Characteristics and mechanisms of X chromosome translocation

Abstract

Abstract Background Individuals with X chromosomal translocation and variable phenotype, high risk of living birth defect constitute an interesting project to study. Those are related to differential breakpoints and types of chromosomal abnormality. To investigate the effect of X translocation and clinical phenotype, a retrospective analysis of the clinical data of patients with X translocation who verified by chromosome karyotype was conducted. The efects of follicle-stimulating hormone (FSH) levels, luteinizing hormone (LH) levels, estradiol (E2), progesterone (PROG), prolactin (PRL), testosterone (T) levels, Anti-Müllerian hormone (AMH) and an additional semen analysis for male were assessed in this group of patients. Results A total of 10 individuals underwent detail clinical data. Infantile uterus and both small ovaries were visible with abdominal ultrasound in two cases (FSH:34.80IU/L, LH:17.06mIU/mL, E2:15.37pg/ml; FISH:6.60IU/L, LH:1.69mIU/mL, E2:23.70pg/ml). No ovaries were visible in one case (FSH:114IU/L, LH:30.90mIU/mL, E2:<5.00pg/ml). Corresponding to the chromosome karyotype results, the breakpoints were located on the long arm of X chromosome(Xq13, 21, 25). Normal endocrine hormonal levels and abilities of fertility were observed in other three cases with breakpoints located on short arm of X chromosome, which appeared unremarkable clinical manifestations, but had a history of abnormal pregnancy results of partial monosomies and trisomies. In addtion, normal phenotype and complex reciprocal translocation were observed in one case with early spontaneous abortion twice. In three cases of male, multiple semen analysis confirmed no sperm. Y chromosome microdeletion analysis and hormonal analysis were performed to be normal. The balanced reciprocal translocation were found between X chromosome and autosome (1, 3 and 8), and breakpoints mainly located on Xq26. Conclusions Our study provides insights into which individuals with X translocation most likely to have ovary insufficiency, infertility and high risk to birth defects. Rely on a full history and physical exam with laboratory evaluation that helps to understand the clinical heterogeneity involved and provide accurate, efficient and personalized genetic counseling.