1
|
Tantirukdham N, Sahakitrungruang T, Chaisiwamongkol R, Pongpanich M, Srichomthong C, Assawapitaksakul A, Buasong A, Tongkobpetch S, Yeetong P, Shotelersuk V. Long-read Amplicon Sequencing of the CYP21A2 in 48 Thai Patients With Steroid 21-Hydroxylase Deficiency. J Clin Endocrinol Metab 2022; 107:1939-1947. [PMID: 35363313 DOI: 10.1210/clinem/dgac187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT Congenital adrenal hyperplasia is most commonly caused by 21-hydroxylase deficiency (21-OHD), an autosomal recessive disorder resulting from biallelic pathogenic variants (PVs) in CYP21A2. With a highly homologous pseudogene and various types of single nucleotide and complex structural variants, identification of PVs in CYP21A2 has been challenging. OBJECTIVE To leverage long-read next-generation sequencing combined with locus-specific polymerase chain reaction (PCR) to detect PVs in CYP21A2 and to determine its diagnostic yield in patients with 21-OHD. METHODS Forty-eight Thai patients with 21-OHD comprising 38 sporadic cases and 5 pairs of siblings were enrolled. Two previously described locus-specific PCR methods were performed. Amplicons were subject to long-read sequencing. RESULTS Ninety-six PVs in CYP21A2 in the 48 patients were successfully identified. The combined techniques were able to detect 26 structural chimeric variants (27%; 26/96) in 22 patients with 18 having monoallelic and 4 having biallelic chimeras. The remaining PVs were pseudogene-derived mutations (63%; 60/96), entire gene deletions (2%; 2/96), missense variants (3%; 3/96), a splice-site variant (2%; 2/96), frameshift variants (2%; 2/96), and a nonsense variant (1%; 1/96). Notably, a splice-site variant, IVS7 + 1G > T, which was identified in a pair of siblings, has not previously been reported. CONCLUSIONS Our approach exploiting locus-specific PCR and long-read DNA sequencing has a 100% diagnostic yield for our cohort of 48 patients with 21-OHD.
Collapse
Affiliation(s)
- Nithiphut Tantirukdham
- Genetics Program, Division of Human Genetics, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
- Molecular and Genomics Research Laboratory, Chulabhorn Learning and Research Centre, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Taninee Sahakitrungruang
- Division of Pediatric Endocrinology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Ratikorn Chaisiwamongkol
- Division of Pediatric Endocrinology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Monnat Pongpanich
- Department of Mathematics and Computer Science, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
- Omics Sciences and Bioinformatics Center, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Chalurmpon Srichomthong
- Center of Excellence for Medical Genomics, Medical Genomics Cluster, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand
| | - Adjima Assawapitaksakul
- Center of Excellence for Medical Genomics, Medical Genomics Cluster, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand
| | - Aayalida Buasong
- Center of Excellence for Medical Genomics, Medical Genomics Cluster, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand
| | - Siraprapa Tongkobpetch
- Center of Excellence for Medical Genomics, Medical Genomics Cluster, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand
| | - Patra Yeetong
- Division of Human Genetics, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Vorasuk Shotelersuk
- Center of Excellence for Medical Genomics, Medical Genomics Cluster, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand
| |
Collapse
|
2
|
Carrozza C, Foca L, De Paolis E, Concolino P. Genes and Pseudogenes: Complexity of the RCCX Locus and Disease. Front Endocrinol (Lausanne) 2021; 12:709758. [PMID: 34394006 PMCID: PMC8362596 DOI: 10.3389/fendo.2021.709758] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 07/19/2021] [Indexed: 11/13/2022] Open
Abstract
Copy Number Variations (CNVs) account for a large proportion of human genome and are a primary contributor to human phenotypic variation, in addition to being the molecular basis of a wide spectrum of disease. Multiallelic CNVs represent a considerable fraction of large CNVs and are strictly related to segmental duplications according to their prevalent duplicate alleles. RCCX CNV is a complex, multiallelic and tandem CNV located in the major histocompatibility complex (MHC) class III region. RCCX structure is typically defined by the copy number of a DNA segment containing a series of genes - the serine/threonine kinase 19 (STK19), the complement 4 (C4), the steroid 21-hydroxylase (CYP21), and the tenascin-X (TNX) - lie close to each other. In the Caucasian population, the most common RCCX haplotype (69%) consists of two segments containing the genes STK19-C4A-CYP21A1P-TNXA-STK19B-C4B-CYP21A2-TNXB, with a telomere-to-centromere orientation. Nonallelic homologous recombination (NAHR) plays a key role into the RCCX genetic diversity: unequal crossover facilitates large structural rearrangements and copy number changes, whereas gene conversion mediates relatively short sequence transfers. The results of these events increased the RCCX genetic diversity and are responsible of specific human diseases. This review provides an overview on RCCX complexity pointing out the molecular bases of Congenital Adrenal Hyperplasia (CAH) due to CYP21A2 deficiency, CAH-X Syndrome and disorders related to CNV of complement component C4.
Collapse
Affiliation(s)
- Cinzia Carrozza
- Dipartimento di Scienze di Laboratorio e Infettivologiche, UOC Chimica, Biochimica e Biologia Molecolare Clinica, Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, Roma, Italy
- Dipartimento di Scienze Biotecnologiche di base, Cliniche Intensivologiche e Perioperatorie, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Laura Foca
- Dipartimento di Scienze di Laboratorio e Infettivologiche, UOC Chimica, Biochimica e Biologia Molecolare Clinica, Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, Roma, Italy
| | - Elisa De Paolis
- Dipartimento di Scienze di Laboratorio e Infettivologiche, UOC Chimica, Biochimica e Biologia Molecolare Clinica, Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, Roma, Italy
| | - Paola Concolino
- Dipartimento di Scienze di Laboratorio e Infettivologiche, UOC Chimica, Biochimica e Biologia Molecolare Clinica, Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, Roma, Italy
- *Correspondence: Paola Concolino,
| |
Collapse
|
3
|
Pignatelli D, Carvalho BL, Palmeiro A, Barros A, Guerreiro SG, Macut D. The Complexities in Genotyping of Congenital Adrenal Hyperplasia: 21-Hydroxylase Deficiency. Front Endocrinol (Lausanne) 2019; 10:432. [PMID: 31333583 PMCID: PMC6620563 DOI: 10.3389/fendo.2019.00432] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 06/17/2019] [Indexed: 12/13/2022] Open
Abstract
The deficiency of 21-hydroxylase due to CYP21A2 pathogenic variants is a rather frequent disease with serious consequences, going from a real mortality risk to infertility and to milder symptoms, nevertheless important for affecting the patients' self-esteem. In the most severe cases life-threatening adrenal salt wasting crises may occur. Significant morbidity including the possibility of mistaken gender determination, precocious puberty, infertility and growth arrest with consequent short stature may also affect these patients. In the less severe cases milder symptoms like hirsutism will likely affect the image of the self with strong psychological consequences. Its diagnosis is confirmed by 17OH-progesterone dosages exceeding the cut-off value of 10/15 ng/ml but genotyping is progressively assuming an essential role in the study of these patients particularly in confirming difficult cases, determining some aspects of the prognosis and allowing a correct genetic counseling. Genotyping is a difficult process due to the occurrence of both a gene and a highly homologous pseudo gene. However, new tools are opening new possibilities to this analysis and improving the chances of a correct diagnosis and better understanding of the underlying mechanisms of the disease. Beyond the 10 classic pathogenic variants usually searched for in most laboratories, a correct analysis of 21OH-deficiency cases implies completely sequencing of the entire gene and the determination of gene duplications. These are now recognized to occur frequently and can be responsible for some false positive cases. And finally, because gene conversions can include several pathogenic variants one cannot be certain of identifying that both alleles are affected without studying parental DNA samples. A complete genotype characterization should be considered essential in the preparation for pregnancy, even in the case of parents with milder forms of the disease, or even just carriers, since it has been reported that giving birth to progeny with the severe classic forms occurs with a much higher frequency than expected.
Collapse
Affiliation(s)
- Duarte Pignatelli
- Hospital S. João, Porto, Portugal
- Department of Biomedicine, Faculty of Medicine of Porto, Porto, Portugal
- IPATIMUP/I3S Research Institute, University of Porto, Porto, Portugal
- *Correspondence: Duarte Pignatelli
| | - Berta L. Carvalho
- Genetics, Department of Pathology, Faculty of Medicine, University of Porto, Porto, Portugal
- I3S Research Institute, University of Porto, Porto, Portugal
| | | | - Alberto Barros
- Genetics, Department of Pathology, Faculty of Medicine, University of Porto, Porto, Portugal
- I3S Research Institute, University of Porto, Porto, Portugal
| | - Susana G. Guerreiro
- Department of Biomedicine, Faculty of Medicine of Porto, Porto, Portugal
- IPATIMUP/I3S Research Institute, University of Porto, Porto, Portugal
| | - Djuro Macut
- Clinic of Endocrinology, Diabetes and Metabolic Diseases, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| |
Collapse
|
4
|
Congenital Adrenal Hyperplasia (CAH) due to 21-Hydroxylase Deficiency: A Comprehensive Focus on 233 Pathogenic Variants of CYP21A2 Gene. Mol Diagn Ther 2018; 22:261-280. [DOI: 10.1007/s40291-018-0319-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
5
|
Neocleous V, Fanis P, Phylactou LA, Skordis N. Genotype Is Associated to the Degree of Virilization in Patients With Classic Congenital Adrenal Hyperplasia. Front Endocrinol (Lausanne) 2018; 9:733. [PMID: 30559721 PMCID: PMC6286958 DOI: 10.3389/fendo.2018.00733] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 11/16/2018] [Indexed: 11/26/2022] Open
Abstract
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.
Collapse
Affiliation(s)
- Vassos Neocleous
- Department of Molecular Genetics, Function and Therapy, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
- Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Pavlos Fanis
- Department of Molecular Genetics, Function and Therapy, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
- Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Leonidas A. Phylactou
- Department of Molecular Genetics, Function and Therapy, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
- Cyprus School of Molecular Medicine, Nicosia, Cyprus
- *Correspondence: Nicos Skordis
| | - Nicos Skordis
- Department of Molecular Genetics, Function and Therapy, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
- Division of Pediatric Endocrinology, Paedi Center for Specialized Pediatrics, Nicosia, Cyprus
- St George's, University of London Medical School at the University of Nicosia, Nicosia, Cyprus
- Leonidas A. Phylactou
| |
Collapse
|
6
|
Ma D, Chen Y, Sun Y, Yang B, Cheng J, Huang M, Zhang J, Zhang J, Hu P, Lin Y, Jiang T, Xu Z. Molecular analysis of the CYP21A2 gene in Chinese patients with steroid 21-hydroxylase deficiency. Clin Biochem 2014; 47:455-63. [PMID: 24503005 DOI: 10.1016/j.clinbiochem.2014.01.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 01/16/2014] [Accepted: 01/20/2014] [Indexed: 11/26/2022]
Abstract
OBJECTIVE 21-Hydroxylase deficiency (21-OHD) is the most common cause of congenital adrenal hyperplasia (CAH), a family of autosomal recessive disorders involving impaired cortisol synthesis. This study aimed to design a reliable and rational approach for identifying mutations in the CYP21A2 gene and to characterize the molecular basis of 21-OHD in 30 Chinese patients. DESIGN AND METHODS Copy number variations were investigated by multiplex ligation-dependent probe amplification (MLPA). Locus-specific polymerase chain reaction (PCR)/restriction endonuclease analysis was then used to verify CYP21A2 rearrangement products and prevent allele dropout. Direct sequencing of rearrangement products was performed to further refine recombination breakpoint locations. Direct sequencing of the entire CYP21A2 gene was used to detect microconversions. RESULTS We successfully characterized 60 CYP21A2 alleles from 30 patients with genetic defects. The most common one was intron 2 splice mutation (38.3%). Eighteen alleles with large gene deletions/conversions were identified, which accounted for nearly one-third (30.0%) of the genetic defects. Among these, three types of CYP21A1P/CYP21A2 chimeric genes (CH-1, CH-2, and CH-4) were characterized. Two novel CYP21A2 rearrangement genes were revealed and further demonstrated to be located downstream of the TNXB gene. CONCLUSIONS Our results indicate that the stepwise diagnostic procedure involving MLPA analysis, locus-specific PCR/restriction endonuclease analysis, and direct DNA sequencing can provide detailed genetic information about Chinese 21-OHD patients, which is helpful for characterizing structural rearrangements of CYP21A2.
Collapse
Affiliation(s)
- Dingyuan Ma
- State Key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing 210029, China
| | - Yulin Chen
- State Key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing 210029, China
| | - Yun Sun
- State Key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing 210029, China
| | - Bing Yang
- State Key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing 210029, China
| | - Jian Cheng
- State Key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing 210029, China
| | - Meilian Huang
- State Key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing 210029, China
| | - Jin Zhang
- State Key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing 210029, China
| | - Jingjing Zhang
- State Key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing 210029, China
| | - Ping Hu
- State Key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing 210029, China
| | - Ying Lin
- State Key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing 210029, China
| | - Tao Jiang
- State Key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing 210029, China.
| | - Zhengfeng Xu
- State Key Laboratory of Reproductive Medicine, Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing 210029, China.
| |
Collapse
|
7
|
Comprehensive mutation analysis of the CYP21A2 gene: an efficient multistep approach to the molecular diagnosis of congenital adrenal hyperplasia. J Mol Diagn 2013; 15:745-53. [PMID: 24071710 DOI: 10.1016/j.jmoldx.2013.06.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 05/13/2013] [Accepted: 06/11/2013] [Indexed: 11/21/2022] Open
Abstract
Congenital adrenal hyperplasia, due to 21-hydroxylase deficiency (21-OHD) is an autosomal recessive disorder of adrenal steroidogenesis caused by mutations in the CYP21A2 gene. Direct comparison of established and novel methodologies of CYP21A2 genetic analysis in a large cohort representing a wide range of genotypes has not been previously reported. We genotyped a cohort of 129 unrelated patients with 21-OHD, along with 145 available parents, using Southern blot (SB) analysis, multiplex ligation-dependent probe amplification (MLPA), PCR-based restriction fragment length polymorphism (RFLP) analysis, multiplex minisequencing and conversion-specific PCR, duplication-specific amplification, and DNA sequencing. CYP21A2 genotyping identified four duplicated CYP21A2 genes (1.53%) and 79 chimeric CYP21A1P/CYP21A2 genes (30.15%). Parental SB data were essential for determining the CYP21 haplotype in three cases, whereas PCR-based RFLP analysis was necessary for MLPA results to be accurately interpreted in the majority of cases. The comparison of different methods in detecting deletion and duplication showed that MLPA with PCR-based RFLP was comparable with SB analysis, with parental data of 100% sensitivity and specificity. DNA sequencing was required for the identification of 16 (6.1%) rare point mutations and determination of clinically significant chimera junction sites. MLPA with PCR-based RFLP analysis is an excellent substitute for SB analysis in detecting CYP21A2 deletion and duplication and a combination of MLPA, PCR-based RFLP, duplication-specific amplification, and DNA sequencing is a convenient and comprehensive strategy for mutation analysis of the CYP21A2 gene in patients with 21-OHD.
Collapse
|
8
|
Balraj P, Lim PG, Sidek H, Wu LL, Khoo ASB. Mutational characterization of congenital adrenal hyperplasia due to 21-hydroxylase deficiency in Malaysia. J Endocrinol Invest 2013; 36:366-74. [PMID: 23027774 DOI: 10.3275/8648] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND AND AIM Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD) is a common autosomal recessive disorder. Our objective was to identify the 21-hydroxylase active gene, CYP21A2 mutations in Malaysian 21-OHD patients using different techniques. MATERIALS AND METHODS Blood samples were obtained from 97 Malaysian 21-OHD patients, which included 40 siblings from 19 families. We used various techniques which include restriction enzyme digestion, Southern blot, multiple ligation-dependent probe amplification (MLPA) and sequencing to elucidate CYP21A2 mutations. RESULTS Homozygous and compound heterozygous mutations were identified in 95 of the 97 patients (98%). Deletions of CYP21A2 were found in 43 patients (44.3%). Deletions identified in CYP21A2 gene were the usual 30-kb deletion comprising 3'UTR CYP21A1P, C4B and 5'CYP21A2, complete deletion of CYP21A2 gene, deletion in exons 1-3, exons 1-6 and exons 1-8 of CYP21A2. The common mutations identified in CYP21A2 gene were deletion/conversion (22.6%), p.R356W (22%), IVS2-13A/C>G (21.3%), p.I172N (5.3%), p.Q318X (5.3%), and p.P30L (1.03%). This is the first report of the mutation frequency in CYP21A2 gene among the Malay ethnic group. Two novel mutations, c.Y97insT and p.L345P were identified in our patients. Our results show good phenotype-genotype correlation in most of the cases, although clinical variations were identified in some patients. CONCLUSIONS The study has found various mutations including deletions in CYP21A2 gene in Malaysian patients with 21-hydroxylase deficiency using the MLPA technique that is being widely used in present laboratory settings.
Collapse
Affiliation(s)
- P Balraj
- Molecular Pathology Unit, Institute for Medical Research, Jln Pahang, Kuala Lumpur, Malaysia.
| | | | | | | | | |
Collapse
|
9
|
Lee HH. Variants of the CYP21A2 and CYP21A1P genes in congenital adrenal hyperplasia. Clin Chim Acta 2013; 418:37-44. [DOI: 10.1016/j.cca.2012.12.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 12/30/2012] [Accepted: 12/31/2012] [Indexed: 10/27/2022]
|
10
|
Chen W, Xu Z, Sullivan A, Finkielstain GP, Van Ryzin C, Merke DP, McDonnell NB. Junction site analysis of chimeric CYP21A1P/CYP21A2 genes in 21-hydroxylase deficiency. Clin Chem 2011; 58:421-30. [PMID: 22156666 DOI: 10.1373/clinchem.2011.174037] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Chimeric CYP21A1P/CYP21A2 genes, caused by homologous recombination between CYP21A2 (cytochrome P450, family 21, subfamily A, polypeptide 2) and its highly homologous pseudogene CYP21A1P (cytochrome P450, family 21, subfamily A, polypeptide 1 pseudogene), are common in patients with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD). A comprehensive junction site analysis of chimeric CYP21A1P/CYP21A2 genes is needed for optimizing genetic analysis strategy and determining clinical relevance. METHODS We conducted a comprehensive genetic analysis of chimeric CYP21A1P/CYP21A2 genes in a cohort of 202 unrelated 21-OHD patients. Targeted CYP21A2 mutation analysis was performed, and genotyping of chimeric CYP21A1P/CYP21A2 genes was cross-confirmed with Southern blot, RFLP, and multiplex ligation-dependent probe amplification analyses. Junction sites of chimera genes were determined by sequencing the long-PCR products amplified with primers CYP779f and Tena32F. An updated bioinformatics survey of Chi-like sequences was also performed. RESULTS Of 100 probands with a chimeric allele, 96 had a chimera associated with the severe classic salt-wasting form of CAH, and the remaining 4 carried an uncommon attenuated chimera with junction sites upstream of In2G (c.293-13A/C>G), which is associated with a milder phenotype. In addition to 6 of 7 reported chimeras, we identified a novel classic chimera (CH-8) and a novel attenuated chimera (CH-9). Attenuated chimeras explained prior genotype-phenotype discrepancies in 3 of the patients. Sequencing the CYP779f/Tena32F amplicons accurately differentiated between classic and attenuated chimeras. The bioinformatics survey revealed enrichment of Chi-like sequences within or in the vicinity of intron 2. CONCLUSIONS Junction site analysis can explain some genotype-phenotype discrepancies. Sequencing the well-established CYP779f/Tena32F amplicons is an unequivocal strategy for detecting attenuated chimeric CYP21A1P/CYP21A2 genes, which are clinically relevant.
Collapse
Affiliation(s)
- Wuyan Chen
- Laboratory of Clinical Investigation, National Institute on Aging, Baltimore, MD 21224, USA
| | | | | | | | | | | | | |
Collapse
|
11
|
Chang SF, Lee HH. Analysis of the CYP21A2 Gene with Intergenic Recombination and Multiple Gene Deletions in the RCCX Module. Genet Test Mol Biomarkers 2011; 15:35-42. [PMID: 21117955 DOI: 10.1089/gtmb.2010.0080] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Shwu-Fen Chang
- Graduate Institute of Cell and Molecular Biology, Taipei Medical University, Taipei, Taiwan
| | - Hsien-Hsiung Lee
- School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan
| |
Collapse
|
12
|
Vrzalová Z, Hrubá Z, Hrabincová ES, Vrábelová S, Votava F, Koloušková S, Fajkusová L. Chimeric CYP21A1P/CYP21A2 genes identified in Czech patients with congenital adrenal hyperplasia. Eur J Med Genet 2010; 54:112-7. [PMID: 20970527 DOI: 10.1016/j.ejmg.2010.10.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2010] [Accepted: 10/13/2010] [Indexed: 11/30/2022]
Abstract
Congenital adrenal hyperplasia (CAH) comprises a group of autosomal recessive disorders caused by an enzymatic deficiency which impairs the biosynthesis of cortisol and, in the majority of severe cases, also the biosynthesis of aldosterone. Approximately 95% of all CAH cases are caused by mutations in the steroid 21-hydroxylase gene (CYP21A2). The CYP21A2 gene and its inactive pseudogene (CYP21A1P) are located within the HLA class III region of the major histocompatibility complex (MHC) locus on chromosome 6p21.3. In this study, we describe chimeric CYP21A1P/CYP21A2 genes detected in our patients with 21-hydroxylase deficiency (21OHD). Chimeric CYP21A1P/CYP21A2 genes were present in 171 out of 508 mutated CYP21A2 alleles (33.8%). We detected four types of chimeric CYP21A1P/CYP21A2 genes: three of them have been described previously as CH-1, CH-3, CH-4, and one type is novel. The novel chimeric gene, termed CH-7, was detected in 21.4% of the mutant alleles. Possible causes of CYP21A1P/CYP21A2 formation are associated with 1) high recombination rate in the MHC locus, 2) high recombination rate between highly homologous genes and pseudogenes in the CYP21 gene area, and 3) the existence of chi-like sequences and repetitive minisatellite consensus sequences in CYP21A2 and CYP21A1P which play a role in promoting genetic recombination.
Collapse
Affiliation(s)
- Zuzana Vrzalová
- University Hospital Brno, Centre of Molecular Biology and Gene Therapy, Czech Republic
| | | | | | | | | | | | | |
Collapse
|
13
|
Concolino P, Mello E, Zuppi C, Capoluongo E. Molecular diagnosis of congenital adrenal hyperplasia due to 21-hydroxylase deficiency: an update of new CYP21A2 mutations. Clin Chem Lab Med 2010; 48:1057-62. [DOI: 10.1515/cclm.2010.239] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
14
|
Concolino P, Mello E, Minucci A, Giardina E, Zuppi C, Toscano V, Capoluongo E. A new CYP21A1P/CYP21A2 chimeric gene identified in an Italian woman suffering from classical congenital adrenal hyperplasia form. BMC MEDICAL GENETICS 2009; 10:72. [PMID: 19624807 PMCID: PMC2718876 DOI: 10.1186/1471-2350-10-72] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Accepted: 07/22/2009] [Indexed: 12/01/2022]
Abstract
Background More than 90% of Congenital Adrenal Hyperplasia (CAH) cases are associated with mutations in the 21-hydroxylase gene (CYP21A2) in the HLA class III area on the short arm of chromosome 6p21.3. In this region, a 30 kb deletion produces a non functional chimeric gene with its 5' and 3' ends corresponding to CYP21A1P pseudogene and CYP21A2, respectively. To date, five different CYP21A1P/CYP21A2 chimeric genes have been found and characterized in recent studies. In this paper, we describe a new CYP21A1P/CYP21A2 chimera (CH-6) found in an Italian CAH patient. Methods Southern blot analysis and CYP21A2 sequencing were performed on the patient. In addition, in order to isolate the new CH-6 chimeric gene, two different strategies were used. Results The CYP21A2 sequencing analysis showed that the patient was homozygote for the g.655C/A>G mutation and heterozygote for the p.P30L missense mutation. In addition, the promoter sequence revealed the presence, in heterozygosis, of 13 SNPs generally produced by microconversion events between gene and pseudogene. Southern blot analysis showed that the woman was heterozygote for the classic 30-kb deletion producing a new CYP21A1P/CYP21A2 chimeric gene (CH-6). The hybrid junction site was located between the end of intron 2 pseudogene, after the g.656C/A>G mutation, and the beginning of exon 3, before the 8 bp deletion. Consequently, CH-6 carries three mutations: the weak pseudogene promoter region, the p.P30L and the g.655C/A>G splice mutation. Conclusion We describe a new CYP21A1P/CYP21A2 chimera (CH-6), associated with the HLA-B15, DR13 haplotype, in a young Italian CAH patient.
Collapse
Affiliation(s)
- Paola Concolino
- Laboratory of Molecular Biology, Institute of Biochemistry and Clinical Biochemistry, Catholic University, Largo A, Gemelli 8, 00168 Rome, Italy.
| | | | | | | | | | | | | |
Collapse
|
15
|
Multiplex ligation-dependent probe amplification (MLPA) assay for the detection of CYP21A2 gene deletions/duplications in congenital adrenal hyperplasia: first technical report. Clin Chim Acta 2009; 402:164-70. [PMID: 19263525 DOI: 10.1016/j.cca.2009.01.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND More than 90% of the cases of Congenital Adrenal Hyperplasia (CAH) are associated with mutations in 21-hydroxylase gene (CYP21A2). Up to now, large CYP21A2 rearrangements have been mainly detected by Southern blot analysis, although more rapid methods have been alternatively proposed. In this paper, we report the use of a multiplex ligation-dependent probe amplification (MLPA) method for easy and rapid detection of deletions/duplications in the CYP21A2 gene. METHODS We collected 18 CAH Italian patients previously analyzed by gene sequencing and Southern blot technique. In addition, a prenatal diagnosis study was performed. RESULTS Of the 7 known subjects with CYP21A2 deletions and 2 with gene duplications previously characterized in our laboratory, all were successfully identified by the MLPA analysis. In the prenatal diagnosis study, the MLPA assay was able to identify the presence of a CYP21A2 gene duplication in the fetus, as well in other two family members. CONCLUSION MLPA analysis represents a simple, rapid and sensitive tool for the detection of CYP21A2/CYP21A1P deletions/duplications in CAH molecular diagnosis. Compared to Southern blot, MLPA may be considered a high throughput analysis, allowing the simultaneous study of several samples in the same experiment and the investigation of both gene (CYP21A2) and pseudogene (CYP21A1P) in each patient.
Collapse
|
16
|
Parajes S, Quinterio C, Domínguez F, Loidi L. A simple and robust quantitative PCR assay to determine CYP21A2 gene dose in the diagnosis of 21-hydroxylase deficiency. Clin Chem 2007; 53:1577-84. [PMID: 17634211 DOI: 10.1373/clinchem.2007.087361] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Correct diagnosis of 21-hydroxylase deficiency (21OHD) requires the identification of CYP21A2 gene deletions and CYP21A1P/CYP21A2 chimeric genes, which are disease-causing alleles, and gene duplications, which can lead to false-positive 21OHD allele results. Because lack of suitable CYP21A2 dosage assessment methods hampers correct 21OHD diagnosis, we developed a new assay based on the relative quantification of the CYP21A2 gene using the DSP gene as a reference. METHODS The assay to determine CYP21A2 copy number is based on real-time PCR. The method also detects the presence of the CYP21A1P/CYP21A2 chimeric gene. We used a duplex PCR to coamplify the DSP gene, included as an internal control, along with CYP21A2. The difference in threshold cycles between CYP21A2 and DSP genes (DeltaCt) was used to assess CYP21A2 copy number. RESULTS The DeltaCt values obtained from 24 samples used to set up the method clearly differentiated 3 nonoverlapping intervals, which corresponded to the number of CYP21A2 copies: -1.35 to -0.25 defined 2 gene copies, +0.20 to +2.00 defined 1 copy, and -2.50 to -1.50 defined 3 copies. With these intervals we were able to assess the gene copy number in 24 additional samples. CONCLUSIONS This new method for gene copy assessment detects homozygous and heterozygous CYP21A2 gene deletions, CYP21A1P/CYP21A2 chimeric genes, and gene duplications. Moreover, the method is robust, fast, and easy to use in a molecular diagnosis laboratory. This method together with CYP21A2 gene sequencing can provide a definitive system for the detection of almost all, common as well as rare, 21OHD alleles.
Collapse
Affiliation(s)
- Silvia Parajes
- Fundación Pública Gallega de Medicina Genómica (Unidad de Medicina Molecular), Santiago de Compostela, Spain
| | | | | | | |
Collapse
|
17
|
Abstract
More than 90% of cases of congenital adrenal hyperplasia (CAH) are caused by mutations of the CYP21 gene. The occurrence of defective CYP21 genes, including 15 mutations, has been attributed to intergenic recombination of DNA sequences from CYP21P, and shows no influence on the RP1-C4A-CYP21P-XA-RP2-C4BCYP21- TNXB gene locus on chromosome 6p21.3. However, multiple gene deletions in this region produce at least three categories of gene arrangements: (a) C4A-CYP21P/CYP21-TNXB, in which there is a CYP21P/CYP21 fusion gene; (b) C4A-XCYP21-TNXB, where XCYP21 indicates that the CYP21 gene contains mutations of IVS2 (-12A/C>G and 707-714delGAGACTAC); and (c) C4A-CYP21P-TNXA/TNXB, in which the TNX A and B genes are fused. Among them, seven different structures of the CYP21 haplotype were found at these three loci. Formation of the C4A-CYP21P/CYP21-TNXB locus produced four distinct CYP21P/CYP21 chimeras. The C4A-XCYP21-TNXB locus contained the IVS2 mutation -12A/C>G and 707-714delGAGACTAC from the XCYP21 gene; and two kinds of TNXA/TNXB hybrids were found in the C4A-CYP21P-TNXA/TNXB locus. The seven different CYP21 alleles produced 3.2 kb Taq I fragments caused by deletion of the RP2-XA-C4B locus. Therefore, production of a 3.2-kb CYP21 allele shows diversity, but is not a unique feature of the CYP21P gene. Most of these gene arrangements probably exist in the C4A-XCYP21-TNXB and C4A-CYP21P/CYP21-TNXB gene loci. The existence of the C4A-CYP21P-TNXA/TNXB locus might not be common in CAH patients with 21-hydroxylase deficiency.
Collapse
Affiliation(s)
- Hsien-Hsiung Lee
- King Car Food Industrial Co., Yuan-Shan Research Institute, Taiwan, Republic of China.
| |
Collapse
|
18
|
Lee HH, Lee YJ, Chan P, Lin CY. Use of PCR-based amplification analysis as a substitute for the southern blot method for CYP21 deletion detection in congenital adrenal hyperplasia. Clin Chem 2004; 50:1074-6. [PMID: 15161727 DOI: 10.1373/clinchem.2003.028597] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hsien-Hsiung Lee
- King Car Food Industrial Co., Yuan-Shan Research Institute, Taiwan, Republic of China.
| | | | | | | |
Collapse
|
19
|
Lee HH. The chimeric CYP21P/CYP21 gene and 21-hydroxylase deficiency. J Hum Genet 2004; 49:65-72. [PMID: 14730433 DOI: 10.1007/s10038-003-0115-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2003] [Accepted: 11/18/2003] [Indexed: 10/26/2022]
Abstract
The chimeric CYP21P/CYP21 gene is a consequence of a 26- or 32-kb deletion in the C4-CYP21 repeat module of CYP21P, tenascin A ( XA), serine/threonine nuclear protein kinase ( RP2), and the C4B and CYP21 genes in congenital adrenal hyperplasia (CAH) with steroid 21-hydroxylase deficiency. To date, there have been three distinct chimeras found in CAH patients in ethnic Chinese. Initiation for production of these molecules is proposed to be chi-like sequences and a minisatellite consensus existing in several noncoding regions in CYP21 genes. These molecules have the 5' end of the CYP21P-specific sequence in common but differ in the 3' end of CYP21-specific genes. In addition, there appears to be a 3.2-kb fragment generated by Taq I digestion, which leads to allele dropout in PCR amplification for detecting the aberrant splicing site of the IVS2 -12A/C>G mutation at nucleotide (nt) 655 in the CYP21 gene. Therefore, the chimeric CYP21P/CYP21 cannot be detected by conventional methods. It has been demonstrated that a PCR product amplified with allele-specific primers covering tenascin B ( TNXB) to the 5' end of the CYP21 gene combined with Southern analysis by Ase I and Nde I digestion may be used for identifying the chimera in the CYP21 gene.
Collapse
Affiliation(s)
- Hsien-Hsiung Lee
- King Car Food Industrial Co., Yuan-Shan Research Institute, 326 Yuan-Shan Road, Sec. 2, Yuanshan, 264, Ilan, Taiwan, Republic of China.
| |
Collapse
|
20
|
|
21
|
Lee HH, Chang SF, Lo FS, Chao HT, Lin CY. Duplication of 111 bases in exon 1 of the CYP21 gene is combined with deletion of CYP21P-C4B genes in steroid 21-hydroxylase deficiency. Mol Genet Metab 2003; 79:214-20. [PMID: 12855227 DOI: 10.1016/s1096-7192(03)00087-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Congenital adrenal hyperplasia (CAH) is a common autosomal recessive disorder mainly caused by defects in the steroid 21-hydroxylase (CYP21) gene. A 9.3-kb fragment generated by NdeI and AseI digestion by Southern blot analysis indicated that a consequence of deletion of the C4-CYP21 repeat module was the production of a distinct chimeric CYP21P/CYP21 molecule. In the present study, we report a novel CYP21 genotype in two CAH families in which the gene appeared as 9.4- and 3.3-kb fragments by TaqI digestion, rather than as a chimeric gene. From the analysis of PCR amplification patterns and DNA sequencing, we found that there was a duplication of 111 bases from codons 21 to 57 inserted at codon 58 in exon 1 of the CYP21 gene. In addition, codon 21 in the repeated sequence changed from TGG to AGG. Furthermore, this novel CYP21 gene present in both CAH families showed no mutations at IVS2-12A/C>G, 707-714delGAGACTAC, and P30L. Interestingly, the 5' end region of these two CYP21 genes showed the sequence of the CYP21P gene at nucleotides (nt) -103, -110, -123, and thereafter. Our data suggest that these two CYP21 genes are caused by deletion of the CYP21P, XA, RP2, and C4B genes. Possibly, the additional 111-base duplicated coding sequence may be generated by multiple intergenic recombinations, while there seems to be no relationship with deletion of the CYP21P-C4B regions.
Collapse
Affiliation(s)
- Hsien-Hsiung Lee
- King Car Food Industrial Co., Yuan-Shan Research Institute, No. 326 Yuan Shan Rd., Sec. 2, Yuan Shan, Ilan 264, Taiwan, Republic of China.
| | | | | | | | | |
Collapse
|
22
|
Lee HH, Chang SF, Tsai FJ, Tsai LP, Lin CY. 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. J Clin Endocrinol Metab 2003; 88:2726-9. [PMID: 12788880 DOI: 10.1210/jc.2003-030047] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
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.
Collapse
Affiliation(s)
- Hsien-Hsiung Lee
- King Car Food Industrial Co., Yuan-Shan Research Institute, Ilan 264, Taiwan, Republic of China.
| | | | | | | | | |
Collapse
|