A sequence variation in 3'UTR of CYP21A2 gene correlates with a mild form of congenital adrenal hyperplasia

CYP21A2 mutations in pediatric patients with congenital adrenal hyperplasia in Costa Rica

Steroid 21-hydroxylase deficiency accounts for 95% of congenital adrenal hyperplasia (CAH) cases. Newborn screening has allowed for early detection of the disease, and currently, molecular analysis can identify the genotypes of these patients. Phenotype-genotype correlation has been well described in previous studies. In Costa Rica, there is no data about the genetic background of these patients, nor their phenotypic correlation.

Design

Observational, retrospective, descriptive study based on the review of patient records who had a diagnosis of CAH and were performed molecular analysis using gene sequencing or MLPA during the period from 2006 to 2018 (N = 58).

Objective

To describe the clinical and genetic characteristics of CAH patients due to 21-hydroxylase deficiency at the National Children's Hospital “Dr. Carlos Sáenz Herrera”, Caja Costarricense de Seguro Social (CCSS) in Costa Rica.

Results

53% (31/58) of the patients were male and 80% (37/46) were born full term; 72% (42/58) had salt wasting phenotype, 9% (5/58) simple virilizing phenotype and 19% (11/58) non-classic phenotype. The most frequent variants were c.292+5G>A in 26% (15/58) of patients and Del/Del in 21% (12/58) of them.

Conclusions

The most frequent mutation in our study population was the c.292+5G>A, which was found in 15/58 patients. This rare variant has only been reported in three other studies so far but as an infrequent mutation in CAH patients. The genetic characteristics of Costa Rican patients differ from what has been documented worldwide and could respond to a founder effect.

Genotype Is Associated to the Degree of Virilization in Patients With Classic Congenital Adrenal Hyperplasia

Background: Molecular defects of CYP21A2 consistently decrease 21-hydroxylase activity and result in a variable expression of disease severity in patients with congenital adrenal hyperplasia (CAH). Aim: The genotype and biochemical findings were examined in an attempt to reveal any association to the degree of virilization in classic CAH patients. Methods: The study included 18 CAH patients with complete characterization of CYP21A2 mutations and were sorted based on the severity of the inherited mutations and the expected percentage of 21-hydroxylase enzyme activity. Results: Eleven out of the 18 patients manifested the SW form with the remaining seven exhibiting the SV form. The most frequent genetic defect in the classic salt-wasting (SW) and simple virilising (SV) forms was the IVS2-13A/C>G (36.1%) mutation, followed by delEX1-3 (19.4%) and p.Ile172Asn (19.4%). Four patients, who shared a combination of two mutations belonging to the most severe type, manifested only the SW form. Four out of five patients who shared homozygosity in the IVS2-13A/C>G mutation, demonstrated the SW form and only one demonstrated the SV form. All four patients who shared the p.Ile172Asn mutation, either in the homozygous or compound heterozygous state, manifested the SV form. Interestingly, a female neonate with SW, bearing the IVS2-13A/C>G/Large del, exhibited complete male virilisation (Prader 5). The remaining four affected female new-borns also exhibited the SW form, with two of them virilised as Prader 3 and the other two as Prader 4. Virilisation with clitoromegaly was also observed in one female, who presented premature adrenarche and carried the least severe p.Pro30Leu mutation. Conclusion: The frequency of the underlying mutations in our patients, with the classic form of CAH, varies but were quite similar to the ones reported in the Mediterranean region. Therefore, the identification of severe CYP21A2 defects in Cypriot patients and their comparison with the incidence and severity in different populations, will create a valuable diagnostic tool for genetic counseling in the classic form of CAH.

Variations in the 3'UTR of the CYP21A2 Gene in Heterozygous Females with Hyperandrogenaemia

Heterozygosity for CYP21A2 mutations in females is possibly related to increased risk of developing clinical hyperandrogenism. The present study was designed to seek evidence on the phenotype-genotype correlation in female children, adolescents, and women with CYP21A2 mutations and variants in the 3'UTR region of the gene. Sixty-six patients out of the 169 were identified as carriers of CYP21A2 mutations. Higher values of stimulated 17 hydroxyprogesterone (17-OHP) levels were found in the carriers of the p.Val281Leu mutation compared to the carriers of other mutations (mean: 24.7 nmol/l versus 15.6 nmol/l). The haplotype of the ∗52C>T, ∗440C>T, and ∗443T>C in the 3'UTR was identical in all heterozygous patients with p.Val281Leu and the haplotype of the ∗12C>T and ∗52C>T was identical in all heterozygous patients with the p.Gln318∗. In conclusion, hyperandrogenaemic females are likely to bear heterozygous CYP21A2 mutations. Carriers of the mild p.Val281Leu mutation are at higher risk of developing hyperandrogenism than the carriers of more severe mutations. The identification of variants in the 3'UTR of CYP21A2 in combination with the heterozygous mutation may be associated with the mild form of nonclassic congenital adrenal hyperplasia and reveal the importance of analyzing the CYP21A2 untranslated regions for the appropriate management of this category of patients.

Mutation detection of CYP21A2 gene in nonclassical congenital adrenal hyperplasia patients with premature pubarche

Background:

Congenital adrenal hyperplasia (CAH) due to mutations in the gene encoding 21-hydroxilase is one of common disease with an autosomal recessive form. In this study, our aim is to detect the prevalence of eight common mutations in nonclassical congenital adrenal hyperplasia (NCAH).

Materials and Methods:

A total of 30 patients with clinical and laboratory evidence of NCAH was selected. Gene-specific polymerase chain reaction (PCR) without contamination of pseudogene was carried out, and PCR product of this step was used to amplification-refractory mutation system PCR on eight common mutations in CYP21A2 gene.

Results:

Two heterozygote patients for I2G mutation and six heterozygote patients for Q318X mutation is reported in our study. These mutations associated with the classic form of CAH, and heterozygotes presented with NC symptom, including premature pubarche and hirsutism.

Conclusion:

There are some data about the association of the mutation with the clinical form of CAH including classic (salt-wasting and simple virilizing) and NC form. I2G and Q318X mutations were reported in classic form in homozygote state, but the heterozygote form associated with NC form. CAH diagnosis with NC symptom and with measurement of 17-hydroxyprogestrone as NCAH is not a trusted assessment and require to molecular analysis for accurate diagnosis.

High frequency of splice site mutation in 21-hydroxylase deficiency children

PURPOSE

Steroid 21-hydroxylase deficiency (21-OHD) is the common type of congenital adrenal hyperplasia (CAH) caused by defects in the CYP21A2 gene, as an autosomal recessive disease, genetic analysis has a prominent role in its diagnosis. Our objectives were to determine the prevalence of common mutations in a group of Egyptian patients with 21-OHD and their families using rapid methods, and also to detect the rate of deletion, duplication and conversions in CYP21A2 gene.

METHODS

Rapid detection methods were used: allele-specific PCR for c.293-13A>G (g.659A>G), c.518T>A (p.I172N) variants and c.332_339del (8-bp deletion in exon 3), and real-time, quantitative PCR assay was used to detect deletion in the CYP21A2 gene. 29 Egyptian patients, 38 family members, and 20 healthy controls were all included in the study.

RESULTS

The frequency of c.293-13A>G splice mutation was reported in 96.6 % cases, G allele had 2.5-folds higher risk to develop CAH than other alleles. The c.518T>A mutation was reported in 69 % cases, children carrying the mutant allele were 2.1 times more risk. The most frequent combined mutations detected were c.293-13A/C>G/c.518T>A in 58.6 % cases.

CONCLUSION

The genetic analysis of the splice site mutation c.293-13A>G and c.518T>A variant can be used as good biomarkers for early detection of cases and carriers in 21-OHD CAH Egyptian children, since the methods used have rapid turnaround time.

Phenotypic variability of hyperandrogenemia in females heterozygous for CYP21A2 mutations

OBJECTIVES

The objective was to seek evidence on the prevalence and consequences of heterozygous CYP21A2 mutations in girls, adolescent, and adult females with clinical manifestation of androgen excess.

PATIENTS AND METHODS

The study included 64 girls diagnosed with premature adrenarche (PA) in childhood and 141 females with clinical hyperandrogenemia manifested in adolescence or adulthood. Direct DNA sequencing and multiplex ligation-dependent probe amplification analysis were used to identify mutations in the CYP21A2 gene.

RESULTS

(1) Thirty-four patients were diagnosed with nonclassical-congenital adrenal hyperplasia (NC-CAH) based on the 17-hydroxyprogesterone (17-OHP) levels and the presence of two mutations in CYP21A2 and therefore were excluded from the study, 66 were found to be heterozygotes and finally 105 had no identifiable mutations. The most frequent mutations among the carriers were the mild p.Val281 Leu and p.Qln318stop. Higher levels of mean stimulated 17-OHP were found in the carriers of the p.Val281 Leu. (2) A notable increased allelic frequency for the known p.Asn493 Ser polymorphism was observed in the pool of females with hyperandrogenemia in whom no mutation was identified. (3) In girls, who presented early with PA, 26.6% were diagnosed with NC-CAH and carried two mutations, 28.7% were identified as heterozygotes 43.7% had no identifiable genetic defect in the translated region of the CYP21A2 gene. On the contrary, in the group of 141 females with late onset hyperandrogenemia, the presence of 2 mutations was detected in 12%, 1 mutation in 33.4% and no mutation in 54.6%.

CONCLUSIONS

The carrier status for 21-OHD, may be an important factor in the variable phenotype of hyperandrogenism and may be a contributing factor for the early manifestation of the disease.

Impaired pre-mRNA processing and altered architecture of 3' untranslated regions contribute to the development of human disorders

The biological fate of each mRNA and consequently, the protein to be synthesised, is highly dependent on the nature of the 3' untranslated region. Despite its non-coding character, the 3' UTR may affect the final mRNA stability, the localisation, the export from the nucleus and the translation efficiency. The conserved regulatory sequences within 3' UTRs and the specific elements binding to them enable gene expression control at the posttranscriptional level and all these processes reflect the actual state of the cell including proliferation, differentiation, cellular stress or tumourigenesis. Through this article, we briefly outline how the alterations in the establishment and final architecture of 3' UTRs may contribute to the development of various disorders in humans.

Genotype-phenotype correlation in 1,507 families with congenital adrenal hyperplasia owing to 21-hydroxylase deficiency

Over the last two decades, we have extensively studied the genetics of congenital adrenal hyperplasia caused by 21-hydroxylase deficiency (CAH) and have performed 8,290 DNA analyses of the CYP21A2 gene on members of 4,857 families at risk for CAH--the largest cohort of CAH patients reported to date. Of the families studied, 1,507 had at least one member affected with one of three known forms of CAH, namely salt wasting, simple virilizing, or nonclassical CAH. Here, we report the genotype and phenotype of each affected patient, as well as the ethnic group and country of origin for each patient. We showed that 21 of 45 genotypes yielded a phenotypic correlation in our patient cohort. In particular, contrary to what is generally reported in the literature, we found that certain mutations, for example, the P30L, I2G, and I172N mutations, yielded different CAH phenotypes. In salt wasting and nonclassical CAH, a phenotype can be attributed to a genotype; however, in simple virilizing CAH, we observe wide phenotypic variability, particularly with the exon 4 I172N mutation. Finally, there was a high frequency of homozygous I2G and V281L mutations in Middle Eastern and Ashkenazi Jewish populations, respectively. By identifying the predominant phenotype for a given genotype, these findings should assist physicians in prenatal diagnosis and genetic counseling of parents who are at risk for having a child with CAH.