Family case of mosaic variant of Turner syndrome with ring X chromosome

Abstract

The article presents a clinical case of Turner syndrome (TS) in a mother and her two daughters. Standard cytogenetic examination using by GTG-staining technique found mosaic karyotype with two cell lines, one clone with monosomy X (45,X) and other one with ring X-chromosome - 46,X,r(X)(p22.3q28). Fluorescent in situ hybridization revealed gonosomal mosaicism mos X/X,r(X) in peripheral blood lymphocytes and buccal epithelial cells in all patients. There number of cells containing ring X chromosome were similar in lymphocytes (8-11%), and were more varied in buccal epithelium (26-47%) between patients. Analysis of X chromosome inactivation (XCI), performed in the mother and her eldest daughter, revealed skewed inactivation of ring X chromosome. The patients had a similar phenotype signs characterized to Turner syndrome, but fertility was preserved at least in the mother and her eldest daughter. Reported in the literature familial TS cases with ring X chromosome are reviewed.