NR5A1 is the key regulator of adrenal and gonadal development in both humans and mice. Recently, a missense substitution in human NR5A1, p.R92W, was shown to underlie gonadal dysgenesis in genetic males and testicular formation in genetic females. Here, we investigated the phenotypic effects of the p.R92W mutation on murine development. Mice carrying the p.R92W mutation manifested a similar but milder phenotype than that of the previously described Nr5a1 knockout mice. Importantly, mutation-positive XX mice showed no signs of masculinization. These results, together with prior observations, indicate that the p.R92W mutation in NR5A1/Nr5a1 encodes unique molecules that disrupt male gonadal development in both humans and mice and induces testicular formation specifically in human females. Our findings provide novel insights into the conservation and divergence in the molecular networks underlying mammalian sexual development.

Background: Although Y chromosomal genes are involved in male sex development, spermatogenesis, and height growth, these genes play no role in the survival or mitosis of somatic cells. Therefore, somatic cells lacking the Y chromosome can stay and proliferate in the body.Methods: Several molecular technologies, including next‐generation sequencing and multiplex PCR‐based assays, are used to detect mosaic loss of the Y chromosome (mLOY) in the blood of men.Main findings: Accumulating evidence suggests that mLOY represents the most common acquired chromosomal alteration in humans, affecting >40% of men over 70 years of age. Advanced age, tobacco smoking, and some SNPs in cell cycle genes are known to increase the frequency of mLOY. The developmental process of mLOY in elderly men remains to be clarified, but it possibly reflects recurrent mitotic elimination of Y chromosomes or clonal expansion of 45,X cell lineages. In rare cases, mLOY also occurs in young men and fetuses. MLOY has been associated with early death, cancers, and other disorders in elderly men, infertility in reproductive‐aged men, and developmental defects in children.Conclusion: Y chromosomes in men can be lost at every life stage and Y chromosomal loss is associated with various health problems.

Isolated hypogonadotropic hypogonadism (IHH), combined pituitary hormone deficiency (CPHD), and septo-optic dysplasia (SOD) constitute a disease spectrum whose etiology remains largely unknown. This study aimed to clarify whether mutations in SMCHD1, an epigenetic regulator gene, might underlie this disease spectrum. SMCHD1 is a causative gene for Bosma arhinia microphthalmia syndrome characterized by arhinia, microphthalmia and IHH. We performed mutation screening of SMCHD1 in patients with etiology-unknown IHH (n = 31) or CPHD (n = 43, 19 of whom also satisfied the SOD diagnostic criteria). Rare variants were subjected to in silico analyses and classified according to the American College of Medical Genetics and Genomics guidelines. Consequently, a rare likely pathogenic variant, p.Asp398Asn, was identified in one patient. The patient with p.Asp398Asn exhibited CPHD, optic nerve hypoplasia, and a thin retinal nerve fiber layer, and therefore satisfied the criteria of SOD. This patient showed a relatively low DNA methylation level of the 52 SMCHD1-target CpG sites at the D4Z4 locus. Exome sequencing for the patient excluded additional variants in other IHH/CPHD-causative genes. In vitro assays suggested functional impairment of the p.Asp398Asn variant. These results provide the first indication that SMCHD1 mutations represent a rare genetic cause of the HH-related disease spectrum.

Superovulation is a method used to reduce the number of mice used per experiment by increasing the egg number. Conventionally, superovulation for obtaining mouse eggs involves the use of equine chorionic gonadotropin (eCG) for stimulation and human CG for induction. Female mice of the C57BL/6 inbred strain spontaneously ovulate approximately 10 eggs. The average number of eggs ovulated using the conventional superovulation method is approximately twice as high as that obtained by spontaneous ovulation. Here, we describe the conventional and non-conventional methods of intraperitoneal injection of superovulation reagents in mice and subsequent egg collection. The non-conventional superovulation method combining anti-inhibin serum (AIS) plus eCG for stimulation is more efficient than conventional superovulation. Appropriate intervals from each injection to sampling induce large numbers of high-quality eggs. Immediately after ovulation, eggs are surrounded by cumulus cells, forming an egg-cumulus complex. These cumulus cells are then removed from the egg-cumulus complex by treatment with hyaluronidase to obtain the exact number of eggs. This protocol is suitable for further manipulations such as intracytoplasmic sperm injection and cryopreservation of eggs, as well as for the analyses of responsivity to superovulation reagents in genetically modified mice obtained by genome editing.