Arrest of human oocytes during meiosis I in two sisters of consanguineous parents: first evidence for an autosomal recessive trait in human infertility: Case report.

Two sisters descended from consanguineous parents underwent unsuccessful IVF treatments. Their oocytes showed neither a first or second polar body, nor pronuclei. After cytogenetic preparation, all oocytes were characterized by condensed maternal metaphase I chromosomes and premature chromosome condensation of the sperm nucleus. Both women exhibited a normal female karyotype (46,XX). The pedigree of the family revealed two other sisters who had delivered children, but also two brothers who had been married for several years without children. There is a strong indication for an autosomal recessive trait responsible for the idiopathic infertility due to the expression of a rare recessive allele inherited from common ancestors. However, neither the mechanism of metaphase I arrest nor the gene(s) involved in this arrest are known in the case of our patients. We discuss molecular mechanism(s) derived from animal models that might be involved in this inherited disorder in human oocytes.