RESUMO
OBJECTIVES: Disorders of sex development (DSD) include a group of conditions in which genotypes do not correlate with the typical male and female phenotypes. Numerical and structural abnormalities involving both autosomes and sex chromosomes have been observed in DSD. Specifically, deletions, duplications, and translocations involving specific genes as well as point mutations and less common aberrations have been implicated in the pathogenesis of these conditions. Finally, recent advances in analytical tools, namely chromosomal microarrays and sequencing methods, have greatly enhanced the precision with which DSD are genetically characterized and phenotypically correlated. Herein we report a case of a 24-year-old female patient who presented with secondary amenorrhea. Cytogenetic studies of her peripheral blood showed an abnormal clone with 45,X in three cells and the other was initially observed by chromosome analysis as 46,X,+mar in 27 cells. Molecular cytogenetics were performed to characterize the marker chromosome that showed two copies of the SRY, two copies of the heterochromatin Yq12, and two copies of the Y centromere Yp11.1-q11.1 on the marker chromosome, resulting in the identification of an isodicentric Y chromosome. Females with a 46,XY karyotype have gonadal dysgenesis and typically present as mosaic, along with a 45,X cell line. Some show small deletions of the short arm of the Y chromosome. Further studies based on the clinical picture, as well as possible prophylactic gonadectomy due to an increased risk of gonadal malignancy, gonadoblastoma or dysgerminoma, are suggested. Genetic counseling was recommended.
