title: Molecular analysis of the CYP21A2 gene in Chinese patients with steroid 21-hydroxylase deficiency.
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.
  
  
  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.
authors: 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.
authors: Dingyuan
authors: D
authors: Ma
authors: 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.
authors: Yulin
authors: Y
authors: Chen
authors: 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.
authors: Yun
authors: Y
authors: Sun
authors: 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.
authors: Bing
authors: B
authors: Yang
authors: 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.
authors: Jian
authors: J
authors: Cheng
authors: 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.
authors: Meilian
authors: M
authors: Huang
authors: 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.
authors: Jin
authors: J
authors: Zhang
authors: 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.
authors: Jingjing
authors: J
authors: Zhang
authors: 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.
authors: Ping
authors: P
authors: Hu
authors: 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.
authors: Ying
authors: Y
authors: Lin
authors: 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. Electronic address: jiangzhang784@163.com.
authors: Tao
authors: T
authors: Jiang
authors: 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. Electronic address: njxzf@126.com.
authors: Zhengfeng
authors: Z
authors: Xu
mesh_terms: D000312:Adrenal Hyperplasia, Congenital / Q000201:enzymology* / Q000235:genetics*; D000483:Alleles; D044466:Asian People / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002681:China; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D015321:Gene Rearrangement / Q000235:genetics; D020022:Genetic Predisposition to Disease; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D007223:Infant; D008297:Male; D010641:Phenotype; D013255:Steroid 21-Hydroxylase / Q000235:genetics*; D055815:Young Adult
chemical_list: C531510:CYP21A2 protein, human; D013255:Steroid 21-Hydroxylase
keywords: 21-Hydroxylase deficiency; CYP21A2; Congenital adrenal hyperplasia; Mutation