Ovarian differentiation in Turner's syndrome

The authors have studied the gonadal histogenesis and the sexual chromosome influence on the gonads of 17 patients with the following complements : 45,X/46,XXqi (1 case); 45,X (4 cases); 45,X/46,XXP--(1 cases); 45,Xq-- (1 case); 45,X/46,XX (8 cases); 45,X/46,XX/46,XXqi (1case); and 45,X/46,XXqi/47,XXqiXqi (1 case). The presence of sexual differentiation structures was investigated : coelomic epithelium, stromal characteristics, follicles sexual cords, medullary tubules, rete ovarii, hilar cells, mesonephric remnants and coelomic epithelium inclusions. All gonads were constituted by rudimentary ovarian stroma with different states of hyalinization. Primordial follicles were noted in two patients with respectively 45,X/46,XX and 45,X/46,XXqi/47,XXqiXqi karyotypes, and a cystic follicle was present in one patient 45,X/46,XXp--. Sexual cords were seen in 6 patients and medullary tubules in 9. Different amounts of hilar cells were found as well. The authors conclude that in Turner's syndrome there exists an ovarian dysgenesis which is probably caused by early involution before reaching the maturation, conditioned by the genetic incapacity of the oogonia to complete the meiotic prophase.     

Phenotype spaces

The topological viewpoint on spaces of phenotypes presented in Stadler et al. (J Theor Biol 213:241–274, 2001) is revisited, and a quantified version is proposed. While necessary probabilistic information can be encoded in a topological- like fashion, it turns out that it is not reflected adequately by the concept of continuity. We propose alternative models, but the behavior of maps make these models non-topological in fundamental ways.