Rescue from the effects of trisomy 13q32→qter owing to skewed X inactivation in a der(X)t(X;13)(p21;q32) carrier

In patients with an X;autosome translocation, X inactivation occurs at random but is followed by cellular selection, favouring the better genetic balance. 3 Accordingly, nearly 95% of patients with balanced X;autosome translocations show a skewed inactivation of the normal X chromosome in almost all cells, thereby avoiding somatic monosomy or X chromosome disomy, while patients with unbalanced X;autosome translocations have the der(X) constantly inactivated in 91% of the cases in order to obtain the most optimal balance of the genome. 1 We report here a woman who was referred for chromosome analysis because of four consecutive first trimester spontaneous miscarriages following the birth of a healthy daughter. [...]apparently pure deletions of the X chromosome should be investigated further in order to exclude X;autosome translocations, which may have an influence on the phenotype.