Structural aberrations of the X chromosome in man.

Among 209 patients with Shereshevsky-Turner syndrome, 69 women with structural aberrations of X chromosome were detected: 46,X,i(Xq) - 11; 45,X/46,X,i(Xq) - 24; 45,X/46,X,r(X) - 14; 45,X/46,X,f(X or Y) - 10; 45,X/46,X,del(Xq) - 4; 45,X/46,X,del(Xp) - 2; 45,X/46,X,idic(X) - 2; 46,X,idic(X) - 1; and 46,X,t(X,2) - 1. All the patients with structural abnormalities of X chromosome were short in stature, but in no group was it as low on the average as in 45,X cases. Somatic signs were noticed in all structural changes of X, but they were less frequent and less pronounced. In some patients with r(X) and i(Xq), spontaneous menstrual bleeding and breast development was found. The structurally abnormal X chromosome appears to be functionally inactive, the phenotype of patients with structural rearrangements being close to the phenotype of patients with X monosomy. At the same time, the abnormal X might have certain effects in early embryogenesis which mitigated the further development of the Shereshevsky-Turner syndrome.