Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Genetic Steroid Disorders
Download Genetic Steroid Disorders full books in PDF, epub, and Kindle. Read online Genetic Steroid Disorders ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Genetic Steroid Disorders by : Maria I. New
Download or read book Genetic Steroid Disorders written by Maria I. New and published by Academic Press. This book was released on 2023-06-14 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: Genetic Steroid Disorders, Second Edition targets adult and pediatric endocrinologists, clinical geneticists, genetic counselors, reproductive endocrinologists, neonatologists, urologists, and psychoendocrinologists. It is designed to assist these specialists in the diagnosis and treatment of steroid disorders. This revision includes a new chapter on "Gonadotropins, Obesity and Bone" and new research on non-invasive prenatal diagnosis with cell-free DNA. Chapters are thoroughly updated covering steroid disorders, the genetic bases for the disorder and case presentations, This definitive reference belongs in every medical library! Presents a comprehensive, translational look at all aspects of genetic steroid disorders in one reference work Provides a common language for endocrinologists, geneticists, molecular pathologists, and genetic counselors to discuss and diagnose genetic steroid disorders Saves clinicians and researchers time in quickly accessing the very latest details on genetic tests and diagnoses as opposed to searching through thousands of journal articles Highlights significant discoveries with clinical relevance, presenting insight into which medications to use based on the genetic makeup of a patient Teaches the best strategies and most effective use of genetic information in the patient counseling setting
Book Synopsis Genetic Steroid Disorders by : Maria I. New
Download or read book Genetic Steroid Disorders written by Maria I. New and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 an accumulation of 17-hydroxyprogesterone (17-OHP) and subsequent elevation of androgens. The three forms of 21OHD are the salt-wasting form, simple-virilizing form, and non-classical form. The first two forms are classical forms of the disease where the hallmark finding is ambiguity of the genitalia in affected female newborns. Patients with the non-classical form have normal genitalia, yet may present with signs of early sexual development and other symptoms of hyperandrogenemia such as short stature, hirsutism, acne, and impaired fertility. Hormonal testing is important in making the diagnosis of 21-hydroxylase deficiency, yet genetic testing is crucial to secure the diagnosis. More than 100 mutations have been identified caused by gene conversions, large scale gene deletions, and de novo mutations, and novel mutations are continuously being identified. Genotype–phenotype non-concordance is observed in a significant number of patients.
Book Synopsis Genetic Steroid Disorders by : Nicole Reisch
Download or read book Genetic Steroid Disorders written by Nicole Reisch and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Genetic Steroid Disorders by : Phyllis W. Speiser
Download or read book Genetic Steroid Disorders written by Phyllis W. Speiser and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 opinion and consensus of the endocrine community, as reflected in The Endocrine Society’s 2010 Clinical Practice Guidelines for the treatment of CAH (J Clin Endocrinol Metab 95: 4133–60).
Book Synopsis Genetic Steroid Disorders by : Heino F.L. Meyer-Bahlburg
Download or read book Genetic Steroid Disorders written by Heino F.L. Meyer-Bahlburg and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Genetic Steroid Disorders by : Walter L. Miller
Download or read book Genetic Steroid Disorders written by Walter L. Miller and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 insufficiency and 46,XY disorders of sexual development (DSD). The lipoid CAH phenotype, including spontaneous puberty in 46,XX females, is explained by a two-hit model. StAR mutations that retain partial function cause milder non-classic disease characterized by glucocorticoid deficiency, with lesser disorders of mineralocorticoid and sex steroid synthesis. Rare P450scc mutations are clinically and hormonally indistinguishable from lipoid CAH, and may also present as milder non-classic disease. Adrenal imaging may distinguish these but is not 100% reliable, necessitating DNA sequencing.
Book Synopsis Genetic Steroid Disorders by : Felix Beuschlein
Download or read book Genetic Steroid Disorders written by Felix Beuschlein and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 an experimental system owing to the similarity to humans with respect to genome organization, development, and physiology. For the majority of adrenal genetic disorders, mouse models exist that in most instances resemble the clinical phenotype observed in affected patients. Here we provide an overview of these models that allows for both mechanistic and therapeutically relevant investigations that will eventually translate into improved patient care.
Book Synopsis Genetic Steroid Disorders by : David E. Reichman
Download or read book Genetic Steroid Disorders written by David E. Reichman and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 steroid enzyme deficiencies outlined.
Book Synopsis Genetic Steroid Disorders by : Perrin C. White
Download or read book Genetic Steroid Disorders written by Perrin C. White and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 steroid 11β-hydroxylase deficiency, a form of congenital adrenal hyperplasia. Mutations in CYP11B2 result in aldosterone synthase deficiency, which can cause hyponatremia, hyperkalemia and hypovolemia in infancy. These are both recessive disorders. Unequal crossing over between the CYP11B genes can generate a duplicated chimeric gene, causing glucocorticoid-suppressible hyperaldosteronism, an autosomal dominant form of hypertension. Frequent polymorphisms in these genes can affect aldosterone secretion and risk of hypertension.
Book Synopsis Genetic Steroid Disorders by : Christa E. Flück
Download or read book Genetic Steroid Disorders written by Christa E. Flück and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 activities of several steroid and drug metabolizing P450 proteins. Mutations in POR may have variable effects on different P450 partner proteins depending on the location of the mutation. The POR mutations that disrupt the binding of cofactors have a negative impact on all partner proteins, while mutations causing subtle structural changes may lead to altered interaction with partner proteins and the overall effect may be different for each partner.
Book Synopsis Genetic Steroid Disorders by : Charles Sultan
Download or read book Genetic Steroid Disorders written by Charles Sultan and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: After reviewing the mechanisms of androgen action, we will look at the main clinical features of androgen insensitivity, as well as the biological, cellular, and molecular tools used to investigate the AR. Numerous AR mutations have been described over the past 20 years. We will consider the challenges for diagnosis and prognosis by examining the genotype–phenotype relationship and the possibility of somatic mutations. Last, we will address the role of genetic counseling and the elements that should be taken into account for the difficult decision of sex assignment in children affected with AIS.
Book Synopsis Genetic Steroid Disorders by : Berenice B. Mendonca
Download or read book Genetic Steroid Disorders written by Berenice B. Mendonca and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: 17β-hydroxysteroid dehydrogenase 3 deficiency (17β-HSD3) consists of a defect in the last phase of steroidogenesis, in which androstenedione is converted into testosterone and estrone into estradiol. Patients present female-like or with ambiguous genitalia at birth and most affected males are raised as females. Virilization in subjects with 17β-HSD3 deficiency occurs at the time of puberty and almost half change to be males. Maintenance of the testes in patients raised male is safe and recommended, except when the testes cannot be positioned inside the scrotum. The phenotype of 46,XY disorders of sex development (DSD) owing to 17β-HSD3 deficiency is extremely variable and is clinically indistinguishable from other causes of 46,XY DSD such as partial androgen insensitivity syndrome and 5α-reductase 2 deficiency. Laboratory diagnosis is based on elevated serum levels of androstenedione and estrone and low levels of testosterone and estradiol, resulting in elevated androstenedione:testosterone and estrone:estradiol ratios, indicating an impairment of the conversion of 17-keto into 17-hydroxysteroids. The disorder is due to homozygous or compound heterozygous mutations in the HSD17B3 gene that encodes the 17β-HSD3 isoenzyme. Molecular genetic testing confirms the diagnosis and provides the orientation for genetic counseling. Our proposal in this article is to review the reported and our own cases of 17β-HSD3 deficiency.
Book Synopsis Genetic Steroid Disorders by : Mabel Yau
Download or read book Genetic Steroid Disorders written by Mabel Yau and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: Apparent mineralocorticoid excess (AME) is a rare inherited form of hypertension caused by 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD) deficiency. The disorder was first described biochemically and hormonally in 1977 by New et al. in a Native American girl with severe hypertension. AME defined an important “pre-receptor” pathway in steroid hormone action and their specificities to the receptor. The exploration of the pathogenesis of AME opened a new area in receptor biology as a result of the demonstration that the specificity of the mineralocorticoid receptor function depends on a metabolic enzyme (11β-HSD2) rather than the receptor itself. The clinical manifestations of AME mimic those of excessive mineralocorticoid activity, but plasma levels of aldosterone and other known mineralocorticoids are not elevated. Affected patients may present with low birthweight, failure to thrive, severe hypertension, hypercalciuria and renal failure. The hypertension is severe, with onset in early childhood.
Book Synopsis Genetic Steroid Disorders by : John W. Funder
Download or read book Genetic Steroid Disorders written by John W. Funder and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 to be prompt, vigorous, and appropriate in terms of rectifying electrolyte abnormalities and lowering blood pressure.
Book Synopsis Genetic Steroid Disorders by : Yves Morel
Download or read book Genetic Steroid Disorders written by Yves Morel and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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); females exhibit either normal sexual differentiation or mild virilization.
Book Synopsis Genetic Steroid Disorders by : Denesy Mancenido
Download or read book Genetic Steroid Disorders written by Denesy Mancenido and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: Congenital adrenal hyperplasia (CAH) owing to 21-hydroxylase deficiency (21OHD) is a disorder of adrenal steroidogenesis, which causes virilization of external genitalia in females affected with the severe form of the disease. However, genital ambiguity is preventable with prenatal treatment with dexamethasone during the first trimester. While prenatal treatment has remained largely unchanged since its institution, prenatal diagnosis of CAH has witnessed a number of advancements in the past 50 years. The first successful prenatal diagnosis utilized hormonal measurements of the amniotic fluid. Elevated levels of 17α-hydroxyprogesterone in the amniotic fluid became diagnostic for a fetus affected with the severe form of the disorder. This finding was followed by the discovery of the close linkage between the disease and the HLA complex, which led to HLA linkage studies as a second approach for prenatal diagnosis. Cloning of the CYP21A2 gene ushered in molecular genetic analysis as the third method for prenatal diagnosis. Using polymerase chain reaction (PCR)-based methods to amplify the CYP21A2 active gene, and not the CYP21A1P pseudogene, diagnostic procedures increased in specificity and led to accurate prenatal diagnosis in the first trimester. The advent of non-invasive prenatal diagnosis heralds a new development for prenatal diagnosis of CAH, with the potential for improved safety, earlier detection, and increased accessibility.
Book Synopsis Genetic Steroid Disorders by : Hayk Barseghyan
Download or read book Genetic Steroid Disorders written by Hayk Barseghyan and published by Elsevier Inc. Chapters. This book was released on 2013-08-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ovotesticular DSDs (OT-DSDs) are disorders of sex development in which both testicular and ovarian tissues are present in the same individual. We review the phenotypic variability of OT-DSDs, their sex chromosome constitution, and their molecular genetics, which remain for most patients, poorly understood.
