X-autosome and X-Y translocations in female carriers: X-chromosome inactivation easily detectable by 5-ethynyl-2-deoxyuridine (EdU)

Here we report one new case each of an X-autosome translocation (maternally derived), and an X-Y-chromosome translocation. Besides characterizing the involved breakpoints and/or imbalances in detail by molecular cyto-genetics, also skewed X-chromosome inactivation was determined on single cell level using 5-ethynyl-2-deoxyuridine (EdU). Thus, we confirmed that the recently suggested EdU approach can be simply adapted for routine diagnostic use. The latter is important, as only by knowing the real pattern of the skewed X-chromosome inactivation, correct interpretation of obtained results and subsequent reliable genetic counseling, can be done.