High Variability of CYP21 Gene Rearrangements in Spanish Patients with Classic Form of Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is one of the most common endocrine diseases, yet genetic diagnosis is among the most complicated of all monogenic disorders. It has an overall incidence of 1:10000-1:20000, it is inherited in autosomal recessive pattern and caused by mutations affecting CYP21A2 gene. Based on the phenotypic expression, this disease is categorized into severe, classical form revealed at birth and mild, non-classical form. Although diagnosis could be established based on biochemical tests and distinctive clinical features, molecular genetic testing is crucial for diagnosis confirmation, detection of carriers and asymptomatic patients, disease prognosis, as well as for providing proper genetic counselling and prenatal diagnosis. Based on CYP21A2 mutational spectrum and frequencies in Serbia, in this paper we propose an optimal molecular genetic diagnostic algorithm for CAH and discuss genetic mechanisms underlying the disease. The complete diagnostic procedure combines multiplex minisequencing technique (SNaPshot PCR) as a method for rapid detection of common point mutations, direct sequencing of whole CYP21A2 gene and PCR with sequence specific primers (PCR-SSP) for large gene rearrangements detection (CYP21A1P/CYP21A2 chimeras). While SNaPshot PCR assay analyses ten common mutations (c.290-13A/C>G, p.P30L, p.R356W, p.G110fs, p.V281L, p.Q318X, p.L307fs, p.I172N, Cluster p.[I236N;V237E;M239K] and p.P453S) which account for over 80% of all CYP21A2 mutations in Serbian population, direct sequencing of CYP21A2 gene is needed to identify potential rare or novel mutations present in Serbian population with frequency of 1.8%. Additionally, large gene rearrangements which are present with frequency of 16.7% make PCR-SSP analysis an unavoidable part of molecular characterization of CAH in Serbia. Described molecular genetic strategy is intended to facilitate correct diagnosis assessment in CAH affected individuals and their families in Serbia but it will also contribute to molecular genetic testing of CAH patients across Europe.

Download Full-text

Adverse Effects of Ramadan Fasting in a Girl with Salt-Losing Congenital Adrenal Hyperplasia

Case Reports in Endocrinology ◽

10.1155/2020/6688927 ◽

2020 ◽

Vol 2020 ◽

pp. 1-3

Author(s):

Valeria Calcaterra ◽

Francesco Bassanese ◽

Andrea Martina Clemente ◽

Rossella Amariti ◽

Corrado Regalbuto ◽

...

Keyword(s):

Congenital Adrenal Hyperplasia ◽

Adrenal Insufficiency ◽

Treatment Plan ◽

Management Plan ◽

Hormonal Control ◽

Adrenal Crisis ◽

Adrenal Hyperplasia ◽

Ramadan Fasting ◽

Salt Wasting ◽

Classic Form

Objective. Congenital adrenal hyperplasia (CAH) is the most common cause of adrenal insufficiency in pediatrics. Chronic glucocorticoid replacement is the mainstay of treatment in the classic forms of CAH, and mineralocorticoid replacement therapy is mandatory in the salt-wasting form. Fasting is a mild stressor, which can expose to dehydration, hypotension, hypoglycemia, and acute adrenal crisis in patients with adrenal insufficiency. Case. We report the case of an adolescent affected by the classic form with salt-losing CAH, who observed Ramadan for 30 days, without individualized therapeutic management plan. After Ramadan, a dramatic increase of ACTH level (1081 pg/ml, n.v. 6–57), reduced cortisolemia, tendency to hypotension, and weight loss were recorded. She experienced insomnia, intense thirst, asthenia, and headache. The symptoms disappeared restarting the previous therapy schedule and increasing the total hydrocortisone daily dose with progressive restoring of hormonal control. Conclusion. Our case confirms that patients with CAH are vulnerable, especially during fasting in Ramadan, with a higher risk of acute adrenal crisis. CAH patients should reform and individualize their treatment plan and be submitted to careful monitoring.

Download Full-text

Identification of three mutatons in the cyp21 gene in Vietnamese patients having signs of congenital adrenal hyperplasia

TAP CHI SINH HOC ◽

10.15625/0866-7160/v35n2.3112 ◽

2013 ◽

Vol 35 (2) ◽

Author(s):

Le Bac Viet ◽

Nguyen Thi Phuong Mai ◽

Nguyen Huy Hoang

Keyword(s):

Congenital Adrenal Hyperplasia ◽

Adrenal Hyperplasia ◽

Cyp21 Gene

Download Full-text

Mutation of IVS2 –12A/C>G in Combination with 707–714delGAGACTAC in the CYP21 Gene Is Caused by Deletion of the C4-CYP21 Repeat Module with Steroid 21-Hydroxylase Deficiency

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jc.2003-030047 ◽

2003 ◽

Vol 88 (6) ◽

pp. 2726-2729 ◽

Cited By ~ 12

Author(s):

Hsien-Hsiung Lee ◽

Shwu-Fen Chang ◽

Fuu-Jen Tsai ◽

Li-Ping Tsai ◽

Ching-Yu Lin

Keyword(s):

Congenital Adrenal Hyperplasia ◽

Donor Site ◽

Adrenal Hyperplasia ◽

Hydroxylase Deficiency ◽

Aberrant Splicing ◽

Cyp21 Gene ◽

Pcr Product ◽

Intergenic Recombination ◽

21 Hydroxylase Deficiency

More than 90% of the cases of congenital adrenal hyperplasia are caused by mutations of the CYP21 gene. Approximately 75% of the defective CYP21 genes are generated through intergenic recombination, termed apparent gene conversion, from the neighboring CYP21P pseudogene. Among them, mutation of the aberrant splicing donor site of IVS2 –12A/C>G at nucleotide (nt) 655 is believed to be a result derived from this mechanism and is the most prevalent case among all ethnic groups. However, mutation of 707–714delGAGACTAC rarely exists alone, although this locus is a distance of 53 nt away from IVS2 –12A/C>G. From the molecular characterization of the mutation of IVS2 –12A/C>G combined with 707–714delGAGACTAC in patients with congenital adrenal hyperplasia, we found that it appeared to be in a 3.2-rather than a 3.7-kb fragment generated by Taq I digestion in a PCR product of the CYP21 gene. Interestingly, the 5′ end region of such a CYP21 haplotype had CYP21P-specific sequences. Our results indicate that the coexistence of these two mutations is caused by deletion of the CYP21P, XA, RP2, and C4B genes and intergenic recombination in the C4-CYP21 repeat module. Surprisingly, this kind of the haplotype of the mutated CYP21 gene has not been reported as a gene deletion.

Download Full-text

Study of a Kindred with Classic Congenital Adrenal Hyperplasia: Diagnostic Challenge due to Phenotypic Variance1

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jcem.83.6.4887 ◽

1998 ◽

Vol 83 (6) ◽

pp. 1940-1945

Author(s):

Daisy Chin ◽

Phyllis W. Speiser ◽

Julianne Imperato-McGinley ◽

Naznin Dixit ◽

Naveen Uli ◽

...

Keyword(s):

Congenital Adrenal Hyperplasia ◽

Newborn Screening ◽

Point Mutation ◽

Phenotypic Expression ◽

Variable Degree ◽

Adrenal Hyperplasia ◽

Cyp21 Gene ◽

Classic Congenital Adrenal Hyperplasia ◽

Genital Ambiguity ◽

21 Hydroxylase Deficiency

We sought to determine the concordance of the phenotype and genotype in a kindred with classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency. The variation in phenotypic expression within this family underscores the difficulty of establishing the diagnosis in the absence of newborn screening, even with a heightened index of suspicion. Steroidogenic profiles were obtained for the three affected siblings. The available clinical history of the two affected aunts was retrieved. Genotyping was performed on several members of the kindred. Detailed sequencing of the entire CYP21 gene of two clinically dissimilar subjects in this family was undertaken to explore the possibility of other mutations or polymorphisms. PCR with ligase detection reaction analysis of CYP21 revealed that the affected family members III-2, III-3, III-4, II-3, and II-4, all were compound heterozygotes carrying the intron 2 point mutation known to interfere with splicing (nucleotide 656 A to G) and the exon 4 point mutation causing a nonconservative substitution of asparagine for isoleucine at codon 172 (I172N). Detailed sequencing of the gene was performed for the two most phenotypically dissimilar subjects. A single silent polymorphism was found in the third nucleotide for codon 248 in patient II-4, but not in patient III-4, and no additional mutations were found. Classic congenital adrenal hyperplasia remains a difficult diagnosis to make in the absence of newborn screening because of the variability of phenotypic expression. Likewise, the variable degree of genital ambiguity in affected females in this family serves to question universal advocacy of prenatal steroid treatment in pregnancies at risk for congenital adrenal hyperplasia. Extensive molecular exploration did not provide an explanation of the phenotypic heterogeneity and supports the possibility of influences other than the CYP21 gene for the observed divergence.

Download Full-text