Screening for mutations of 21-hydroxylase gene in Hungarian patients with congenital adrenal hyperplasia

Bone mineral density and trabecular bone score in patients with 21-hydroxylase deficiency after glucocorticoid treatment

OBJECTIVE

Patients with 21-hydroxylase deficiency (21-OHD) are at risk of reduced bone mineral density (BMD) and fracture due to long-term glucocorticoid treatment. Trabecular bone score (TBS) is complementary to conventional BMD as a marker for bone quality in patients with glucocorticoid-induced osteoporosis. The purpose of this study is to evaluate the BMD and TBS in a cohort of patients with 21-OHD and analyse factors related to TBS.

DESIGN

An observational study.

PATIENTS

A total of 46 21-OHD adult patients treated with glucocorticoid for over 10 years who visited Peking Union Medical College Hospital between 2015 and 2019 were recruited. Eight male patients included in this study were all under 50 years old, and 38 female patients were all premenopausal.

MEASUREMENTS

Diagnosis was confirmed by multiplex ligation-dependent probe amplification combined with sequencing. Data were collected on physical characteristics, serum hormones and glucocorticoid treatment. Skeletal quality was evaluated by BMD and TBS, and factors related to TBS were analysed.

RESULTS

Among the 46 patients, 2 (4.3%) had low BMD (Z-score ≤ -2), while 11 (23.9%) patients had low TBS (degraded or partially degraded microarchitecture). The proportion of bone abnormality evaluated by TBS was higher than that by BMD (p < .001). Patients with lower TBS had significantly higher daily hydrocortisone dosage (p = .009 for males; p = .019 for females). TBS value was negatively correlated with daily hydrocortisone dosage (r = -.317, p = .026), and positively correlated with BMI in female patients (r = .345, p = .034). And there was a negative correlation between TBS value and the current age in male patients (r = -.741, p = .036). The distribution of genotypes (p = 1.000 for male; p = .567 for female) or phenotypes (p = .486 for male; p = .075 for female) had no statistical difference in patients with normal or abnormal TBS.

CONCLUSIONS

Approximately 24% of patients with 21-OHD had abnormal microarchitecture of their bone in our study, and TBS score was negatively correlated with daily glucocorticoid dosage in patients. TBS may be used alongside conventional BMD as a complementary marker for bone evaluation in 21-OHD patients.

Polycystic Ovary Syndrome and NC-CAH: Distinct Characteristics and Common Findings. A Systematic Review

Background: Twenty-one-hydroxylase-deficient non-classic adrenal hyperplasia (NC-CAH) is a very common autosomal recessive syndrome with prevalence between 1:1,000 and 1:2,000 individuals and the frequency varies according to ethnicity. On the other hand, polycystic ovary syndrome has a familial basis and it is inherited under a complex hereditary trait. This syndrome affects 6 to 10% of women in reproductive age and it is the most common endocrine disorder in young women. Our aim was to investigate, through a systematic review, the distinct characteristics and common findings of these syndromes. Methods: The search period covered January 1970 to November 2018, using the scientific databases PubMed. Inclusion criteria were adult women patients with PCOS or NC-CAH. Search terms were "polycystic ovary syndrome," "PCOS," "non-classical adrenal hyperplasia," "NC-CAH," "21-hydroxylase deficiency." From an initial 16,255 titles, the evaluations led to the final inclusion of 97 papers. Results: The clinical features of NC-CAH are hirsutism and ovulatory and menstrual dysfunction therefore; differentiation between these two syndromes is difficult based on clinical grounds only. Additionally, NC-CAH and PCOS are both associated with obesity, insulin resistance, and dyslipidaemia. Reproductive abnormalities are also common between these hyperandrogenemic disorders since in patients with NC-CAH polycystic ovarian morphology and subfertility are present as they are in women with PCOS. The diagnosis of PCOS, is confirmed once other disorders that mimic PCOS have been excluded e.g., conditions that are related to oligoovulation or anovulation and/or hyperandrogenism, such as hyperprolactinaemia, thyroid disorders, non-classic congenital adrenal hyperplasia, and androgen-producing neoplasms. Conclusions: The screening tool to distinguish non-classic adrenal hyperplasia from PCOS is the measurement of 17-hydroxyprogesterone levels. The basal levels of 17-hydroxyprogesterone may overlap, but ACTH stimulation testing can distinguish the two entities. In this review these two common endocrine disorders are discussed in an effort to unveil their commonalities and to illuminate their shadowed distinctive characteristics.

Pitfalls in molecular diagnosis of 21-hydroxylase deficiency in congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) is a putative error of metabolism with autosomal recessive heredity pattern. The main manifestations of classic form of CAH are salt-wasting, dehydration and simple virilization in both sexes and ambiguous genitalia in female gender. 21-hyroxylase (CYP21A2) impairment with prevalence value of 1 in 10,000-15,000 live births is the most common etiology of CAH. Because of consanguineous marriages, the frequency of the CAH in Iran is very high. A wide range of mutations diversity exists in CYP21A2 gene and a large number of these mutations derived from a highly homologous pseudogene, CYP21A1P, through gene conversion. In addition, new mutations such as small and large deletion and point mutations can also result in enzyme deficiency. Various methods for mutation detection were performed. The main obstacle in molecular diagnosis of CAH is amplification of pseudogene during polymerase chain reaction of CYP21A2. All attempts focus on discrimination of pseudogene from gene; that is why, there is the majority of mutations on pseudogene, and if we have contamination with the pseudogene, the result will be unreliable. Here, we discuss this methods and advantage and disadvantage of those.

Clinical profile and inheritance pattern of CYP21A2 gene mutations in patients with classical congenital adrenal hyperplasia from 10 families

CONTEXT

Congenital adrenal hyperplasia (CAH) is an autosomal recessive metabolic disorder caused by mutations in the CYP21A2 gene. Genetic diagnosis of 21-OH deficiency causing CAH is more complicated than any other monogenic disorder due to high variability of the locus. The disease has a wide spectrum of clinical variants making it difficult to establish a genotyp-phenotype correlation. Therefore, family studies are necessary to ascertain parental genotype and segregation of the mutant allele among the offspring.

AIM

The present study aimed to identify CYP21A2 gene mutations and analyze the segregation pattern in CAH trios (patients and their parents).

MATERIALS AND METHODS

A total of ten families having at least one CAH child were recruited.

RESULTS

Out of 31 children from ten families, 15 were affected with CAH and 13 of/them (12 females and 1 male) were available for genetic testing. One family had all the children affected with CAH. Compound heterozygous mutations were identified in seven patients (53.8%) whereas p.P30L, In2 and Δ8 bp mutations were present in homozygous state in three (23.1%), two (15.3 %) and one (7.6%) patient respectively.

CONCLUSIONS

In majority of the families, mutant alleles observed in the patients were inherited from the parents whereas three families showed sporadic mutations without any paternal or maternal origin. This indicated their novel occurrence due to misalignment of the parental genes and/or large deletion of the gene. Female preponderance was noted in the CAH families and also among the patients raising the possibility of survival advantage among females.

Profiles of 21-Carbon Steroids in 21-hydroxylase Deficiency

CONTEXT

Marked elevations of 17-hydroxyprogesterone (17OHP) are characteristic of classic 21-hydroxylase deficiency (21OHD). Testing of 17OHP provides the basis for 21OHD diagnosis, although it suffers from several pitfalls. False-positive or false-negative results and poor discrimination of nonclassic 21OHD from carriers limit the utility of serum 17OHP and necessitate dynamic testing after cosyntropin stimulation when values are indeterminate.

OBJECTIVE

The objective was to provide a detailed characterization of 21-carbon (C21) steroids in classic 21OHD, which might identify other candidate steroids that could be employed for the diagnosis of 21OHD.

SETTING AND PARTICIPANTS

Patients (11 women, 10 men) with classic 21OHD and 21 sex- and age-matched controls seen in a tertiary referral center were studied.

METHODS

C21 steroids in the peripheral sera from all subjects, as well as in media from cultured testicular adrenal rest tumor (TART) cells and normal adrenal (NA) cells, were analyzed using liquid chromatography/tandem mass spectrometry (10 steroids). Additionally, the dynamics of C21 steroid metabolism in TART and NA cells were assessed with radiotracer studies.

RESULTS

Five C21 steroids were significantly higher in 21OHD patients: 17OHP (67-fold; P < .01), 21-deoxycortisol (21dF; 35-fold; P < .01), 16α-hydroxyprogesterone (16OHP; 28-fold; P < .01), progesterone (2-fold; P < .01), and 11β-hydroxyprogesterone (11OHP; not detected in controls; P < .01). The same steroids were the highest in media from TART cells relative to the NA cells: 11OHP, 58- to 65-fold; 21dF, 30- to 41-fold; 17OHP, 9-fold; progesterone, 9- to 12-fold; and 16OHP, 7-fold.

CONCLUSION

Measurement of 16OHP and 11OHP along with 17OHP and 21dF by liquid chromatography/tandem mass spectrometry might comprise a biomarker panel to accurately diagnose all forms of 21OHD.

CYP21A2 gene mutations in congenital adrenal hyperplasia: genotype-phenotype correlation in Turkish children

BACKGROUND

Congenital adrenal hyperplasia (CAH) due 21-hydroxylase deficiency (21-OHD) is a common autosomal recessive disorder. It is caused by defects in the CYP21A2 gene.

OBJECTIVE

Our aim was to determine the frequency of common gene mutations and to evaluate genotype-phenotype correlations in Turkish 21-OHD patients.

METHODS

Molecular analysis of the CYP21A2 gene was performed for the detection of the eight most common point mutations [p.P30L, IVS2-13C>G (IVS-2), p.I172N, exon 6 mutation cluster (p.I236N, p.V237E, p.M239K), p.V281L, p.Q318X, p.R356W, 8-bp-deletion], of large deletion and conversion by southern blotting, allele specific semi-quantitative PCR/enzyme restriction method and sequencing, in 56 patients with 21-OHD, from 52 families.

RESULTS

Disease-causing mutations were identified in 77 out of 91 alleles (84.6%) of the patients. Mutations were found in 34 of 43 alleles (79.1%) in salt wasting (SW; n=26), 32 of 36 alleles (88.8%) in simple virilizing (SV; n=24) and 11 of 12 alleles (91.6%) in non-classical (NC; n=6) form of CAH. The most frequent mutations were IVS-2 (22.0%), large conversion (14.3%), p.I172N (9.9%) p.R356W (8.8%), and large deletion (6.6%). In the SW form, the most frequent genotypes were homozygous for IVS-2 (11.5%) and homozygous for large conversion of the gene (11.5%). In the SV form, the most frequent genotype was homozygous for IVS-2 (20%), followed by compound heterozygous for p.I172N/8-bp del (10%). Homozygous for p.V281L (16.7%) was most common in NC. In most cases there was good correlation between genotype and phenotype. In the SW and NC forms, genotypes of all the patients correlated with their phenotypes.

CONCLUSIONS

This is the first comprehensive study on the molecular basis of CAH patients in the Turkish population. Based on these results, we propose a modified screening strategy to facilitate molecular testing of CAH patients in our population.