P450c17 deficiency: clinical and molecular characterization of six patients

CYP17A1 Pathogenic Variants in 26 Chinese Patients With 17α-Hydroxylase Deficiency by Targeted Long-Read Sequencing

BACKGROUND

17α-hydroxylase/17,20-lyase deficiency (17-OHD) is a rare subtype of congenital adrenal hyperplasia caused by homozygous or compound heterozygous pathogenic variants in the CYP17A1 gene.

PURPOSE

This study aimed to identify and characterize pathogenic variants in individuals with 17-OHD and to classify and validate the pathogenicity of novel variants.

METHODS

Variants were identified via targeted long-read sequencing (TLRS) of the entire CYP17A1 gene in enrolled 17-OHD patients. The American College of Medical Genetics and Genomics (ACMG) guidelines were employed to assess the pathogenicity of novel variants. Minigene splicing assays were utilized to determine the impact of variants on RNA splicing.

RESULTS

This study encompassed 26 patients with 17-OHD, detecting 2 trans pathogenic variants per patient using the TLRS method. A total of 20 pathogenic variants in the CYP17A1 were identified, with variant c.985_987delinsAA being the most frequent (28/52 alleles), followed by variant c.1459_1467del (4/52 alleles). Five novel variants including c.280T > C, c.470T > A, c.636_637del, c.866A > G, and c.1095del, were classified as pathogenic/likely pathogenic ones according to ACMG criteria. The minigene splicing assays revealed c.866A > G in exon 5 causes a frameshift due to a 104 base pair deletion, while c.470T > A generates 2 transcripts, with the vast majority spliced like the wild-type and a small fraction lacking 35 base pairs in the 5' flank of exon 3.

CONCLUSION

The TLRS can determine the cis/trans orientation of 2 distant variants. Five novel pathogenic variants were reported, broadening the spectrum of the CYP17A1 pathogenic variants. The variant c.866A > G, located deep in the exon, affects gene function through mechanisms of aberrant splicing.

Congenital Adrenal Hyperplasia with Combined 21-hydroxylase deficiency and 17α-hydroxylase/17,20-lyase deficiency: An undervirilized male

21-hydroxylase deficiency stands as the most prevalent form of congenital adrenal hyperplasia, primarily resulting from mutations in the CYP21A2 gene. On the other hand, mutations within the CYP17A1 gene lead to 17α-hydroxylase/17,20-lyase enzyme deficiencies. The scarcity of 17-OH deficiency is noteworthy, accounting for less than 1% of all congenital adrenal hyperplasia cases. The male patient, born from a first-degree cousin marriage, exhibited several symptoms, including left undescended testis, micropenis, penile chord, left sensorineural hearing loss, and gynecomastia. He reported micropenis as a concern at the age of 13.5 years. His hormone profile revealed high levels of serum 17-hydroxyprogesterone, progesterone, and pregnenolone. In this case with a 46 XY karyotype, suspicions arose regarding Cytochrome P450 oxidoreductase deficiency due to ambiguous genitalia and an atypical hormone profile. Analysis unveiled two distinct homozygous and pathogenic variants in the CYP21A2 and CYP17A1 genes. Notably, mineralocorticoid precursors escalated, while cortisol and sex steroid precursors decreased during the high (250 mcg) dose ACTH stimulation test. The mutation c.1169C > G (p.Thr390Arg) in CYP17A1, which is the second documented case in literature, stands out due to its unique set of accompanying features. Mutations occurring in CYP21A2 and CYP17A1 result in complete or partial enzyme deficiencies, and the detection of homozygous mutations in two different enzyme systems within the steroidogenic pathway is noteworthy.

Primary Adrenal Insufficiency in Childhood: Data From a Large Nationwide Cohort

CONTEXT

Primary adrenal insufficiency (PAI) is a rare and potentially life-threatening condition that is poorly characterized in children.

OBJECTIVE

To describe causes, presentation, auxological outcome, frequency of adrenal crisis and mortality of a large cohort of children with PAI.

PATIENTS AND METHODS

Data from 803 patients from 8 centers of Pediatric Endocrinology were retrospectively collected.

RESULTS

The following etiologies were reported: 85% (n = 682) congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD); 3.1% (n = 25) X-linked adrenoleukodystrophy; 3.1% (n = 25) autoimmune polyglandular syndrome type 1; 2.5% (n = 20) autoimmune adrenal insufficiency; 2% (n = 16) adrenal hypoplasia congenital; 1.2% (n = 10) non-21-OHD CAH; 1% (n = 8) rare syndromes; 0.6% (n = 5) familial glucocorticoid deficiency; 0.4% (n = 3) acquired adrenal insufficiency; 9 patients (1%) did not receive diagnosis. Since 21-OHD CAH has been extensively characterized, it was not further reviewed. In 121 patients with a diagnosis other than 21-OHD CAH, the most frequent symptoms at diagnosis were fatigue (67%), hyperpigmentation (50.4%), dehydration (33%), and hypotension (31%). Elevated adrenocorticotropic hormone (96.4%) was the most common laboratory finding followed by hyponatremia (55%), hyperkalemia (32.7%), and hypoglycemia (33.7%). The median age at presentation was 6.5 ± 5.1 years (0.1-17.8 years) and the mean duration of symptoms before diagnosis was 5.6 ± 11.6 months (0-56 months) depending on etiology. Rate of adrenal crisis was 2.7 per 100 patient-years. Three patients died from the underlying disease. Adult height, evaluated in 70 patients, was -0.70 ± 1.20 standard deviation score.

CONCLUSIONS

We characterized one of the largest cohorts of children with PAI aiming to improve the knowledge on diagnosis of this rare condition.

Clinical, biochemical and genetic characteristics of children with congenital adrenal hyperplasia due to 17α-hydroxylase deficiency

Objectives Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder, that could rarely be due to 17 α-hydroxylase deficiency (17αOHD) and/or 17,20 lyase deficiency. Mutation of CYP17A1 gene causes deficiency of glucocorticoids and androgens but excess of mineralocorticoids. Lack of genital ambiguity in most children causes a delay in diagnosis even until puberty. Classical presentation with hypertension and hypokalemia is often not encountered. We intended to study the clinical, biochemical and genetic characteristics of children diagnosed with CAH due to 17αOHD. Methods Three children who were diagnosed with CAH due to 17αOHD in our institute and on follow up were included in this retrospective study. Clinical, biochemical and genetic characteristics of these children were retrieved and studied from electronic medical records. Results Two children were genetic females and one was genetic male, but all three were raised as females. All had hypertension at diagnosis except one but none had hypokalemia. All of them had mutation in the CYP17A1 gene. The two females responded well to oestrogen and progesterone and had adequate estrogenization clinically. Conclusions Even though CAH due to 17αOHD is quite rare, it should be considered while evaluating young individuals with hypogonadism, hypertension with or without hypokalemia. Lack of genital ambiguity and absence of classical signs at presentation does not rule out this not so uncommon condition and warrants follow up.

Partial deficiency of 17α-hydroxylase: a rare cause of congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) due to 17α-hydroxylase deficiency, a rare CAH syndrome, is characterised by failure to synthetise cortisol, adrenal androgens and gonadal steroids. The partial deficiency is much rarer, presenting with subtler symptoms. Failure to reach a proper diagnosis causes inappropriate hypertension treatment and impairs the development of secondary sexual characteristics. We report a case of a 30-year-old woman transferred to an endocrinology clinic for evaluation of autoimmune thyroiditis. She was started on oral contraceptives at the age of 13 due to oligomenorrhea and presented underdeveloped pubic and axillar hair and Tanner stage 3 breast development. Biochemical tests evidenced very low androgens levels and genetic analysis confirmed a CAH due to 17α-hydroxylase deficiency. Partial 17α-hydroxylase deficiency is a rare clinical entity, nevertheless, it should be included in the differential diagnosis of menstrual disorders.

MECHANISMS IN ENDOCRINOLOGY: Rare defects in adrenal steroidogenesis

Congenital adrenal hyperplasia (CAH) is a group of genetic disorders of adrenal steroidogenesis that impair cortisol synthesis, with compensatory increases in ACTH leading to hyperplastic adrenals. The term 'CAH' is generally used to mean 'steroid 21-hydroxylase deficiency' (21OHD) as 21OHD accounts for about 95% of CAH in most populations; the incidences of the rare forms of CAH vary with ethnicity and geography. These forms of CAH are easily understood on the basis of the biochemistry of steroidogenesis. Defects in the steroidogenic acute regulatory protein, StAR, disrupt all steroidogenesis and are the second-most common form of CAH in Japan and Korea; very rare defects in the cholesterol side-chain cleavage enzyme, P450scc, are clinically indistinguishable from StAR defects. Defects in 3β-hydroxysteroid dehydrogenase, which also causes disordered sexual development, were once thought to be fairly common, but genetic analyses show that steroid measurements are generally unreliable for this disorder. Defects in 17-hydroxylase/17,20-lyase ablate synthesis of sex steroids and also cause mineralocorticoid hypertension; these are common in Brazil and in China. Isolated 17,20-lyase deficiency can be caused by rare mutations in at least three different proteins. P450 oxidoreductase (POR) is a co-factor used by 21-hydroxylase, 17-hydroxylase/17,20-lyase and aromatase; various POR defects, found in different populations, affect these enzymes differently. 11-Hydroxylase deficiency is the second-most common form of CAH in European populations but the retention of aldosterone synthesis distinguishes it from 21OHD. Aldosterone synthase deficiency is a rare salt-losing disorder. Mild, 'non-classic' defects in all of these factors have been described. Both the severe and non-classic disorders can be treated if recognized.

The Glu331del mutation in the CYP17A1 gene causes atypical congenital adrenal hyperplasia in a 46,XX female

17α-Hydroxylase deficiency is an uncommon type of congenital adrenal hyperplasia (CAH) caused by mutations in the CYP17A1 gene encoding both 17α-hydroxylase and 17,20-lyase, essential for sex steroids production. Main clinical features include lack of pubertal development, hypertension, and hypokalemia. We report the first case of a 46,XX female homozygote for the p.Glu331del mutation in the CYP17A1 gene showing an atypical clinical presentation. She was evaluated the first time for primary amenorrhea and delayed puberty in the presence of low levels of androgens, 17β-estradiol, serum cortisol, and high levels of progesterone and gonadotropins. After puberty, the patient did not show hypocortisolism and/or hypertension. She started estrogen therapy for pubertal induction, followed by ethinylestradiol/gestodene with clinical and biochemical stability during the follow-up period. At the age of 40 years, she developed hypokalemia and clinical signs of hypocortisolism. Oral corticosteroid treatment was started showing a prompt clinical improvement. Modeling analysis predicted the main outcome of the E331 deletion to impair cytochrome b5 binding, according to a major effect on the enzyme's lyase activity. These data broaden the molecular and clinical spectrum of CAH caused by 17α-hydroxylase deficiency and adds to current genotype-phenotype correlations.

17α-HYDROXYLASE DEFICIENCY IS AN UNDERDIAGNOSED DISEASE: HIGH FREQUENCY OF MISDIAGNOSES IN A LARGE COHORT OF BRAZILIAN PATIENTS

OBJECTIVE

17α-Hydroxylase deficiency (P450c17D) is characterized by hypogonadism and mineralocorticoid hypertension. We aimed to estimate the relative incidence and spectrum of preliminary misdiagnoses in Brazilian P450c17D patients.

METHODS

In this cross-sectional study, we reviewed, updated, and analyzed data of 40 P450c17D patients (21 XY, 19 XX).

RESULTS

Complete data were unavailable for 2 patients. Seven patients were relatives of an index case. Of the 31 index cases, 29 (94%) received a total of 16 misdiagnoses (1-4 per patient) before confirmation of P450c17D. Essential hypertension (55%), pure gonadal dysgenesis (35%), and androgen resistance syndrome (21%) were the most frequent misdiagnoses. Median ages at initial and final diagnosis were 13.2 and 16.5 years, respectively, with an average interval to diagnosis of 3.2 years. Initially, 38 (95%) patients had hypertension, and 75% had hypokalemia. Primary amenorrhea and sexual infantilism were present in 95% patients, and 73% were at Tanner stage I. All had low-to-undetectable estrogens and androgens with elevated gonadotropins and progesterone (580 ± 53 ng/dL). Several had recurrent infections in childhood and neurological issues prior to final diagnosis and/or had siblings who died of infectious diseases or unknown causes before puberty.

CONCLUSION

The high percentage of prior misdiagnoses in P450c17D patients may be attributable to the rarity of and relative unfamiliarity with the disease, its varied clinical presentation, and the limited access to critical steroid dosages and genotyping. Reduced sex steroids, and elevated gonadotropins and progesterone levels, in addition to mineralocorticoid hypertension, are pathognomonic of P450c17D. CYP17A1 gene mutations provide a definitive diagnosis.

ABBREVIATIONS

ACTH = adrenocorticotropic hormone CAH = congenital adrenal hyperplasia CYP17A1 = 17α-hydroxylase enzyme DOC = deoxycorticosterone HH = hypergonadotropic hypogonadism P450c17D = 17α-hydroxylase deficiency TS = Tanner stage.

Monogenic Hypertension in Children: A Review With Emphasis on Genetics

Hypertension (HT) is a public health problem in children particularly related to the epidemic of overweight and obesity. Monogenic forms of HT are important in the differential diagnosis in children presenting with severe or refractory HT, who have a family history of early-onset HT, unusual physical examination findings, and/or characteristic hormonal and biochemical abnormalities. Most genetic defects in these disorders ultimately result in increased sodium transport in the distal nephron resulting in volume expansion and HT. Genetic testing, which is increasingly available, has diagnostic, therapeutic, and predictive implications for families affected by these rare conditions.

New, recurrent, and prevalent mutations: Clinical and molecular characterization of 26 Chinese patients with 17alpha-hydroxylase/17,20-lyase deficiency

BACKGROUND

Combined 17alpha-hydroxylase/17,20-lyase deficiency (17OHD), caused by mutations in the CYP17A1 gene, is a rare autosomal recessive form of congenital adrenal hyperplasia and characterized by hyporeninemic hypokalemic hypertension, primary amenorrhea and absence of secondary sexual characteristics.

SUBJECTS AND METHODS

Twenty six 17OHD subjects from 23 Chinese families were recruited. The CYP17A1 gene was sequenced and 17alpha-hydroxylase/17,20-lyase enzymatic activities were assessed in vitro.

RESULTS

Eight CYP17A1 mutations were identified in 23 patients. Of eight mutations, c.985_987delinsAA/p.Y329Kfs and c.1460_1469del/p.D487_F489del mutations accounted for 60.8% (28/46) and 21.7% (10/46) of the mutant alleles, respectively. The enzymatic activities for both mutations were completely abolished. We also identified three novel mutations c.971_972insG/p.K325Afx, c.1464_1466delT/p.F489Sfx and c.1386G>T/p.R462S. The enzymatic activities for c.971_972insG/p.K325Afx and c.1464_1466delT/p.F489Sfx mutations were almost completely abolished, whereas the mutation c.1386G>T/p.R462S only resulted in partial reduction of 17alpha-hydroxylase (34.6%) and 17,20 lyase activities (27.0%), which is correlated with the partial 17OHD phenotype in this patient.

CONCLUSION

The c.985_987delinsAA/p.Y329Kfs and c.1460_1469del/p.D487_F489del mutations are prevalent in Chinese 17OHD patients. The genetic defects are well correlated with the phenotypes in both complete and partial forms of 17OHD.

Identification of a novel large CYP17A1 deletion by MLPA analysis in a family with classic 17α-hydroxylase deficiency

Steroid 17α-hydroxylase deficiency (17OHD) is a rare form of congenital adrenal hyperplasia caused by mutations in the 17α-hydroxylase ( CYP17A1) gene. CYP17A1 is a key enzyme in the biosynthesis of adrenal and gonadal steroid hormones facilitating both 17α-hydroxylase and 17,20-lyase activities. We characterized a partial CYP17A1 deletion in a Kurdish family with 17OHD by multiplex ligation-dependent probe amplification (MLPA). The index patient presented with amenorrhea and lack of pubertal development. Investigations established the diagnosis of 46,XY disorder of sex development (DSD). She is the daughter of consanguineous parents and has 2 sisters with similar clinical presentation. All patients showed biochemical signs of primary adrenal and gonadal insufficiency. The molecular genetic analysis by PCR suggested a deletion spanning exons 1–6 of the CYP17A1 gene. MLPA analysis confirmed the large partial CYP17A1 deletion in patients and parents in homozygous and heterozygous state, respectively. This is the first report employing MLPA for mutation analysis to detect a deletion of CYP17A1 spanning multiple exons in 3 patients with classic 17OHD. Therefore, it is important to consider large partial CYP17A1 deletions in 17OHD in addition to point mutations in cases where no segregation analysis is possible to determine the correct genotype.

17α-hydroxylase deficiency diagnosed in early infancy caused by a novel mutation of the CYP17A1 gene

BACKGROUND

Mutations of the CYP17A1 gene cause 17α-hydroxylase deficiency (17OHD) resulting in 46,XY disorder of sex development, hypertension, hypokalemia and absent pubertal development. It is a rare, autosomal recessive form of congenital adrenal hyperplasia (CAH).

PATIENT

We report on a neonate with prenatally determined 46,XY karyotype. At 20 weeks of gestation, lack of development of male external genitalia was noticed. A phenotypically female child was born at 41 weeks of gestation.

RESULTS

Postnatal ultrasound revealed testes in both labia majora, an absence of uterus and normal adrenal glands. Steroid hormone analysis in serum revealed low basal levels of cortisol, testosterone and androstenedione in the presence of massively elevated corticosterone at the age of 2 weeks. The urinary steroid profile from spot urine showed excessive excretion of 17-desoxysteroids, decreased glucocorticoid metabolites and absent C19 steroids, thus proving 17OHD. Molecular analysis identified a novel mutation of the CYP17A1 gene: c.896T>A (p.I299N) in exon 5. Substitution with hydrocortisone was started. The child is raised as a girl and is developing well so far.

CONCLUSION

Herein, we report the unusually early diagnosis of a newborn with the rare CAH form of 17OHD allowing an early start of treatment.

Neurobiology of DHEA and effects on sexuality, mood and cognition

Dehydroepiandrosterone (DHEA) and its sulfate ester, DHEAS, are the most abundant steroid hormones in the humans. However, their physiological significance, their mechanisms of action and their possible roles as treatment are not fully clarified. Biological actions of DHEA(S) in the brain involve neuroprotection, neurite growth, neurogenesis and neuronal survival, apoptosis, catecholamine synthesis and secretion, as well as anti-oxidant, anti-inflammatory and antiglucocorticoid effects. In addition, DHEA affects neurosteroidogenis and endorphin synthesis/release. We also demonstrated in a model of ovariectomized rats that DHEA therapy increases proceptive behaviors, already after 1 week of treatment, affecting central function of sexual drive. In women, the analyses of clinical outcomes are far from being conclusive and many issues should still be addressed. Although DHEA preparations have been available in the market since the 1990s, there are very few definitive reports on the biological functions of this steroid. We demonstrate that 1 year DHEA administration at the dose of 10mg provided a significant improvement in comparison with vitamin D in sexual function and in frequency of sexual intercourse in early postmenopausal women. Among symptomatic women, the spectrum of symptoms responding to DHEA requires further investigation, to define the type of sexual symptoms (e.g. decreased sexual function or hypoactive sexual desire disorder) and the degree of mood/cognitive symptoms that could be responsive to hormonal treatment. In this regard, our findings are promising, although they need further exploration with a larger and more representative sample size. This article is part of a Special Issue entitled: Essential role of DHEA.

CYP17A1 gene mutations and hypertension variations found in 46, XY females with combined 17α-hydroxylase/17, 20-lyase deficiency

The aim of this study was to analyze the structural consequences of the mutations in CYP17A1 gene and their relationship with the variations of clinical manifestations in three patients who presented with complete or partial combined 17α-hydroxylase/17,20-lyase deficiency (17OHD). DNA sequences of the coding exons and intron/exon boundaries of the CYP17A1 gene were analyzed for mutations. In silico analysis with computational three-dimensional model of human P450c17 and multiple alignments analysis were performed to evaluate the spatial conformational changes by missense mutations. Five mutations p.S117fs (c.351_352delCT), p.H373L (c.1184 A>T), p.Y329fs (c.985_987delTACinsAA), p.A82D (c.245 C>A) and p.L209P (c.626 T>C) were identified in three patients, respectively. The novel mutation p.S117fs (c.351_352delCT) has not been reported previously. In silico analysis explained the conformational changes by the described mutations, which resulted in different severe 17OHD. Our studies also suggest that molecular data accompanying with in silico analysis of the CYP17A1 gene are much helpful for the diagnosis, management and genetic counseling of 17OHD.

A review of the literature on common CYP17A1 mutations in adults with 17-hydroxylase/17,20-lyase deficiency, a case series of such mutations among Koreans and functional characteristics of a novel mutation

OBJECTIVE

17α-hydroxylase/17,20-lyase deficiency is a rare form of congenital adrenal hyperplasia, characterized by hypertension and sexual infantilism and caused by loss-of-function mutations in CYP17A1. This study investigated the clinical and molecular characteristics of six adults with 17α-hydroxylase/17,20-lyase deficiency and the functional consequences of a novel CYP17A1 mutation.

MATERIALS AND METHODS

Six phenotypic females, three with 46,XY and three with 46,XX karyotypes, presented with primary amenorrhea and hypertension. All had elevated levels of plasma adrenocorticotropic hormone, serum gonadotropin, progesterone, and 11-deoxycorticosterone, and reduced testosterone and dehydroepiandrosterone sulfate (DHEA-S). All coding exons and flanking intronic sequences of CYP17A1 were directly sequenced using genomic DNA. Wild-type and mutant CYP17A1 cDNAs were inserted into the pcDNA3.1/V5-His-P450c17 vector, and transiently expressed in COS-7 cells. This was followed by an assessment of 17α-hydroxylase and 17,20-lyase activities by measuring the conversions of progesterone to 17-hydroxyprogesterone and 17-hydroxypregnenolone to DHEA.

RESULTS

The mutation analysis identified one patient with compound heterozygosity for p.H373L and p.W406L, one with compound heterozygosity for p.H373L and p.A174E, three with compound heterozygosity for p.Y329fs and p.H373L, and one with homozygosity for p.H373L. An in vitro functional analysis of the novel p.W406L mutation revealed a complete loss of 17α-hydroxylase/17, 20-lyase activities.

CONCLUSIONS

p.H373L was the most common mutation among these Korean patients, consistent with the high allele frequency of p.H373L in Chinese and Japanese populations, suggesting possible founder effects in Asian countries. The novel p.W406L mutation caused a complete loss of both catalytic activities, indicating that this amino acid is critical for P450c17 function.

Clinical and genetic analyses of a Chinese female with 17α-hydroxylase/17,20-lyase deficiency

AIMS

17α-Hydroxylase/17,20-lyase deficiency (17OHD) is a rare autosomal recessive disease caused by CYP17 gene mutations. This disease is clinically characterised by hypertension, hypokalaemia, sexual infantilism in females or pseudohermaphroditism in males, and adrenal hyperplasia. This study aims to investigate a rare case of 17OHD accompanied by both cystic ovaries and massive adrenal mass.

METHODS

This study performed clinical, hormonal, radiological and genetic analyses. Blood samples were collected from the patient for the genetic test. Genomic DNA was extracted from peripheral blood leukocytes, and the coding sequence abnormalities of CYP17 were assessed using polymerase chain reaction and direct sequencing analysis.

RESULTS

The genetic analysis of CYP17 revealed compound heterozygous mutations in the individual. One was a mis-sense mutation of c.1226 C > G, which changes codon 409 in exon 7 from proline (CCG) to arginine (CGG). Another was a mutation of p.Val311Asp,fs,330X, which was first reported in a compound heterozygote mutation of Y329fs and V311fs from a Chinese patient.

CONCLUSION

This study presented a rare case of 17OHD accompanied by both cystic ovaries and massive adrenal mass. This study obtained significant information on the genotype-phenotype correlation of 17OHD.

CYP17A1 mutations identified in 17 Chinese patients with 17α-hydroxylase/17,20-lyase deficiency

CONTEXT

17α-hydroxylase deficiency (17OHD) is a relatively rare disease, accounting for about 1% of congenital adrenal hyperplasia cases. The CYP17A1 gene mutation can lead to this disease. Human CYP17A1 gene is located on chromosome 10q24.3. It consists of eight exons encoding 508 amino acids. To date, more than 50 mutations in exons and introns of the CYP17A1 gene have been reported to cause complete or partial 17OHD.

OBJECTIVE

The aim of this study was to investigate the CYP17A1 gene mutation types in 17 Chinese patients, containing 11 complete and six partial 17OHD patients.

SETTING

We conducted the study in the Department of Obstetrics and Gynecology of Peking Union Medical College Hospital.

PATIENTS

Seventeen patients were studied with complete or partial 17OHD.

MAIN OUTCOME MEASURES

The CYP17A1 gene was sequenced and we measured steroid and sex hormone levels.

RESULTS

Analysis of the CYP17A1 gene in our patients revealed 12 different kinds of mutation. Two mutations (IVS1-1G>A and L209P) were novel mutations. Mutation c.985_987delTACinsAA (Y329KfsX418) in Exon 6 was the most common mutation in Chinese patients, accounting for 50 percents of the mutant alleles (17/34). Exon 6 was the hot spot since most mutations were detected in this exon (59%, 20/34 alleles). There was no mutation detected in the Exons 4 and 5.

Blood pressure and human genetic variation in the general population

PURPOSE OF REVIEW

Hypertension is a complex trait with multiple environmental and genetic contributors. Until recently, linkage studies of rare Mendelian disorders of hypertension and hypotension have produced the most notable progress toward understanding the heritable basis of blood pressure (BP). Association studies to identify common variants have been limited in the past by small sample sizes and most findings have lacked replication.

RECENT FINDINGS

Recently, well powered, targeted candidate gene and genome-wide association studies have reported reproducible associations between rare and common genetic variants and BP and hypertension at the population level.

SUMMARY

Identification of novel genes will lead to an improved understanding of BP regulation and the potential for novel therapies.

46,XX DSD and Antley-Bixler syndrome due to novel mutations in the cytochrome P450 oxidoreductase gene

Deficiency of the enzyme P450 oxidoreductase is a rare form of congenital adrenal hyperplasia with characteristics of combined and partial impairments in steroidogenic enzyme activities, as P450 oxidoreductase transfers electrons to CYP21A2, CYP17A1, and CYP19A1. It results in disorders of sex development and skeletal malformations similar to Antley-Bixley syndrome. We report the case of a 9-year-old girl who was born with virilized genitalia (Prader stage V), absence of palpable gonads, 46,XX karyotype, and hypergonadotropic hypogonadism. During the first year of life, ovarian cyst, partial adrenal insufficiency, and osteoarticular changes, such as mild craniosynostosis, carpal and tarsal synostosis, and limited forearm pronosupination were observed. Her mother presented severe virilization during pregnancy. The molecular analysis of P450 oxidoreductase gene revealed compound heterozygosis for the nonsense p.Arg223*, and the novel missense p.Met408Lys, inherited from the father and the mother, respectively. Arq Bras Endocrinol Metab. 2012;56(8):578-85

Mineralocorticoid hypertension

Hypertension affects about 10 - 25% of the population and is an important risk factor for cardiovascular and renal disease. The renin-angiotensin system is frequently implicated in the pathophysiology of hypertension, be it primary or secondary. The prevalence of primary aldosteronism increases with the severity of hypertension, from 2% in patients with grade 1 hypertension to 20% among resistant hypertensives. Mineralcorticoid hypertension includes a spectrum of disorders ranging from renin-producing pathologies (renin-secreting tumors, malignant hypertension, coarctation of aorta), aldosterone-producing pathologies (primary aldosteronism - Conns syndrome, familial hyperaldosteronism 1, 2, and 3), non-aldosterone mineralocorticoid producing pathologies (apparent mineralocorticoid excess syndrome, Liddle syndrome, deoxycorticosterone-secreting tumors, ectopic adrenocorticotropic hormones (ACTH) syndrome, congenitalvadrenal hyperplasia), and drugs with mineraocorticoid activity (locorice, carbenoxole therapy) to glucocorticoid receptor resistance syndromes. Clinical presentation includes hypertension with varying severity, hypokalemia, and alkalosis. Ratio of plasma aldosterone concentraion to plasma renin activity remains the best screening tool. Bilateral adrenal venous sampling is the best diagnostic test coupled with a CT scan. Treatment is either surgical (adrenelectomy) for unilateral adrenal disease versus medical therapy for idiopathic, ambiguous, or bilateral disease. Medical therapy focuses on blood pressure control and correction of hypokalemia using a combination of anti-hypertensives (calcium channel blockers, angiotensin converting enzyme inhibitors, or angiotensin receptor blockers) and potassium-raising therapies (mineralcorticoid receptor antagonist or potassium sparing diuretics). Direct aldosterone synthetase antagonists represent a promising future therapy.

Three novel CYP17A1 gene mutations (A82D, R125X, and C442R) found in combined 17α-hydroxylase/17,20-lyase deficiency

The aim of this study was to analyze the structure and functional consequences of 3 novel mutations (A82D, R125X, and C442R) of the CYP17A1 gene found in 2 patients with combined 17α-hydroxylase/17,20-lyase deficiency (17OHD). Two Chinese 46, XY female patients were diagnosed with 17OHD based on clinical findings and biochemical results. The CYP17A1 gene was analyzed by polymerase chain reaction direct sequencing. An in vitro expression system was performed in HEK293 cells to analyze the mutant P450c17 activity compared with the wild type. Analysis of the CYP17A1 gene sequences in patient 1 showed compound heterozygous mutations A82D (g.417 C > A) in exon 1 and Y329fs (g.4869 T > A, 4871del) in exon 6; DNA sequencing analysis in patient 2 revealed compound heterozygous mutations R125X (g.2045 C > T) in exon 2 and C442R (g.6457 T > C) in exon 8. The mutations A82D, R125X, and C442R have not been reported previously. The functional study demonstrated that the A82D, R125X, and C442R mutations almost completely eliminate enzymatic activity. These results, which indicate that Ala 82 and Cys 442 are crucial for both 17-hydroxylase and 17,20-lyase activities, help define the structure-function relationship of the CYP17A1 gene. The novel mutations A82D, R125X, and C442R further clarify the patients' clinical manifestations of combined 17OHD.

Distinctive profile of the 17-hydroxylase and 17,20-lyase activities revealed by urinary steroid metabolomes of patients with CYP17 deficiency

OBJECTIVES

(1) Characterize serum (S) and urinary (U) steroid metabolites in complete CYP17 deficiency (cCYP17D); (2) analyze the relative 17α-hydroxylase (17OH) and 17,20-lyase (17,20L) activities in vivo; and (3) comparedata from the two most prevalent mutations in Brazil.

SUBJECTS AND METHODS

20 genotyped cCYP17D patients from a previously reported cohort were homozygous for W406R or R362C; 11 controls were CYP17 wild types (WT). WT and cCYP17D patients had S and U samples drawn to measure: cortisol (F), corticosterone (B), deoxycorticosterone (DOC), 18OH-B, 18OH-DOC, and 17OHP; and tetrahydro (TH)-B, THA, THDOC, THF+5α-THF, TH-cortisone, androsterone, etiocholanolone, 5-pregnenediol, 17OH-pregnenolone and pregnanetriol.

RESULTS

Compared to WT, cCYP17D patients had marked elevations of B, DOC, 18OH-B and 18OH-DOC, whereas 17OHP, F and adrenal androgens (AA) were reduced; U steroids parallel S findings. Metabolite ratios revealed that both 17OH and 17,20L activities were impaired in cCYP17D. There were nodifferences between W406R andR362C mutations.

CONCLUSIONS

cCYP17D patients show parallel overproduction/overexcretion of 17-deoxysteroids, and marked reduction of F and AA. In addition to 17OH, 17,20-L activity was also impaired in cCYP17D. W406 and R362C mutations disclose similar Sand U patterns.

Combined 17α-hydroxylase/17,20-lyase deficiency due to p.R96W mutation in the CYP17 gene in a Brazilian patient

Congenital adrenal hyperplasia (CAH) resulting from 17α-hydroxylase/17,20-lyase deficiency is a rare autosomal recessive disease and the second most common form of CAH in Brazil. We describe the case of a Brazilian patient with CYP17 deficiency (17α-hydroxylase/17,20-lyase deficiency) caused by a homozygous p.R96W mutation on exon 1 of the CYP17 gene, an unusual genotype in Brazilian patients with this form of CAH. The patient, raised as a normal female, sought medical care for lack of pubertal signs and primary amenorrhea at the age of 16 years. At evaluation, the presence of a 46,XY karyotype, hypertension and hypokalemia were observed. We emphasize the recognition of CYP17 deficiency in the differential diagnosis of cases of hypergonadotrophic hypogonadism and hypertension in young patients who need specific treatment for both situations.

Pubertal delay, hypokalemia, and hypertension caused by a rare form of congenital adrenal hyperplasia

A 17-year-old female presented with diffuse muscle weakness secondary to severe hypokalemia, metabolic alkalosis, and hypertension. Additional findings included delayed puberty with primary amenorrhea. Laboratory evaluation led to a diagnosis of 17 alpha-hydroxylase/17,20-lyase (P450c17) deficiency, a form of congenital adrenal hyperplasia (CAH). Her symptoms and metabolic derangements improved with glucocorticoid replacement to suppress ACTH production and mineralocorticoid excess, although she continues to require antihypertensive therapy. Estrogen replacement was initiated due to sex hormone insufficiency. This rare disorder should be considered when evaluating patients with pubertal delay and hypertension, particularly if there is associated hypokalemia.

Pubertal presentation in seven patients with congenital adrenal hyperplasia due to P450 oxidoreductase deficiency

CONTEXT

P450 oxidoreductase (POR) is a crucial electron donor to all microsomal P450 cytochrome (CYP) enzymes including 17α-hydroxylase (CYP17A1), 21-hydroxylase (CYP21A2) and P450 aromatase. Mutant POR causes congenital adrenal hyperplasia with combined glucocorticoid and sex steroid deficiency. P450 oxidoreductase deficiency (ORD) commonly presents neonatally, with disordered sex development in both sexes, skeletal malformations, and glucocorticoid deficiency.

OBJECTIVE

The aim of the study was to describe the clinical and biochemical characteristics of ORD during puberty.

DESIGN

Clinical, biochemical, and genetic assessment of seven ORD patients (five females, two males) presenting during puberty was conducted.

RESULTS

Predominant findings in females were incomplete pubertal development (four of five) and large ovarian cysts (five of five) prone to spontaneous rupture, in some only resolving after combined treatment with estrogen/progestin, GnRH superagonists, and glucocorticoids. Pubertal development in the two boys was more mildly affected, with some spontaneous progression. Urinary steroid profiling revealed combined CYP17A1 and CYP21A2 deficiencies indicative of ORD in all patients; all but one failed to mount an appropriate cortisol response to ACTH stimulation indicative of adrenal insufficiency. Diagnosis of ORD was confirmed by direct sequencing, demonstrating disease-causing POR mutations.

CONCLUSION

Delayed and disordered puberty can be the first sign leading to a diagnosis of ORD. Appropriate testosterone production during puberty in affected boys but manifest primary hypogonadism in girls with ORD may indicate that testicular steroidogenesis is less dependent on POR than adrenal and ovarian steroidogenesis. Ovarian cysts in pubertal girls may be driven not only by high gonadotropins but possibly also by impaired CYP51A1-mediated production of meiosis-activating sterols due to mutant POR.

The molecular biology, biochemistry, and physiology of human steroidogenesis and its disorders

Steroidogenesis entails processes by which cholesterol is converted to biologically active steroid hormones. Whereas most endocrine texts discuss adrenal, ovarian, testicular, placental, and other steroidogenic processes in a gland-specific fashion, steroidogenesis is better understood as a single process that is repeated in each gland with cell-type-specific variations on a single theme. Thus, understanding steroidogenesis is rooted in an understanding of the biochemistry of the various steroidogenic enzymes and cofactors and the genes that encode them. The first and rate-limiting step in steroidogenesis is the conversion of cholesterol to pregnenolone by a single enzyme, P450scc (CYP11A1), but this enzymatically complex step is subject to multiple regulatory mechanisms, yielding finely tuned quantitative regulation. Qualitative regulation determining the type of steroid to be produced is mediated by many enzymes and cofactors. Steroidogenic enzymes fall into two groups: cytochrome P450 enzymes and hydroxysteroid dehydrogenases. A cytochrome P450 may be either type 1 (in mitochondria) or type 2 (in endoplasmic reticulum), and a hydroxysteroid dehydrogenase may belong to either the aldo-keto reductase or short-chain dehydrogenase/reductase families. The activities of these enzymes are modulated by posttranslational modifications and by cofactors, especially electron-donating redox partners. The elucidation of the precise roles of these various enzymes and cofactors has been greatly facilitated by identifying the genetic bases of rare disorders of steroidogenesis. Some enzymes not principally involved in steroidogenesis may also catalyze extraglandular steroidogenesis, modulating the phenotype expected to result from some mutations. Understanding steroidogenesis is of fundamental importance to understanding disorders of sexual differentiation, reproduction, fertility, hypertension, obesity, and physiological homeostasis.

Six new cases confirm the clinical molecular profile of complete combined 17α-hydroxylase/ 17,20-lyase deficiency in Brazil

In 2004, Costa-Santos and cols. reported 24 patients from 19 Brazilian families with 17α-hydroxylase deficiency and showed that p.W406R and p.R362C corresponded to 50% and 32% of CYP17A1 mutant alleles, respectively. The present report describes clinical and molecular data of six patients from three inbred Brazilian families with 17α-hydroxlyse deficiency. All patients had hypogonadism, amenorrhea and hypertension at diagnosis. Two sisters were found to be 46,XY with both gonads palpable in the inguinal region. All patients presented hypergonadotrophic hypogonadism, with high levels of ACTH (> 104 ng/mL), suppressed plasmatic renin activity, low levels of potassium (< 2.8 mEq/L) and elevated progesterone levels (> 4.4 ng/mL). Three of them, including two sisters, were homozygous for p.W406R mutation and the other three (two sisters and one cousin) were homozygous for p.R362C. The finding of p.W406R and p.R362C in the CYP17A1 gene here reported in additional families, confirms them as the most frequent mutations causing complete combined 17α-hydroxylase/17,20-lyase deficiency in Brazilian patients.

Defects of steroidogenesis

In the biosynthesis of steroid hormones the neutral lipid cholesterol, a normal constituent of lipid bilayers is transformed via a series of hydroxylation, oxidation, and reduction steps into a vast array of biologically active compounds: mineralocorticoids, glucocorticoids, and sex hormones. Glucocorticoids regulate many aspects of metabolism and immune function, whereas mineralocorticoids help maintain blood volume and control renal excretion of electrolytes. Sex hormones are essential for sex differentiation in male and support reproduction. They include androgens, estrogens, and progestins. A block in the pathway of steroid biosynthesis leads to the lack of hormones downstream and accumulation of the upstream compounds that can activate other members of the steroid receptor family. This review deals with the clinical consequences of these blocks.

17-alpha-hydroxylase deficiency: a case report with clinical and molecular analysis

BACKGROUND

17alpha-Hydroxylase deficiency (17OHD) is a rare disease of congenital adrenal hyperplasia. It is characterised by hypertension, hypokalaemia, primary amenorrhoea. Deficiency of P450c17 enzyme is caused by mutation of the CYP17 gene.

CASE

A 16-year-old female with genotypic 46, XY suffered from 17OHD. She presented with primary amenorrhoea, lack of secondary sexual characteristics, and hypertension. Laboratory tests showed hypokalaemia, low levels of androgens (testosterone and dehydroepiandrosterone), corticosteroid, and high levels of adrenocorticotropic hormone and progesterone. A P409R mutation was found in exon7 of CYP17 gene, revealing homozygosis and confirming diagnosis of 17OHD.

CONCLUSION

17OHD is a rare disease associated with primary amenorrhoea and hypertension. Identification of mutation in CYP17 gene can help to a better understanding of this enzyme deficiency.

46,XY DSD due to impaired androgen production

Disorders of androgen production can occur in all steps of testosterone biosynthesis and secretion carried out by the foetal Leydig cells as well as in the conversion of testosterone into dihydrotestosterone (DHT). The differentiation of Leydig cells from mesenchymal cells is the first walk for testosterone production. In 46,XY disorders of sex development (DSDs) due to Leydig cell hypoplasia, there is a failure in intrauterine and postnatal virilisation due to the paucity of interstitial Leydig cells to secrete testosterone. Enzymatic defects which impair the normal synthesis of testosterone from cholesterol and the conversion of testosterone to its active metabolite DHT are other causes of DSD due to impaired androgen production. Mutations in the genes that codify the enzymes acting in the steps from cholesterol to DHT have been identified in affected patients. Patients with 46,XY DSD secondary to defects in androgen production show a variable phenotype, strongly depending of the specific mutated gene. Often, these conditions are detected at birth due to the ambiguity of external genitalia but, in several patients, the extremely undervirilised genitalia postpone the diagnosis until late childhood or even adulthood. These patients should receive long-term care provided by multidisciplinary teams with experience in this clinical management.

Aromatase deficiency in men: a clinical perspective

Human aromatase deficiency is a very rare syndrome characterized by congenital estrogen deprivation that is caused by loss-of-function mutations in CYP19A1, which encodes aromatase. Here, we review the presentation, diagnosis and treatment of aromatase deficiency in men to provide useful advice for clinical management of the condition. At presentation, all men with aromatase deficiency have tall stature, delayed bone maturation, osteopenia or osteoporosis and eunuchoid skeletal proportions. Diagnosis of the condition is supported by the presence of unfused epiphyses and undetectable serum estradiol levels; the condition can be further substantiated by genetic sequencing of CYP19A1. Transdermal estradiol treatment at a daily dose of about 25 microg might be adequate for lifelong replacement therapy. BMD and levels of serum estradiol, luteinizing hormone and testosterone should be monitored carefully and considered powerful biochemical markers of adequate estrogen substitution in clinical practice. Early diagnosis is important to initiate estrogen therapy as soon after puberty as possible to avoid the skeletal complications that are associated with this condition.

Diagnosis of diseases of steroid hormone production, metabolism and action

Biochemical tests have been the basis for investigations of disorders affecting steroid hormones. In recent years it has been possible however to study the genes that determine functional enzymes, cofactors, receptors, transcription factors and signaling systems that are involved in the process. Analyses of mutations are available as a diagnostic service for only a few of these genes although research laboratories may be able to provide a service. Both biochemical and genetic research have brought to light new disorders. Some genes for transcription factors involved in the development of the endocrine organs have also been identified and patients with defects in these processes have been found. This paper will review general aspects of adrenal disorders with emphasis on clinical and laboratory findings. As with all endocrine investigations there are few single measurements that provide a definitive answer to a diagnosis. Timing of samples in relation to age, gender and time of day needs to be considered.

Steroid 17alpha-hydroxylase deficiency: functional characterization of four mutations (A174E, V178D, R440C, L465P) in the CYP17A1 gene

CONTEXT

Steroid 17alpha-hydroxylase (CYP17A1, alias P450c17) deficiency (17OHD) is a rare form of congenital adrenal hyperplasia. The CYP17A1 enzyme catalyzes two distinct reactions, 17alpha-hydroxylase and 17,20-lyase activities.

OBJECTIVE

The aim of the study was to analyze the structural and functional consequences of three novel (A174E, V178D, and L465P) and one previously reported (R440C) CYP17A1 mutation found in three patients clinically and biochemically presenting with 17OHD.

PATIENTS AND METHODS

Two patients suffering from 46,XY disordered sex development presented at ages 5.5 and 8.8 yr, respectively, with tall stature and hypertension. Mutation analysis revealed compound heterozygous CYP17A1 mutations (A174E/K388X; V178D/R440C). The third patient (46,XX) presented with primary amenorrhea and hypertension at age 15 yr. She was homozygous for the novel L465P mutation. Functional studies employing a yeast microsomal expression system compared wild-type and mutant CYP17A1 both with regard to 17alpha-hydroxylase and 17,20-lyase activity. Mutants were examined in a computational three-dimensional model of the CYP17A1 protein.

RESULTS

The activity assays showed that all three mutants retain only 0-7% of both 17alpha-hydroxylase and 17,20-lyase activity relative to CYP17A1 wild-type activity, corresponding to the in vivo situation. Enzyme kinetic studies proved the impairment of both reactions, respectively. Computer-based three-dimensional model analysis of CYP17A1 using CYP2B4 as template showed that three of the mutations had no direct effect on the active center, whereas one affects the heme coordination.

CONCLUSION

The functional studies revealed that the described missense mutations result in severe 17OHD. Our data are important to predict the phenotypic expressions and provide important information for patient management and genetic counseling.

46,XY disorders of sex development (DSD)

The term disorders of sex development (DSD) includes congenital conditions in which development of chromosomal, gonadal or anatomical sex is atypical. Mutations in genes present in X, Y or autosomal chromosomes can cause abnormalities of testis determination or disorders of sex differentiation leading to 46,XY DSD. Detailed clinical phenotypes allow the identification of new factors that can alter the expression or function of mutated proteins helping to understand new undisclosed biochemical pathways. In this review we present an update on 46,XY DSD aetiology, diagnosis and treatment based on extensive review of the literature and our three decades of experience with these patients.

Neurobiological and neuropsychiatric effects of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS)

DHEA and DHEAS are steroids synthesized in human adrenals, but their function is unclear. In addition to adrenal synthesis, evidence also indicates that DHEA and DHEAS are synthesized in the brain, further suggesting a role of these hormones in brain function and development. Despite intensifying research into the biology of DHEA and DHEAS, many questions concerning their mechanisms of action and their potential involvement in neuropsychiatric illnesses remain unanswered. We review and distill the preclinical and clinical data on DHEA and DHEAS, focusing on (i) biological actions and putative mechanisms of action, (ii) differences in endogenous circulating concentrations in normal subjects and patients with neuropsychiatric diseases, and (iii) the therapeutic potential of DHEA in treating these conditions. Biological actions of DHEA and DHEAS include neuroprotection, neurite growth, and antagonistic effects on oxidants and glucocorticoids. Accumulating data suggest abnormal DHEA and/or DHEAS concentrations in several neuropsychiatric conditions. The evidence that DHEA and DHEAS may be fruitful targets for pharmacotherapy in some conditions is reviewed.

Disorders of sexual differentiation in the adolescent

Disorders of sexual differentiation (DSDs) presenting during adolescence are discussed, and molecular explanations are given for some. DSD conditions are often discovered during early adolescence, an age well known to predispose to high risk for adjustment problems. Presentation may be with lack of or minimal pubertal development, lack of menarche, vaginal, uterine, or breast agenesis and inappropriate sexual development such as virilization in females or feminization (gynecomastia) in males. Most such disorders require life-long therapy, with many of the medical, surgical and psychological aspects of management being accentuated during adolescence. Regardless of the age at presentation, all require skillful management to promote normal health and well-being. This care ideally involves specialists in endocrinology and medical therapy, psychology and, if required, surgery. A brief discussion of the needs of the adolescent with DSDs is presented.