The clinical and genetic heterogeneity of mixed gonadal dysgenesis: does “disorders of sexual development (DSD)” classification based on new Chicago consensus cover all sex chromosome DSD?

Clinical findings illustrate the wide spectrum of the phenotypic manifestations of 45,X/46,XY mosaicism in the sex chromosome disorders of sex differentiation (DSD). The objective of study is to evaluate the characteristics of 45,X/46,XY patients and questioning of their place within the DSD categorization. The clinical findings of 11 patients with 45,X/46,XY mosaicism are described including the presentation, gonadal morphology, genital anatomy, and the hormone levels among 285 patients with DSD evaluated. Sixty-seven patients were diagnosed with sex chromosome DSD (50 Turner, three Klinefelter, ten 45,X/46,XY gonadal disgenesis, one 45X/46,XY ovotesticular DSD, one 47,XYY ovotesticular DSD, and two 46,XX/46,XY ovotesticular DSD). The type and the percentage of patients with 45,X/46,XY mosaicism were as follows: Four cases of mix gonadal dysgenesis, four cases of partial gonadal dysgenesis, two cases of complete gonadal dysgenesis, one case of ovotesticular DSD. On the other hand, another patient that has 45,X/46,XX mosaicism was diagnosed with MGD with the presence of the streak gonad on the right side and the testis on the other side. Conclusion: We suggest that sex chromosome DSD categorization can include 45,X/46,XY PGD and 45,X/46,XY CGD. Mixed gonadal dysgenesis may be also placed among the disorders of testicular differentiation of 46,XY DSD subdivision.