Congenital Adrenal Hyperplasia
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Seminar Congenital adrenal hyperplasia Diala El-Maouche, Wiebke Arlt, Deborah P Merke Lancet 2017; 390: 2194–210 Congenital adrenal hyperplasia is a group of autosomal recessive disorders encompassing enzyme deficiencies in the Published Online adrenal steroidogenesis pathway that lead to impaired cortisol biosynthesis. Depending on the type and severity of May 30, 2017 steroid block, patients can have various alterations in glucocorticoid, mineralocorticoid, and sex steroid production that http://dx.doi.org/10.1016/ require hormone replacement therapy. Presentations vary from neonatal salt wasting and atypical genitalia, to adult S0140-6736(17)31431-9 presentation of hirsutism and irregular menses. Screening of neonates with elevated 17-hydroxyprogesterone This online publication has been corrected. The corrected concentrations for classic (severe) 21-hydroxylase deficiency, the most common type of congenital adrenal hyperplasia, version first appeared at is in place in many countries, however cosyntropin stimulation testing might be needed to confirm the diagnosis or thelancet.com on Nov 11, 2017 establish non-classic (milder) subtypes. Challenges in the treatment of congenital adrenal hyperplasia include avoidance National Institutes of Health of glucocorticoid overtreatment and control of sex hormone imbalances. Long-term complications include abnormal Clinical Center, Bethesda, growth and development, adverse effects on bone and the cardiovascular system, and infertility. Novel treatments aim MD 20892, USA (D El-Maouche MD, to reduce glucocorticoid exposure, improve excess hormone control, and mimic physiological hormone patterns. Prof D P Merke MD); Institute of Metabolism and Systems Introduction More than 95% of congenital adrenal hyperplasia cases Research (IMSR), University of In 1865, Luigi De Crecchio, an Italian pathologist, are due to 21OH deficiency,23 characterised by impaired Birmingham & Centre for Endocrinology, Diabetes and described the case of a man who, at autopsy, was found to cortisol and aldosterone production and androgen excess. Metabolism (CEDAM), have female internal anatomy and large adrenal glands, Life-saving neonatal screening for classic congenital Birmingham Health Partners, representing the first known case of presumed congenital adrenal hyperplasia due to 21OH deficiency was first Birmingham, UK adrenal hyperplasia (figure 1).1 However, treatment for done in Alaska in 1977,7 and is currently used worldwide (Prof W Arlt MD); and The Eunice Kennedy Shriver congenital adrenal hyperplasia was not introduced in more than 40 countries, including all 50 US states National Institute of Child for almost another century when cortisone was given for since 2009, although it is yet to be implemented in the Health and Human what was then known as adrenogenital syndrome.18–22 UK.7,23–25 Although all types of classic congenital adrenal Development, Bethesda, MD, Congenital adrenal hyperplasia is a group of seven hyperplasia are rare orphan diseases, the non-classic USA (Prof D P Merke) autosomal recessive diseases caused by mutations in form due to 21OH deficiency is estimated to be one of the Correspondence to: 26,27 Dr Deborah P Merke, National genes encoding enzymes in pathways involved in cortisol most common autosomal recessive disorders. Institutes of Health Clinical biosynthesis: 21-hydroxylase (21OH), 11β-hydroxylase Congenital adrenal hyperplasia remains one of the Center, Bethesda, (11βOH), 17α-hydroxylase (17OH; also known as most challenging endocrine disorders to diagnose, MD 20892–1932, USA 17,20-lyase), 3β-hydroxysteroid dehydrogenase type 2 manage, and treat because of the disorders’ direct and [email protected] (3βHSD2), steroidogenic acute regulatory protein (StAR), indirect effects on steroidogenic pathways and the rarity P450 cholesterol side-chain cleavage enzyme (SCC), and of these conditions. Advances in genetics, metabolomics, P450 oxidoreductase (POR). Multiple hormonal and treatment strategies continue to improve imbalances occur and congenital adrenal hyperplasia understanding of these complex diseases and aim to manifests with a range of clinical and biochemical improve patient outcomes. phenotypes, with or without alterations in glucocorticoid, mineralocorticoid, and sex steroid production. Both Genetics and pathophysiology severe (classic) and mild (non-classic) forms of congenital Overview adrenal hyperplasia have been described. All types of congenital adrenal hyperplasia are monogenetic and autosomal recessive. Most patients are compound heterozygotes, meaning that they have different mutations Search strategy in two alleles for a particular gene. The clinical We searched the Cochrane Library, MEDLINE, and Embase between Jan 1, 2010, and manifestation follows the allele that results in a more Sept 30, 2016. Keywords and controlled vocabulary and their synonyms were used when functional enzyme, and generally genotype–phenotype 28,29 appropriate. We used variations of the search term “congenital adrenal hyperplasia” in correlation is good. combination with the terms “diagnosis/diagnostics”, “genetics”, “genomics”, “adrenal Adrenal steroidogenesis occurs by a series of steps crisis”, “glucocorticoid”, “mineralocorticoid”, “gene therapy”, “quality of life”, “well-being”, facilitated by adrenal zone-specific enzyme expression, “screening”, “metabolomics”, “prenatal”, “antenatal”, “bone mineral density”, “tumor”, and in different types of congenital adrenal hyperplasia “pregnancy”, “treatment/therapy/ therapeutic”, “fertility/fecundity”, “surgery”, this process is interrupted at distinct points. In addition “management”, “metabolic”, and “complications”. We largely selected publications in the to the classic well established steroidogenesis pathway, past 5 years, but did not exclude commonly referenced and highly regarded older an alternative pathway to active androgen biosynthesis 30,31 publications. We also searched the reference lists of articles identified by this search exists (termed the backdoor pathway), which might strategy and selected those we judged relevant. Review articles and book chapters are play a role in the pathophysiology of congenital adrenal cited to provide readers with more details and more references than this Seminar has hyperplasia (figure 2). The clinical manifestation of room for. The search was restricted to English publications. congenital adrenal hyperplasia is closely related to the type and severity of impairment. 2194 www.thelancet.com Vol 390 November 11, 2017 þÿDownloaded for Anonymous User (n/a) at Consejería de Sanidad de Madrid Biblioteca Virtual from ClinicalKey.com by Elsevier on February 21, 2019. For personal use only. No other uses without permission. Copyright ©2019. Elsevier Inc. All rights reserved. Seminar 1985: CAH caused by CYPA gene mutations9 1985: CAH caused by 2010 onwards: 1950: Nobel Prize for multiple abnormalities 2001: CAH Genetic advances, 1865: Case report of “discoveries relating of microsomal mixed- caused by biomarker a man with internal to the hormones of function oxidases (later CYPA gene discovery, and female anatomy, the adrenal cortex, 1962: Lipoid known as POR deficiency)10 mutations15 novel treatments hypospadias, enlarged their structure and CAH described5 adrenals, and sudden biological effects”2 1962: CAH 1977: First 1992: CAH caused death1 1950: Cortisone caused by defect neonatal screen by HSDB gene treatment for CAH in 3βHSD26 in Alaska8 mutations13 1800s 1930 1940 1950 1960 1970 1980 1990 2000 2010 1930s: Chemical 1955: CAH 1966: CAH caused 1988: CAH 1995: CAH structure of caused by defect by defect in caused by caused by adrenal steroids in 21-hydroxylation 17α-hydroxylation7 CYPA gene StAR gene and 11-hydroxylation3,4 mutations11 mutations14 1940s: 1991: CAH 2004: CAH Conceptualisation of HPA axis, caused by caused by cortisone treatment for CYPB gene POR gene rheumatoid arthritis (1949) mutations12 mutations16,17 Figure 1: Timeline of important discoveries in adrenal steroidogenesis, treatment landmarks, and gene discovery of congenital adrenal hyperplasia HPA=hypothalamic-pituitary-adrenal. CAH=congenital adrenal hyperplasia. 3βHSD2=3β-hydroxysteroid dehydrogenase type 2 deficiency. POR=P450 oxidoreductase. 21OH deficiency skeletal growth in children. Patients with the non- The gene for 21OH, CYP21A2, is located within the classic form retain up to 50% of enzyme activity and human leucocyte antigen class III region of mostly do not have adrenal insufficiency, but might chromosome 6 (table 1). CYP21A2 and a homologous have partial glucocorticoid deficiency, and female pseudogene, CYP21A1P, lie about 30 kb apart. Meiotic patients have normal genitalia.41 Patients might recombination events are common in this genomic present with mild androgen excess or have few or region because of the high degree of sequence homology no symptoms. In fact, the term cryptic congenital between duplicated genes. Approximately 95% of adrenal hyperplasia was created to define patients with CYP21A2 disease causing mutations are CYP21A1P- non-classic congenital adrenal hyperplasia who are derived variants or deletions due to recombination identified by family genetic studies, but are otherwise events.28,39 asymptomatic.42 Defective 21OH-hydroxylation results in decreased glucocorticoid and mineralocorticoid synthesis and 11βOH deficiency elevated precursors, most notably 17-hydroxyprogesterone Congenital adrenal hyperplasia caused by 11βOH (17OHP), which is used for congenital adrenal deficiency is due to CYP11B1 mutations