Genetic Steroid Disorders

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  • Author : Nicole Reisch
  • Publisher : Elsevier Inc. Chapters
  • Pages : 406 pages
  • ISBN : 0128073047
  • Rating : /5 from reviews
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Download or Read online Genetic Steroid Disorders full in PDF, ePub and kindle. this book written by Nicole Reisch and published by Elsevier Inc. Chapters which was released on 22 August 2013 with total page 406 pages. We cannot guarantee that Genetic Steroid Disorders book is available in the library, click Get Book button and read full online book in your kindle, tablet, IPAD, PC or mobile whenever and wherever You Like. Over the past two decades, genetics of congenital adrenal hyperplasia (CAH) have been extensively studied. The introduction of newborn screening programs in most western countries for CAH caused by 21-hydroxylase deficiency (21OHD) and genetic studies in different ethnic populations have enabled more accurate data concerning the distribution and incidence of CAH and revealed ethnic-specific mutations. Worldwide, the most common mutations in the severe salt-wasting form of 21OHD are the IVS2, the intron 2 splicing mutation, and a large deletion in exon 3. In non-classic 21OHD the most common mutation worldwide is V281L (1685 G to T), being prevalent in about 60% of non-classic patients. This article summarizes the current knowledge on the observed geographical differences of mutation spectra of CAH in specific ethnic groups.

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : Nicole Reisch,Ursula Kuhnle
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
GET THIS BOOK Genetic Steroid Disorders

Over the past two decades, genetics of congenital adrenal hyperplasia (CAH) have been extensively studied. The introduction of newborn screening programs in most western countries for CAH caused by 21-hydroxylase deficiency (21OHD) and genetic studies in different ethnic populations have enabled more accurate data concerning the distribution and incidence of CAH and revealed ethnic-specific mutations. Worldwide, the most common mutations in the severe salt-wasting form of 21OHD are the IVS2, the intron 2 splicing mutation, and a large deletion in exon 3.

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : Maria I. New
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
GET THIS BOOK Genetic Steroid Disorders

This book demonstrates that each steroid disorder causing both clinical and biochemical abnormalities in patients now has a genetic basis. The genes for each step in steroidogenesis have been mapped and cloned, and the mutations in the gene causing the disorder have been described. In addition, the structural biology of the protein resulting from the mutation in the gene has been reported for many of the disorders.

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : Phyllis W. Speiser
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
GET THIS BOOK Genetic Steroid Disorders

Congenital adrenal hyperplasia (CAH) is among the group of inherited disorders now included in newborn screening programs throughout the USA and in many other developed countries. As patients are diagnosed earlier and survive longer into adult life, current therapeutic dilemmas concern individual quality of life, adherence to ethical principles of medical practice, and cost–benefit analysis. This paper will discuss current thinking on selected controversies in the medical and surgical management of CAH. This discussion is based mainly on expert

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : Walter L. Miller,Zoran S. Gucev
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
GET THIS BOOK Genetic Steroid Disorders

Steroidogenesis begins with internalization of low-density lipoprotein particles and subsequent intracellular processing of cholesterol. Disorders in these steps include adrenoleukodystrophy, Wolman disease, and Niemann–Pick type C disease, which may present as adrenal insufficiency. Cholesterol delivery to the inner mitochondrial membrane is regulated by the steroidogenic acute regulatory protein, StAR, and cholesterol is converted to pregnenolone within mitochondria by the cholesterol side chain cleavage enzyme, P450scc. Severe StAR mutations cause classic congenital lipoid adrenal hyperplasia (CAH), characterized by adrenal

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : Christa E. Flück,Amit V. Pandey
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
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Cytochrome P450 oxidoreductase (POR) is an enzyme that is essential for multiple metabolic processes; chiefly among them are reactions catalyzed by cytochrome P450 proteins for metabolism of steroid hormones, drugs, and xenobiotics. Mutations in POR cause a complex set of disorders that often resemble defects in steroid metabolizing enzymes 17-hydroxylase, 21-hydroxylase, and aromatase. Since the initial reports of POR mutations in 2004, more than 70 different mutations and polymorphisms in the POR gene have been identified and tested for their effect on

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : Maria I. New,Oksana Lekarev,Denesy Mancenido,Alan Parsa,Tony Yuen
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
GET THIS BOOK Genetic Steroid Disorders

Congenital adrenal hyperplasia (CAH) refers to a group of autosomal recessive genetic disorders that arise from defective steroidogenesis. The 21-hydroxylase deficiency (21OHD) is the most common form of CAH, accounting for more than 90% of cases. It is the most common disorder of sexual development (DSD) in females. The gene is encoded by CYP21A2, which is located on the short arm of chromosome 6 (6p21.3). The activity of the enzyme 21-hydroxylase, encoded by the CYP21A2 gene, is deficient, leading to

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : Yewei Xing,John C. Achermann,Gary D. Hammer
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
GET THIS BOOK Genetic Steroid Disorders

The adrenal glands comprise two distinct endocrine organs: the inner medulla and the outer cortex. The inner medulla is made up of neuroectodermal cells derived from the neural crest and produces the catecholamine hormones norepinephrine and epinephrine, which are crucial for stress responses. The outer cortex is derived from the mesoderm and synthesizes steroid hormones that are essential to maintain fluid and electrolyte balance, modulate intermediary metabolism and regulate inflammatory processes. Steroidogenesis in the adrenal cortex is mainly regulated by

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : Felix Beuschlein
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
GET THIS BOOK Genetic Steroid Disorders

Adrenal disorders that are caused by specific genetic alterations comprise a heterogeneous group of diseases with mostly low incidence that can affect patients from birth to adulthood. These conditions include failure of proper adrenal development resulting in adrenal agenesis or, conversely, adrenal tumorigenesis. Furthermore, deficiencies of adrenal steroidogenesis result in a lack or a shift of adrenal steroid production that can cause a specific clinical phenotype. For functional studies of gene products, mouse models remain to be intensively utilized as

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : David E. Reichman,Zev Rosenwaks
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
GET THIS BOOK Genetic Steroid Disorders

Human genetic steroid defects have profound impacts on the reproductive potential of affected individuals. Fortunately, advances in our understanding of the genetic and physiologic nuances of these disorders have led to the successful restoration of fertility for patients with several such diseases. In this chapter, the genetic steroid disorders will be explored with respect to their effects on human reproduction, the mechanisms whereby fertility is limited or precluded will be described, and existing as well as emerging therapies for genetic

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : Yves Morel,Florence Roucher,Ingrid Plotton,Jacques Simard,Mauricio Coll
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
GET THIS BOOK Genetic Steroid Disorders

The transformation of Δ5-3β-hydroxysteroids into the corresponding Δ4-3-keto-steroids is an essential step for the biosynthesis of all classes of active steroids: progesterone, mineralocorticoids, glucocorticoids, androgens, and estrogens. These steroid hormones play a crucial role in the differentiation, development, growth, and physiological function of most human tissues. The 3β-HSD deficiency (OMIM +201810), transmitted in an autosomic recessive disorder, is characterized by varying degrees of salt wasting; in genetic males, fetal testicular 3ß-HSD deficiency causes an undervirilized male genitalia (male pseudohermaphroditism);

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : Perrin C. White
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
GET THIS BOOK Genetic Steroid Disorders

Humans have two isozymes with 11β-hydroxylase activity that are respectively required for cortisol and aldosterone synthesis. CYP11B1 (11β-hydroxylase) converts 11-deoxycortisol to cortisol and 11-deoxycorticosterone to corticosterone, is expressed at high levels and is regulated by ACTH. CYP11B2 (aldosterone synthase) is normally expressed at low levels and is regulated mainly by angiotensin II and potassium levels. The latter enzyme also has 18-hydroxylase and 18-oxidase activities and thus can synthesize aldosterone from deoxycorticosterone. Mutations in the CYP11B1 gene cause

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : Heino F.L. Meyer-Bahlburg
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
GET THIS BOOK Genetic Steroid Disorders

The syndromes of congenital adrenal hyperplasia, particularly their classical variants, present diverse medical and psychosocial challenges to the affected individual that may affect all stages of life from the prenatal phase through old age. This chapter reviews the psychological outcomes in terms of gender, general cognitive development, psychopathology, sexuality, and quality of life, the factors that contribute to these outcomes, including neuroanatomy and brain function, and the implications for the clinician and the organization of health services.

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : John W. Funder
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
GET THIS BOOK Genetic Steroid Disorders

Apparent mineralocorticoid excess (AME) reflects absent or impaired activity of the enzyme 11β-hydroxysteroid dehydrogenase type 2, allowing cortisol to activate epithelial mineralocorticoid receptors inappropriately. In the absence of enzyme activity patients show classic features of mineralocorticoid excess, with a diagnostic triad of hypertension, suppressed aldosterone levels, and raised urinary free cortisol:cortisone ratios. Severe AME (10%) can be diagnosed on the basis of the diagnostic triad, but do not show the associated spectrum of clinical disorders. Treatment of severely affected neonates needs

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : Richard J. Auchus
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
GET THIS BOOK Genetic Steroid Disorders

Steroid 17-hydroxylase 17,20-lyase (cytochrome P450c17, CYP17A1) occupies a critical position in the pathways of human steroidogenesis, regulating the classes of steroid hormones produced by cells of the adrenal glands and gonads. CYP17A1 catalyzes two major reactions: the 17-hydroxylase and 17,20-lyase reactions. Mutations that compromise all CYP17A1 activities cause combined 17-hydroxylase/17,20-lyase deficiency, which presents as hypertension, hypokalemia, and sexual infantilism. A few mutations selectively impair 17,20-lyase activity, and some mutations in cofactor proteins cytochrome P450-oxidoreductase

Genetic Steroid Disorders

Genetic Steroid Disorders
  • Author : David W. Russell,Jean D. Wilson
  • Publisher : Elsevier Inc. Chapters
  • Release : 22 August 2013
GET THIS BOOK Genetic Steroid Disorders

Loss-of-function mutations in the steroid 5α-reductase 2 gene (SRD5A2) cause a disorder of male sexual differentiation in which the prostate does not form and external genitalia develop along female lines. Failure to synthesize dihydrotestosterone in fetal tissues that give rise to the male urogenital tract underlies the phenotype that characterizes this disorder. Studies of the SRD5A2 gene and its encoded enzyme at the molecular, biochemical, and endocrinological levels established the crucial role of dihydrotestosterone in formation of the male