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The aim of this study was to verify the influence of Y chromosome and intrauterine androgens production/action on birth weight and length of children with Disorders/Differences of Sex Development (DSD). This was a cross-sectional and retrospective study. Cases of Turner syndrome (TS), complete (XX and XY), mixed (45,X/46,XY) and partial (XY) gonadal dysgenesis (GD), complete (CAIS) and partial (PAIS) androgen insensitivity syndromes and XX and XY congenital adrenal hyperplasia (CAH) were included. Such conditions were grouped according to karyotype and to intrauterine production/action of androgens. The sample consisted of 293 cases, 50 with TS, 28 mixed GD, 117 CAH (49 XY and 68 XX), 18 CAIS, 10 PAIS, 30 partial GD, 10 XY and 30 XX complete GD. Birth weight and length were lower in TS and mixed GD when compared to XY and XX. In turn, patients with increased androgen production/action (117 cases) had higher birth weight and length when compared to those with absent (108 cases) and decreased (68 cases) production/action. It was observed a negative influence of the 45,X/46,XY karyotype in birth weight and a positive influence of increased androgen production/action. Regarding birth length, there was a negative influence of the TS karyotype and of decreased androgen production/action. In conclusion, in DSD, both karyotype, especially with a 45,X cell line, and intrauterine androgenic production/action influence sex dimorphism of birth weight and length. It can be inferred that in children with normal karyotype and without a DSD, this dimorphism is mainly due to intrauterine androgenic production or action.

Objective This meta-analysis aims evaluate the association of the polymorphism rs9939609 of FTO with the risk of obesity among children and adolescents, based on the assessment of four genetic models: codominant, dominant, recessive alleles model. Methods Case-control studies, published between the years 2011–2015, were selected from tree available databases (PubMed, Scopus and Web of Science) and were analysed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. Thirteen studies were included totalling 15,613 participants, divided into 7311 cases and 8302 controls. Results The FTO rs9939609 polymorphism was significantly associated with increased risk of obesity in children and adolescents for homozygous genotypes AA and heterozygous AT (TT vs. AT + AA: OR = 0.723, 95% CI 0.629 to 0.832; p Conclusion This meta-analysis shows that the FTO rs9939609 polymorphism in the gene is a risk factor for obesity in children and adolescents with the presence of the A allele, both homozygous genotype AA situation, as heterozygous AT.