Turner syndrome
Turner syndrome, also known as 45,X or 45,X0, is a chromosomal abnormality characterised by a partial or completely missing second X chromosome,
giving a chromosomal count of 45, instead of the typical count of 46 chromosomes.Dysregulation in meiosis signalling to germ cells during embryogenesis may result in nondisjunction and monosomy X from separation failure of chromosomes in either the parental gamete or during early embryonic divisions.The aetiology of Turner syndrome phenotype can be the result of haploinsufficiency, where a portion of critical genes are rendered inactive during embryogenesis. Normal ovarian development requires these vital regions of the X chromosome that are inactivated. Clinical manifestation include primary amenorrhea, hypergonadotropic hypogonadism, streak gonads, infertility, and failure to develop secondary sex characteristics. Turner syndrome is not diagnosed until a delayed onset of puberty with Müllerian structures found to be in infantile stage. Physical phenotypic characteristics include short stature, dysmorphic features and lymphedema at birth.Comorbidities include heart defects, vision and hearing problems, diabetes, and low thyroid hormone production. Endocrine disruptions
Endocrine disruptors interfere with the endocrine system and hormones. Hormones are critical for the correct events in embryogenesis to occur.Foetal development relies on the proper timing of the delivery of hormones for cellular differentiation and maturation. Disruptions can cause sexual development disorders leading to gonadal dysgenesis. Diagnosis
Management
History
Turner syndrome was first described independently by Otto Ulrich in 1930 and Henry Turner in 1938. 46,XX pure gonadal dysgenesis was first reported in 1960. 46,XY pure gonadal dysgenesis, also known as Swyer syndrome, was first described by Gim Swyer in 1955.
Fenoldopam mesylate (Corlopam) is a drug and synthetic benzazepine derivative which acts as a selective D1 receptor partial agonist. Fenoldopam is used as an antihypertensive agent. It was approved by the Food and Drug Administration (FDA) in September 1997. Indications
Fenoldopam is used as an antihypertensive agent postoperatively, and also intravenously (IV) to treat a hypertensive crisis. Since fenoldopam is an intravenous agent with minimal adrenergic effects that improves renal perfusion, in theory it could be beneficial in hypertensive patients with concomitant chronic kidney disease. It can cause reflex tachycardia, but it is dependent on the infusion of the drug. Pharmacology
Fenoldopam causes arterial/arteriolar vasodilation leading to a decrease in blood pressure by activating peripheral D1 receptors. It decreases afterload and also promotes sodium excretion via specific dopamine receptors along the nephron. The renal effect of fenoldopam and dopamine may involve physiological antagonism of the renin-angiotensin system in the kidney. In contrast to dopamine, fenoldopam is a selective D1 receptor agonist with no effect on beta adrenoceptors, although there is evidence that it may have some alpha-1  and alpha-2 adrenoceptor antagonist activity. D1 receptor stimulation activates adenylyl cyclase and raises intracellular cyclic AMP, resulting in vasodilation of most arterial beds, including renal, mesenteric, and coronary arteries. to cause a reduction in systemic vascular resistance. Fenoldopam has a rapid onset of action (4 minutes) and short duration of action (< 10 minutes) and a linear dose–response relationship at usual clinical doses. Side effects
Adverse effects include headache, flushing, nausea, hypotension, reflex tachycardia, and increased intraocular pressure.