Microdeletions in the AZF region of the Y chromosome in patients with Disorders of Sexual Developmental (DSD) due to 45,X/46,XY chromosomal abnormalities and variants.

Abstract

Mammalian sexual development depends on a complex network of regulatory genes, signaling proteins, hormones, and their cellular receptors. Failures in the processes of sex determination and differentiation can generate abnormalities in the individual's sexual development. Those congenital conditions are called Disorders of Sexual Developmental (DSD). DSD can be classified into several categories including any condition in which there are alterations in the constitution of the sex chromosomes, leading to the manifestation of genital atypia, Disorders of Pubertal Development, gonadal failure, infertility, and other stigmas and body dysmorphisms. Patients with 45,X/46,XY mosaicism or variants, who have more than two cell lineages and structural anomalies in the Y chromosome will be studied in this project owing to the importance in clinical practice and the frequency or spectrum of clinical-therapeutic repercussions. Forgoing research that studied patients with the mosaicism associated the etiology of that condition to a group of genes called Azoospermia Factor (AZF) located at a specific region of the Y (Yq). AZF consists in three sub-regions: AZFa, AZFb and AZFc. It is acknowledged that the absence of these segments is more prevalent in azoospermic men or with severe oligozoospermia, moreover some studies indicate that this structural loss is related to the formation of 45,X lineages. From then on, it is considered that deletions in these sub-regions, in particular AZFc, may predispose to Y loss, leading to 45,X/46,XY mosaic chromosomal DDS and variants. This project aims to investigate the presence of microdeletions in the Y in 7 patients with mosaicism or its variants and their respective parents, followed up at the Hospital das Clínicas, Faculdade de Medicina da USP, using individual and multiplex PCR (Polymerase Chain Reaction) techniques, in which 34 STSs (Sequence Tagged Sites) will be analyzed. The results will contribute to a better understanding of the etiology of this condition and establish possible associations of variations in the number of copies of Yq genes with the manifested phenotypic characteristics and gonadal tumors frequently presented by patients with mixed gonadal dysgenesis.