Sex Reversal in Zebrafish fancl Mutants Is Caused by Tp53-Mediated Germ Cell Apoptosis

The molecular genetic mechanisms of sex determination are not known for most vertebrates, including zebrafish. We identified a mutation in the zebrafish fancl gene that causes homozygous mutants to develop as fertile males due to female-to-male sex reversal. Fancl is a member of the Fanconi Anemia/BRCA DNA repair pathway. Experiments showed that zebrafish fancl was expressed in developing germ cells in bipotential gonads at the critical time of sexual fate determination. Caspase-3 immunoassays revealed increased germ cell apoptosis in fancl mutants that compromised oocyte survival. In the absence of oocytes surviving through meiosis, somatic cells of mutant gonads did not maintain expression of the ovary gene cyp19a1a and did not down-regulate expression of the early testis gene amh; consequently, gonads masculinized and became testes. Remarkably, results showed that the introduction of a tp53 (p53) mutation into fancl mutants rescued the sex-reversal phenotype by reducing germ cell apoptosis and, thus, allowed fancl mutants to become fertile females. Our results show that Fancl function is not essential for spermatogonia and oogonia to become sperm or mature oocytes, but instead suggest that Fancl function is involved in the survival of developing oocytes through meiosis. This work reveals that Tp53-mediated germ cell apoptosis induces sex reversal after the mutation of a DNA–repair pathway gene by compromising the survival of oocytes and suggests the existence of an oocyte-derived signal that biases gonad fate towards the female developmental pathway and thereby controls zebrafish sex determination

Characterizing Early Psychosocial Functioning of Parents of Children with Moderate to Severe Genital Ambiguity due to Disorders of Sex Development

PurposeWe examined the psychosocial characteristics of parents of children with disorders of sex development at early presentation to a disorders of sex development clinic. Parental anxiety, depression, quality of life, illness uncertainty and posttraumatic stress symptoms were assessed. Additionally we evaluated the relationship of assigned child gender to parental outcomes.Materials and methodsA total of 51 parents of children with ambiguous or atypical genitalia were recruited from 7 centers specializing in treatment of disorders of sex development. At initial assessment no child had undergone genitoplasty. Parents completed the Cosmetic Appearance Rating Scale, Beck Anxiety Inventory, Beck Depression Inventory, SF-36, Parent Perception of Uncertainty Scale and Impact of Event Scale-Revised.ResultsA large percentage of parents (54.5%) were dissatisfied with the genital appearance of their child, and a small but significant percentage reported symptoms of anxiety, depression, diminished quality of life, uncertainty and posttraumatic stress. Few gender differences emerged.ConclusionsAlthough many parents function well, a subset experience significant psychological distress around the time of diagnosis of a disorder of sex development in their child. Early screening to assess the need for psychosocial interventions is warranted