ESPE Abstracts

A broad spectrum of human diseases, including abnormalities in steroidogenesis, are caused by mutations in the NADPH cytochrome P450 oxidoreductase (POR) (1-4). Human POR is a diflavin reductase that transfers electrons from NADPH to small molecules, non-P450 redox partners and cytochrome P450 proteins in the endoplasmic reticulum. Cytochrome P450 proteins perform a very wide range of reactions, including metabolism of steroids, drugs and other xenobiotics. Therefore, genetic ...

Background: Generalized lymphatic anomaly (GLA) is a rare congenital disorder characterized by aggressive proliferation of dilated lymphatic vessels. The etiology of GLA is poorly understood.Objective and hypotheses: To identify the underlying genetic basis for GLA.Method: Exome sequencing (ES) was performed in two families, including a multigenerational family (family-1) with six affected members. RNA-seq was performed on skin bio...

Introduction: Over-production of androgens is linked to prostate cancer (PCa) in men and polycystic ovary syndrome (PCOS) in women. CYP17A1 produces dehydroepiandrosterone (DHEA), the precursor for androgens, via its 17,20 lyase activity. CYP17A1 lyase activity is regulated by the amount of P450 reductase for electron transfer; the presence of cytochrome b5; and protein phosphorylation. High androgen levels were linked to the phosphorylation of CYP17A1 protein...

Background: Thyroid hormone disrupting chemicals (THDCs) which are present in the environment, food and everyday consumer products, interfere with thyroid hormone signaling, possibly by interacting with thyroid hormone receptors (THRs). This alters the thyroid hormone homeostasis and affects various functions regulated by the thyroid hormone e.g. macronutrient metabolism, cardiovascular function, and normal brain development. Therefore, there is a necessity for detection and m...

Background: Mutations in GH1 gene cause isolated growth hormone deficiency. Several disease-causing mutations from patients with IGHD have been reported. These mutations have been shown to (a) produce shorter isoforms of GH that does not bind to growth hormone receptor, (b) cause diminished secretion of GH or (c) result in misfolded GH protein. Large sequencing studies from the non-clinical population show several hundred genetic variations in GH1 gene. Role of common polymorp...

Congenital adrenal hyperplasia (CAH) is a common disorder of steroid production mainly caused by a mutated CYP21A2 gene, causing 21-hydroxylase deficiency (21OHD). CAH due to 21OHD requires lifelong mineralocorticoid (MC) and glucocorticoid (GC) therapy. But, from the location of the enzyme block in the steroid production and increase of adrenocorticotropic hormone (ACTH) which stimulates the melanocortin type 2 receptor (MC2R) in the adrenal, excessive adrenal androgen produc...

Mutations in the GH1 gene cause isolated growth hormone deficiency (IGHD) by affecting production, secretion, and stability of growth hormone as well as its binding to GHR. A smaller isoform of GH1 is inactive and is linked to IGHD. While studying the impact of small GH isoform, we noticed that cells with the short 17.5 kD version of GH looked different from the control cells. We found that the production of short GH isoform distorts the cell morphology, contributing to detrim...

Background: The cytochrome P450 CYP17A1 plays a vital role in regulating adrenal androgen production. The 17,20 lyase activity of CYP17A1 is key for androgen regulation. The orteronel and galeterone are known to inhibit 17,20 lyase activity however the detailed mechanisms of the inhibition of CYP17A1 activities remain unknown. These inhibitors have been developed to treat the castration resistant prostate cancer (CRPC) but little is known about their effects on adrenal androge...

Background: Cardiomyopathy is a heterogeneous group of disorder of myocardium associated with mechanical and/or electrical dysfunction that usually exhibit inappropriate ventricular hypertrophy or dilatationleading to heart failure. Congenital adrenal hyperplasia (CAH) due to 11β-hydroxylase deficiency is rare inherited disorder of cortisol biosynthesis, due to genetic defects of CYP11B1 gene presenting as hypertension, features of androgen excess, and peripheral precocio...

Cytochrome P450 oxidoreductase (POR) is the obligatory redox partner of steroid and drug-metabolizing cytochrome P450s located in the endoplasmic reticulum. Mutations in POR cause a broad range of disorders like congenital adrenal hyperplasia that may resemble bone malformations resembling Antley-Bixler syndrome. Genome sequencing studies have revealed the existence of a POR missense variant P228. We aimed to determine the detailed functional impact of POR variant P228L for it...