Search for mutations in PTGDS, MAP3K1, FGF9/FGFR2 genes from amplification pathway of SOX9 gene in patients with 46,XY gonadal dysgenesis

Abstract

In mammals the gene Sox9 plays a preponderant role in the development process of the embryonic gonad male, a fact that is evidenced by the existence of various mechanisms for amplification of Sox9 by a positive feedback loop. The Ptgds, MAP3K1, FGF9 genes and its receptor FGFR2 participate in the process of sustaining male gonadal development pathway, from amplification of Sox9. The various experimental evidence of involvement of these genes in the development process of the male gonad suggest that dysfunction of these, cause abnormalities in the dynamics of the determination and development of testicular dysgenetic gonads. The existence of positive feedback amplification of the genes Sox9 and L-PGDs was confirmed by studies in animal models, but to date no mutations in humans have been described. Recently, mutations in MAP3K1 gene have been described in patients with 46,XY non-syndromic gonadal dysgenesis. Functional studies of the MAP3K1 protein mutated identified change in phosphorylation of target cascade below as p38 and ERK1/2 and increased protein binding to the complex RHOA and MAP3K. In animal models, the presence of anomalies in gonadal development has been linked to the loss of function in FGF9 gene and FGFR2. These reports led to the search of inactivating mutations in both genes in patients with 46, XY gonadal dysgenesis developed as dissertation. As a result of this research, a new variant, c.1358 C> T (p.Ser453Leu), located in exon 10 of FGFR2 was identified as heterozygous in two sisters with DGP 46, XY and mother. This variant was not found in 147 individuals 46,XY controls studied. The objective of this project is to evaluate the involvement of genes PTGDS, MAP3K1 and FGF9/FGFR2 genes involved in the positive feedback pathway of SOX9 gene in patients with 46,XY DSD by abnormalities on testicular development. The presence of mutations in MAP3K1 and PTGDS will be investigated in 33 patients with DDS 46,XY by abnormalities in gonadal development in which FGF9 and FGFR2 genes have been studied. Functional studies of new allelic variant of the FGFR2 p.Ser453Leu identified in the previous study will be conducted in collaboration with Prof.. Dr. Vincent Harley of Prince Henry's Institute in Melbourne, Australia. This study will include an analysis "in vivo" and "in vitro" of FGFR2 mutated. The possible effects on the cellular activities of apoptosis in gonadal tissue secondary to conformational and structural changes of the new FGFR2 protein will be evaluated by histological paraffin embedded tissues of patients with allelic variant using immunohistochemistry with anti-caspase 3 and TUNEL technique.