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Batista RL, Mendonca BB. The Molecular Basis of 5α-Reductase Type 2 Deficiency. Sex Dev 2022; 16:171-183. [PMID: 35793650 DOI: 10.1159/000525119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 05/13/2022] [Indexed: 11/19/2022] Open
Abstract
The 5α-reductase type 2 enzyme catalyzes the conversion of testosterone into dihydrotestosterone, playing a crucial role in male development. This enzyme is encoded by the SRD5A2 gene, which maps to chromosome 2 (2p23), consists of 5 exons and 4 introns, and encodes a 254 amino acid protein. Disruptions in this gene are the molecular etiology of a subgroup of differences of sex development (DSD) in 46,XY patients. Affected individuals present a large range of external genitalia undervirilization, ranging from almost typically female external genitalia to predominantly typically male external genitalia with minimal undervirilization, including isolated micropenis. This is an updated review of the implication of the SRD5A2 gene in 5α-reductase type 2 enzyme deficiency. For that, we identified 451 cases from 48 countries of this particular 46,XY DSD from the literature with reported variants in the SRD5A2 gene. Herein, we present the SRD5A2 mutational profile, the SRD5A2 polymorphisms, and the functional studies related to SRD5A2 variants to detail the molecular etiology of this condition.
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Affiliation(s)
- Rafael L Batista
- Unidade de Endocrinologia do Desenvolvimento, Laboratório de Hormônios e Genética Molecular/LIM42, Hospital das Clínicas, Disciplina de Endocrinologia, do Departamento de Clínica Médica, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.,Endocrine Oncology Unit, Instituto do Câncer do Estado de São Paulo, ICESP, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Berenice B Mendonca
- Unidade de Endocrinologia do Desenvolvimento, Laboratório de Hormônios e Genética Molecular/LIM42, Hospital das Clínicas, Disciplina de Endocrinologia, do Departamento de Clínica Médica, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
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Batista RL, Mendonca BB. Integrative and Analytical Review of the 5-Alpha-Reductase Type 2 Deficiency Worldwide. APPLICATION OF CLINICAL GENETICS 2020; 13:83-96. [PMID: 32346305 PMCID: PMC7167369 DOI: 10.2147/tacg.s198178] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 02/20/2020] [Indexed: 12/12/2022]
Abstract
Introduction The conversion of testosterone into dihydrotestosterone is catalyzed by the 5α-reductase type 2 enzyme which plays a crucial role in the external genitalia virilization. It is encoded by the SRD5A2 gene. Allelic variants in this gene cause a 46,XY DSD with no genotype-phenotype relationship. It was firstly reported in the early 70s from isolated clusters. Since then, several cases have been reported. Putting together, it will expand the knowledge on the molecular bases of androgen milieu. Methods We searched for SRD5A2 allelic variants (AV) in the literature (PubMed, Embase, MEDLINE) and websites (ensembl, HGMD, ClinVar). Only cases with AV in both alleles, either in homozygous or compound heterozygous were included. The included cases were analyzed according to ethnicity, exon, domain, aminoacid (aa) conservation, age at diagnosis, sex assignment, gender reassignment, external genitalia virilization and functional studies. External genitalia virilization was scored using Sinnecker scale. Conservation analysis was carried out using the CONSURF platform. For categorical variables, we used X2 test and Cramer's V. Continuous variables were analyzed by t test or ANOVA. Concordance was estimated by Kappa. Results We identified 434 cases of 5ARD2 deficiencies from 44 countries. Most came from Turkey (23%), China (17%), Italy (9%), and Brazil (7%). Sixty-nine percent were assigned as female. There were 70% of homozygous allelic variants and 30% compound heterozygous. Most were missense variants (76%). However, small indels (11%), splicing (5%) and large deletions (4%) were all reported. They were distributed along with all exons with exon 1 (33%) and exon 4 (25%) predominance. Allelic variants in the exon 4 (NADPH-binding domain) resulted in lower virilization (p<0.0001). The codons 55, 65, 196, 235 and 246 are hotspots making up 25% of all allelic variants. Most of them (76%) were located at conserved aa. However, allelic variants at non-conserved aa were more frequently indels (28% vs 6%; p<0.01). The overall rate of gender change from female to male ranged from 16% to 70%. The lowest rate of gender change from female to male occurred in Turkey and the highest in Brazil. External genitalia virilization was similar between those who changed and those who kept their assigned gender. The gender change rate was significantly different across the countries (V=0.44; p<0.001) even with similar virilization scores. Conclusion 5ARD2 deficiency has a worldwide distribution. Allelic variants at the NADPH-ligand region cause lower virilization. Genitalia virilization influenced sex assignment but not gender change which was influenced by cultural aspects across the countries. Molecular diagnosis influenced on sex assignment, favoring male sex assignment in newborns with 5α-reductase type 2 deficiency.
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Affiliation(s)
- Rafael Loch Batista
- Unidade de Endocrinologia do Desenvolvimento, Laboratório de Hormônios e Genética Molecular/LIM42, Hospital das Clínicas, Disciplina de Endocrinologia, do Departamento de Clínica Médica, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Berenice Bilharinho Mendonca
- Unidade de Endocrinologia do Desenvolvimento, Laboratório de Hormônios e Genética Molecular/LIM42, Hospital das Clínicas, Disciplina de Endocrinologia, do Departamento de Clínica Médica, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
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Gui B, Song Y, Su Z, Luo FH, Chen L, Wang X, Chen R, Yang Y, Wang J, Zhao X, Fan L, Liu X, Wang Y, Chen S, Gong C. New insights into 5α-reductase type 2 deficiency based on a multi-centre study: regional distribution and genotype-phenotype profiling of SRD5A2 in 190 Chinese patients. J Med Genet 2019; 56:685-692. [PMID: 31186340 DOI: 10.1136/jmedgenet-2018-105915] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 05/06/2019] [Accepted: 05/07/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND The 5α-reductase type 2 (5α-RD2) deficiency caused by mutations in the steroid 5α-reductase 2 (SRD5A2) gene results in variable degrees of undervirilisation in patients with 46,XY disorders of sex development. This study aims to profile the regional distribution and phenotype-genotype characteristics of SRD5A2 in a large Chinese 5α-RD2 deficiency cohort through multi-centre analysis. METHODS 190 subjects diagnosed with 5α-RD2 deficiency were consecutively enrolled from eight medical centres in China. Their clinical manifestations and genetic variants were analysed. RESULTS Hypospadias (isolated or combined with microphallus and/or cryptorchidism) was fairly common in the enrolled subjects (66.32%). 42 variants, including 13 novel variants, were identified in SRD5A2. Homozygous and compound heterozygous mutations presented in 38.42% and 61.58% of subjects, respectively, and predominated in exons 1, 4 and 5. The most prevalent variant was c.680G > A (52.37%), followed by c.16C > T, (10.79%), c.607G > A, (9.21%) and c.737G > A, (8.95%). However, their distributions were different: c.680G > A was more common in South China than in North China (62.62% vs 39.16%, p < 0.001), whereas the regional prevalence of c.16C > T was reversed (6.07% vs 16.87%, p = 0.001). Furthermore, c.680G > A prevailed in cases with normal meatus (68.75%) or distal hypospadias (66.28%), compared with those with proximal hypospadias (35.54%, p < 0.001). However, cases with proximal hypospadias showed a higher frequency of c.16C > T (20.48%) than those with normal meatus (3.13%) or distal hypospadias (3.49%, p < 0.001). CONCLUSIONS This study profiled variable phenotypic presentation and wide mutational spectrum of SRD5A2, revealing its distinctive regional distribution in Chinese patients and further shaping the founder effect and genotype-phenotype correlation of SRD5A2.
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Affiliation(s)
- Baoheng Gui
- Department of Genetics and Metabolism, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Yanning Song
- Center of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, The Capital Medical University, Beijing, China
| | - Zhe Su
- Department of Endocrinology and Metabolism, Shenzhen Children's Hospital, Shenzhen, China
| | - Fei-Hong Luo
- Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Shanghai Jiao Tong Univ, Shanghai, China
| | - Linqi Chen
- Department of Endocrinology, Metabolism, and Genetic Diseases, Children's Hospital of Soochow University, Suzhou, China
| | - Xiumin Wang
- Department of Endocrinology and Metabolism, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Ruimin Chen
- Department of Endocrinology, Fuzhou Children's Hospital of Fujian, Fujian Medical University Teaching Hospital, Fuzhou, China
| | - Yu Yang
- Department of Endocrine Genetics and Metabolism, Children's Hospital of Jiangxi Province, Nanchang, China
| | - Jin Wang
- Department of Genetics and Metabolism, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Xiu Zhao
- Department of Endocrinology, Metabolism, and Genetic Diseases, Shenzhen Children's Hospital, Shenzhen, China
| | - Lijun Fan
- Center of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, The Capital Medical University, Beijing, China
| | - Xia Liu
- Department of Endocrinology and Metabolism, Shenzhen Children's Hospital, Shenzhen, China
| | - Yi Wang
- Center of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, The Capital Medical University, Beijing, China
| | - Shaoke Chen
- Department of Pediatrics Endocrinology, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Chunxiu Gong
- Center of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, The Capital Medical University, Beijing, China .,Beijing Key Laboratory for Genetics of Birth Defects, Beijing Children's Hospital, The Capital Medical University, Beijing, China
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Shabir I, Khurana ML, Joseph AA, Eunice M, Mehta M, Ammini AC. Phenotype, genotype and gender identity in a large cohort of patients from India with 5α-reductase 2 deficiency. Andrology 2015; 3:1132-9. [PMID: 26453174 DOI: 10.1111/andr.12108] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 07/27/2015] [Accepted: 08/19/2015] [Indexed: 11/30/2022]
Abstract
Deficiency of the 5α-reductase 2 enzyme impairs the conversion of testosterone to dihydrotestosterone (DHT) and differentiation of external genitalia, seminal vesicles and prostate in males. The present study describes the phenotype, genotype and gender identity in a large cohort of patients with 5αRD2. All patients underwent detailed clinical evaluation, hormonal profile, karyotyping and molecular analysis of the SRD5A2 gene. The molecular analysis of the SRD5A2 gene showed the presence of mutant alleles in 24 patients. We found 6 novel mutations IVS(1-2) T>C, p.A52T, 188-189insTA, 904-905ins A, p.A12T and p.E57X in our patients. All patients had ambiguous genitalia and the degrees of under-virilization ranged from penoscrotal hypospadias and microphallus to clitoromegaly. The position of gonads was variable in patients with same mutation. All the patients with mutations in the SRD5A2 gene had male gender identity. Those reared as female had gender dysphoria and underwent gender reassignment. Though a specific genotype-phenotype correlation could not be established in our patient but confirming the diagnosis of 5αRD2 with assessment of the SRD5A2 gene may help in appropriate gender assignment.
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Affiliation(s)
- I Shabir
- Department of Endocrinology & Metabolism, All India Institute of Medical Sciences, New Delhi, India
| | - M L Khurana
- Department of Endocrinology & Metabolism, All India Institute of Medical Sciences, New Delhi, India
| | - A A Joseph
- Department of Psychiatry, All India Institute of Medical Sciences, New Delhi, India
| | - M Eunice
- Department of Endocrinology & Metabolism, All India Institute of Medical Sciences, New Delhi, India
| | - M Mehta
- Department of Psychiatry, All India Institute of Medical Sciences, New Delhi, India
| | - A C Ammini
- Department of Endocrinology & Metabolism, All India Institute of Medical Sciences, New Delhi, India
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