CYP21A2 Gene Analysis in Southern Iranian CAH Patients and a Brief Review of the  Mutation Spectrum

Danial  Zangene; Hossein  Moravej; Homa  Ilkhanipoor; Anis  Amirhakimi; Zhila  Afshar; Mona  Entezam

doi:10.18502/ajmb.v16i2.14864

Danial Zangene Department of Medical Genetics, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
Hossein Moravej Neonatal Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Homa Ilkhanipoor Department of Pediatric Endocrinology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
Anis Amirhakimi Department of Pediatric Endocrinology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
Zhila Afshar Department of Pediatric Endocrinology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
Mona Entezam Department of Medical Genetics, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran

DOI: https://doi.org/10.18502/ajmb.v16i2.14864

Keywords: Adrenal hyperplasia, Congenital, Genotyping techniques, Mutation

Abstract

Background: CYP21A2 gene mutations are responsible for more than 95% of Congenital Adrenal Hyperplasia (CAH) disorders with autosomal recessive inheritance. Most of these pathogenic mutations originate from the CYP21A1P, a neighboring pseudogene with 98% homology, due to unequal crossing over or gene conversion events. Mutation identification of the gene could be beneficial for accurate diagnosis and outcome prediction.

Methods: Twelve unrelated patients with CAH diagnosis were recruited for genetic counseling. To ensure distinct amplification of the CYP21A2 gene rather than its pseudogene, the complete sequence of the gene was amplified through two overlapping fragments by specific primers. The entire sequences were screened by direct Sanger sequencing using new sequencing primers.

Results: Only two pathogenic point mutations were identified. The c.293-13C>G, also known as In2G, and the c.955C>T mutations were found in 37.5 and 33.3% of alleles, respectively. One patient showed homozygous gene deletion. We also reviewed recent reports on CYP21A2 gene mutations in Iran.

Conclusion: Evaluating the ethnicity-specific gene mutation data is significant for populations with diverse ethnic groups including the Iranian population. Although several common mutations have been reported as causative mutations among CAH patients, identifying only two common point mutations in Fars province would help prioritize exon sequencing and reduce the cost and time of genotyping.