Association of a variant of V281L of 21-hydroxylase gene CYP21A2 with simple virilizing and salt wasting types of CAH in Pakistani population

Madiha Shahbaz; Qaiser Mansoor; Maleeha Akram; Misbah Riaz; Azhar Beg; Shaista Aslam; Gulben Shahid; Mazhar Qayyum; Naseem Afzaal Ahmed; S.S.R. Rizvi; Muhammad Ismail

doi:10.1530/endoabs.32.P44

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Endocrine Abstracts (2013) 32 P44 | DOI: 10.1530/endoabs.32.P44

ECE2013 Poster Presentations Adrenal cortex (64 abstracts)

Association of a variant of V281L of 21-hydroxylase gene CYP21A2 with simple virilizing and salt wasting types of CAH in Pakistani population

Madiha Shahbaz ¹ , Qaiser Mansoor ² , Maleeha Akram ¹ , Misbah Riaz ¹ , Azhar Beg ¹ , Shaista Aslam ³ , Gulben Shahid ⁴ , Mazhar Qayyum ¹ , Afzaal Ahmed Naseem ¹ , S.S.R. Rizvi ^5, & Muhammad Ismail ²

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¹Department of Zoology, PMAS Arid Agriculture University, Rawalpindi, Pakistan; ²Institute of Biomedical and Genetic Engineering (IBGE), Islamabad, Pakistan; ³Department of Zoology, Government College University, Rawalpindi, Pakistan; ⁴Pakistan Institute of Sciences (PIMS), Children Hospital, Islamabad, Pakistan; ⁵Pakistan Science Foundation, Islamabad, Pakistan.

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder caused by deficiency of 21-hydroxylase (CYP21), which inhibits adrenal synthesis of cortisol and aldosterone. The reduced cortisol synthesis leads to increased ACTH secretion, which results in adrenal gland hyperplasia, accumulation of steroid precursors and excessive adrenal androgen production, causing pseudoprecocious puberty. The study aimed at determining variance in two SNPs, I172N and V281L, of CYP21A2 gene in twenty male CAH (13 salt wasting and 7 simple virilizing) patients and 20 age-matched controls. Genomic DNA was extracted and PCR-RFLP analysis was done. The genotypic frequency of wild type for two SNPs in case of controls and patients were 0.9, 1, 0.86, and 0.63% respectively. The heterozygous frequencies were 0.1, 0, 0.14, and 0.16% respectively. The PCR product of CYP21A2 I172N digested by Hind III gave bands of AA genotype comprised of a segment of ~168 bp. The frequency of this genotype was 0.9% in controls and 0.86% in patients. Similarly, the genotypic frequency of other genotype AT, comprising segments of 168, 142, and 26 bp was 0.1% in controls and 0.14% in cases. The genotypes did not differ significantly between the two groups. Hence, the variant I172N of CYP21A2 was not associated with CAH. For V281L of CYP21A2 gene, PCR amplification yielded a segment of ~207 bp. BamH1 gave bands of three different genotypes, CC (178 and 29 bp segments) in ten controls and 12 patients, AC (207,178, and 29 bp segments) in no control and three CAH patients and AA (segment of 207 bp) genotypes in no control and four CAH patients. In conclusion, V281L mutation was identified in seven of the total 20 patients studied. The frequency of V281L was 35% in CAH patients. The mutation V281L was found to be associated with both simple virilizing (20%) and salt wasting (15%) types of CAH.