CHAPTER 32 – Germ Cell Failure and Ovarian Resistance: Human Genes and Disorders

摘要: This chapter discusses the known disorders of ovarian failure and resistance related genes. Ovarian in humans have a variety causes. Failure may be complete or premature, occurring earlier (younger than 35 40 years) expected age menopause. Either premature has long been deduced to result from either deletions X chromosome Mendelian causes; however, only rarely is actual gene known. Primordial germ cells originate endoderm yolk sac migrate genital ridge form indifferent gonad with 46,XY 46,XX gonads being initially indistinguishable. Indifferent develop into testes if embryo, more specifically gonadal stroma, 46,XY. Testes become morphologically identifiable 7 8 weeks following conception (9 10 gestational menstrual weeks). Ovaries thereafter. In absence Y chromosome, develops an ovary. Transformation fetal ovaries begins at 50 55 days embryonic development. It debatable whether female (ovarian) differentiation truly default (constitutive) pathway, specific product directs primary differentiation.