Genetic, epigenetic and enviromental influencing factors on the regulation of precocious and delayed puberty.

The pubertal development onset is controlled by a network of genes that regulate the gonadotropin releasing hormone (GnRH) pulsatile release and the subsequent increase of the circulating levels of pituitary gonadotropins that activate the gonadal function. Although the transition from pre-pubertal condition to puberty occurs physiologically in a delimited age-range, the inception of pubertal development can be anticipated or delayed due to genetic and epigenetic changes or environmental conditions. Most of the genetic and epigenetic alterations concern genes which encode for kisspeptin, GnRH, LH, FSH and their receptor, which represent crucial factors of the hypothalamic-pituitary-gonadal (HPG) axis. Recent data indicate a central role of the epigenome in the regulation of genes in the hypothalamus and pituitary that could mediate the flexibility of pubertal timing. Identification of epigenetically regulated genes, such as Makorin ring finger 3 (MKRN3) and Delta-like 1 homologue (DLK1), respectively responsible for the repression and the activation of pubertal development, provides additional evidence of how epigenetic variations affect pubertal timing. This review aims to investigate genetic, epigenetic, and environmental factors responsible for the regulation of precocious and delayed puberty.

Role of antithyroid autoimmunity as a predictive biomarker of chronic immune thrombocytopenia.

BACKGROUND: Immune thrombocytopenia (ITP) is an acquired immune-mediated disorder characterized by isolated thrombocytopenia. Pediatric ITP patients are prone to develop autoantibodies such as antithyroglobulin (TG) and antithyroperoxidase (TPO), even in the absence of clinical signs of autoimmune disease. The aim of this multicenter retrospective study was to evaluate (1) the prevalence of positivity of antithyroid antibodies (TPO and TG) in a large cohort of pediatric patients with chronic ITP; (2) the role of autoimmune thyroiditis as a prognostic factor for chronicity of ITP. PROCEDURE: For this retrospective study, we collected data from patients diagnosed as affected by chronic ITP between 2011 and 2014 in six centers belonging to the Italian Association of Pediatric Haematology and Oncology (AIEOP). RESULTS: From the analysis of data, we found a significantly higher prevalence of antithyroid antibodies in children with chronic ITP (11.6%) than in the pediatric population (1.2%-1.3%). No correlation has been found between the platelet count and the prevalence of positive antithyroid antibodies at any detection time of the study. CONCLUSIONS: The results of our study demonstrated that (1) the prevalence of positivity for antithyroid antibodies (anti-TPO and anti-TG) in pediatric patients with chronic ITP results is significantly higher than in the pediatric population; (2) autoimmune thyroiditis does not seem to play a role as a prognostic factor for chronicity of ITP in pediatric patients.

Unusual pediatric co-morbility: autoimmune thyroiditis and cortico-resistant nephrotic syndrome in a 6-month-old Italian patient.

We report on a case of autoimmune thyroiditis in a 6-month-old patient with cortico-resistant nephrotic syndrome. Normal serum levels of thyroid hormons and thyroid-stimulating hormone were detected with high titers of circulant antithyroid antibodies and a dysomogeneous ultrasound appearance of the gland, typical of autoimmune thyroiditis. The research of maternal thyroid antibodies was negative. This is the first case of autoimmune thyroiditis found in such a young patient with pre-existing nephrotic syndrome ever described in literature. This association is random because nephrotic syndrome does not have an autoimmune pathogenesis and the genes involved in autoimmune thyroiditis are not related to those of nephrotic syndrome.