Generation of functional oocytes from male mice in vitro

Sex chromosome disorders severely compromise gametogenesis in both males and females. In oogenesis, the presence of an additional Y chromosome or the loss of an X chromosome disturbs the robust production of oocytes1-5. Here we efficiently converted the XY chromosome set to XX without an additional Y chromosome in mouse pluripotent stem (PS) cells. In addition, this chromosomal alteration successfully eradicated trisomy 16, a model of Down's syndrome, in PS cells. Artificially produced euploid XX PS cells differentiated into mature oocytes in culture with similar efficiency to native XX PS cells. Using this method, we differentiated induced pluripotent stem cells from the tail of a sexually mature male mouse into fully potent oocytes, which gave rise to offspring after fertilization. This study provides insights that could ameliorate infertility caused by sex chromosome or autosomal disorders, and opens the possibility of bipaternal reproduction.

49, XXXXY syndrome

49, XXXXY syndrome is a rare sex chromosomal disorder. A 5-month-old boy had failure to thrive and multiple congenital anomalies including microcephaly, facial dysmorphism (hypertelorism, megacornea, cleft palate, and micrognathia), obvious heart murmur, umbilical hernia, microphallus, and mild clenched hands. Chromosomal studies via techniques of G-banding and fluorescence in situ hybridization showed the constitution to be 47, XXXXY in all cells. Ventriculomegaly and congenital cardiac defects (patent ductus arteriosus, atrial septal defect, and peripheral pulmonary stenosis) were noted. He has severe atopic dermatitis with high IgE levels and psychomotor retardation. After heart surgery and nutritional support, he has better growth and the rehabilitation program is continuing.