed consent and assent were obtained. The girl's right ovary was removed in a Shiga University of Medical Science hospital and her father transported it for about 3.5 hours to a cryopreservation facility, HOPE in Tokyo. The removed ovary, measuring 3.0 cm × 1.2 cm and weighing 0.96 g, appeared striated. It was divided into 4 pieces and cryopreserved by slow freezing method. Pathology specimen examination showed no primordial follicles, but calcein-AM staining performed prior to cryopreservation detected 6 viable follicles. This report is valuable as we succeeded in cryopreserving autologous gametes in non-mosaic TS patients using calcein-AM staining, which made it possible to detect follicles with certainty in all samples. Although there has been insufficient evidence regarding the subjects and efficacies of FP for genetic and chromosomal disorders, earlier FP should be considered because individuals may lose their fertility prematurely. OTC may be a promising option to preserve fertility for girls with TS as well as childhood cancer patients.