Turner syndrome caused by rare complex structural abnormalities involving chromosome X.

Turner syndrome (TS) is a phenotypic heterogeneous genetic disorder caused by the loss of an X-chromosome or X-structural abnormalities in the X-chromosome, and affects approximately 1 in every 2,500 females. The affected individuals may develop diverse clinical features, including short stature, ovarian dysgenesis, skeletal dysplasia, facial abnormalities and other disorders. A constitutional karyotype of 45, X accounts for nearly 50% of TS patients, while X-mosaicism and other X-chromosomal structural abnormalities, including deletions, duplications, ring, isodicentric chromosomes, inversions and translocations, have been reported in other cases. The present study reports the results of chromosome microarray analysis (CMA) in two Chinese female TS patients with idiosyncratic karyotypes. The first patient had a karyotype of 46, X, der(X), and the CMA results demonstrated that the derivative chromosome was an abnormal X-chromosome that consisted of three deletions (Xp21.3-p11.23, Xp11.1-q13.1 and Xq21.31-q28), as well as three duplications (Xp22.33-p21.3, Xp11.23-p11.1 and Xq13.1-q21.31). The karyotype of the second patient was 46, X, der(X) t(X;?)(q 22.1;?),inv(11)(q13.5q21), while CMA revealed an Xq21.2-q27.1 duplication and an Xq27.2-q28 deletion. In conclusion, the current study performed genotype-phenotype correlation analysis in two patients and provided novel insight of the genotype of TS.