Multiplex ligation-dependent probe amplification (MLPA) assay for the detection of CYP21A2 gene deletions/duplications in Congenital Adrenal Hyperplasia: First technical report

Congenital adrenal hyperplasia is a group of autosomal recessive disorders. The most frequent one is 21-hydroxylase deficiency. Analyzing CYP21A2 gene mutations was so far not reported in Iraq. This work aims to analyze the spectrum and frequency of CYP21A2 mutations among Iraqi CAH patients. Sixty-two children were recruited from the Pediatric Endocrine Consultation Clinic, Children Welfare Teaching Hospital, Baghdad, Iraq, from September 2014 till June 2015. Their ages ranged between one day and 15 years. They presented with salt wasting, simple virilization, or pseudoprecocious puberty. Cytogenetic study was performed for cases with ambiguous genitalia. Molecular analysis of CYP21A2 gene was done using the CAH StripAssay (ViennaLab Diagnostics) for detection of 11 point mutations and >50% of large gene deletions/conversions. Mutations were found in 42 (67.7%) patients; 31 (50%) patients were homozygotes, 9 (14.5%) were heterozygotes, and 2 (3.2%) were compound heterozygotes with 3 mutations, while 20 (32.3%) patients had none of the tested mutations. The most frequently detected mutations were large gene deletions/conversions found in 12 (19.4%) patients, followed by I2Splice and Q318X in 8 (12.9%) patients each, I172N in 5 (8.1%) patients, and V281L in 4 (6.5%) patients. Del 8 bp, P453S, and R483P were each found in one (1.6%) and complex alleles were found in 2 (3.2%). Four point mutations (P30L, Cluster E6, L307 frameshift, and R356W) were not identified in any patient. In conclusion, gene deletions/conversions and 7 point mutations were recorded in varying proportions, the former being the commonest, generally similar to what was reported in regional countries.

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Phenotype and genotype correlation of the microconversion from the CYP21A1P to the CYP21A2 gene in congenital adrenal hyperplasia

Brazilian Journal of Medical and Biological Research ◽

10.1590/s0100-879x2003001000006 ◽

2003 ◽

Vol 36 (10) ◽

pp. 1311-1318 ◽

Cited By ~ 23

Author(s):

N. Torres ◽

M.P. Mello ◽

C.M.R. Germano ◽

L.L.K. Elias ◽

A.C. Moreira ◽

...

Keyword(s):

Congenital Adrenal Hyperplasia ◽

Adrenal Hyperplasia ◽

Cyp21a2 Gene ◽

Genotype Correlation

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ID: 1048 A novel nonsense mutation in the CYP21A2 gene of a Vietnamese patient with congenital adrenal hyperplasia

Biomedical Research and Therapy ◽

10.15419/bmrat.v4is.324 ◽

2017 ◽

Vol 4 (S) ◽

pp. 129

Author(s):

Vu Chi Dung ◽

Ngoc Lan Nguyen ◽

Huy Hoang Nguyen ◽

Thi Kim Lien Nguyen ◽

Thinh Huy Tran ◽

...

Keyword(s):

Congenital Adrenal Hyperplasia ◽

Nonsense Mutation ◽

Stop Codon ◽

Large Deletion ◽

Heterozygous Mutation ◽

Normal Allele ◽

Adrenal Hyperplasia ◽

Steroid Synthesis ◽

Cyp21a2 Gene ◽

Exon 1

Inactivating mutations in the CYP21A2 gene which encodes the protein involved in steroid synthesis have been reported in the patients with congenital adrenal hyperplasia (CAH). An infant who diagnosed with the severe phenotype of CAH such as increasing testicular volume, elevating of 17-hydroxyprogesteron, testosterone and progesterone and his family were subjected for genetic studies. Initially, we used PCR and direct sequencing to screen mutations in the CYP21 gene in the proband and his family. We identified a novel nonsense mutation c.374C>G predicts a substitution of serine for a stop codon at codon 125 (p.S125*) within exon 3 in the proband. However, the inheritance pattern of the mutation was not consistent with disease causation because of a heterozygous mutation carrier in father and sibling, wild-type alleles in mother but mutant alleles in proband. This inspired us to find deletions of exon using multiplex ligation-dependent probe amplification (MLPA) assay. In the profiles of MLPA electropherogram, the proband had a large deletion in exon 3, but his mother did not have. It means that the proband inherited a normal allele from his mother and a mutant allele from his father, but the deletion of a normal allele occurred in the proband. Therefore, mutation c.374C>G (p.S125*) in exon 3 in the proband is considered as a heterozygous deletion mutation. In addition, a large deletion in exon 1 in the maternal allele in the proband is observed. Taking together, the proband carried a nonsense mutation accompanied with two deletions in exon 1 and exon 3 in the CYP21A2 gene affect the CAH phenotype severity. These mutations also expand the CYP21A2 mutation spectrum in CAH disorder. This case also highlights the need of caution when interpreting results of molecular genetics and biochemical testing during genetic counseling.

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Molecular Analysis of CYP21A2 Gene Mutations among Congenital Adrenal Hyperplasia Patients in Iraq

Challenges in Disease and Health Research Vol. 10 ◽

10.9734/bpi/cdhr/v10/10410d ◽

2021 ◽

pp. 82-92

Author(s):

Ruqayah G. Y. Al-Obaidi ◽

Bassam M. S. Al-Musawi ◽

Munib Ahmed K. AlZubaidi ◽

Christian Oberkanins ◽

Stefan Németh ◽

...

Keyword(s):

Congenital Adrenal Hyperplasia ◽

Molecular Analysis ◽

Gene Mutations ◽

Adrenal Hyperplasia ◽

Cyp21a2 Gene

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Clinical application of a novel next generation sequencing assay for CYP21A2 gene in 310 cases of 21- hydroxylase congenital adrenal hyperplasia from India

Endocrine ◽

10.1007/s12020-020-02494-z ◽

2020 ◽

Author(s):

Priyanka Gangodkar ◽

Vaman Khadilkar ◽

P. Raghupathy ◽

Rakesh Kumar ◽

Archana Arya Dayal ◽

...

Keyword(s):

Next Generation Sequencing ◽

Congenital Adrenal Hyperplasia ◽

Clinical Application ◽

Next Generation ◽

Adrenal Hyperplasia ◽

Cyp21a2 Gene ◽

Generation Sequencing

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Tenascin-X, Congenital Adrenal Hyperplasia, and the CAH-X Syndrome

Hormone Research in Paediatrics ◽

10.1159/000481911 ◽

2018 ◽

Vol 89 (5) ◽

pp. 352-361 ◽

Cited By ~ 12

Author(s):

Walter L. Miller ◽

Deborah P. Merke

Keyword(s):

Congenital Adrenal Hyperplasia ◽

Matrix Protein ◽

Connective Tissue Disorder ◽

Joint Hypermobility ◽

Extracellular Matrix Protein ◽

Adrenal Hyperplasia ◽

Full Spectrum ◽

Ehlers Danlos Syndrome ◽

Cyp21a2 Gene ◽

Salt Wasting

Mutations of the CYP21A2 gene encoding adrenal 21-hydroxylase cause congenital adrenal hyperplasia (CAH). The CYP21A2 gene is partially overlapped by the TNXB gene, which encodes an extracellular matrix protein called Tenascin-X (TNX). Mutations affecting both alleles of TNXB cause a severe, autosomal recessive form of Ehlers-Danlos syndrome (EDS). Rarely, patients with severe, salt-wasting CAH have deletions of CYP21A2 that extend into TNXB, resulting in a “contiguous gene syndrome” consisting of CAH and EDS. Heterozygosity for TNXB mutations causing haploinsufficiency of TNX may be associated with the mild “hypermobility form” of EDS, which principally affects small and large joints. Studies of patients with salt-wasting CAH found that up to 10% had clinical features of EDS, associated joint hypermobility, haploinsufficiency of TNX and heterozygosity for TNXB mutations, now called “CAH-X.” These patients have joint hypermobility and a spectrum of other comorbidities associated with their connective tissue disorder, including chronic arthralgia, joint subluxations, hernias, and cardiac defects. Other disorders are beginning to be associated with TNX deficiency, including familial vesicoureteral reflux and neurologic disorders. Further work is needed to delineate the full spectrum of TNX-deficient disorders, with and without associated CAH.

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Detection of a novel severe mutation affecting the CYP21A2 gene in a Chilean male with salt wasting congenital adrenal hyperplasia

Endocrine ◽

10.1007/s12020-019-02097-3 ◽

2019 ◽

Vol 67 (1) ◽

pp. 258-263

Author(s):

Eugenio Arteaga ◽

Felipe Valenzuela ◽

Carlos F. Lagos ◽

Marcela Lagos ◽

Alejandra Martinez ◽

...

Keyword(s):

Congenital Adrenal Hyperplasia ◽

Adrenal Hyperplasia ◽

Cyp21a2 Gene ◽

Salt Wasting ◽

Severe Mutation

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P450XXI (steroid 21-hydroxylase) gene deletions are not found in family studies of congenital adrenal hyperplasia.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.84.16.5858 ◽

1987 ◽

Vol 84 (16) ◽

pp. 5858-5862 ◽

Cited By ~ 42

Author(s):

K. J. Matteson ◽

J. A. Phillips ◽

W. L. Miller ◽

B. C. Chung ◽

P. J. Orlando ◽

...

Keyword(s):

Congenital Adrenal Hyperplasia ◽

Family Studies ◽

Adrenal Hyperplasia ◽

Gene Deletions ◽

Hydroxylase Gene

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Molecular genetic strategy for diagnosis of congenital adrenal hyperplasia in Serbia

Genetika ◽

10.2298/gensr1702457u ◽

2017 ◽

Vol 49 (2) ◽

pp. 457-467 ◽

Cited By ~ 1

Author(s):

Milena Ugrin ◽

Iva Milacic ◽

Anita Skakic ◽

Kristel Klaassen ◽

Jovana Komazec ◽

...

Keyword(s):

Genetic Testing ◽

Congenital Adrenal Hyperplasia ◽

Direct Sequencing ◽

Molecular Genetic ◽

Gene Rearrangements ◽

Molecular Genetic Testing ◽

Adrenal Hyperplasia ◽

Cyp21a2 Gene ◽

Classical Form ◽

Large Gene

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.

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