Medicina molecular y genética

Molecular Identification of Intron 2 Splice Mutation and 8bp Deletion in CYP21 Gene for Congenital Adrenal Hyperplasia (CAH) Patients in Kashmir (North India)

Abstract

Mahrukh H Zargar, Arshad A Pandith, Tahir M Malla, Shahnawaz Akber and Faheem Shehjar

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder caused by alteration in CYP21 gene which ultimately leads to 21-hydroxylase deficiency. The present study aimed at evaluation of 2 common mutations viz, Intron 2 Splice (INT2S) mutation and 8 bp deletions in exon 3 of CYP21 gene and to establish their frequencies in Kashmir population (North India). The mutations were tested by Amplification Refractory Mutation System-PCR (ARMS-PCR) in 50 cases of CAH, proven by clinical features and raised 17-hydroxy progesterone (17OHP) levels.

The results revealed that 15(30%) cases had INT2S mutation while as 8 bp deletion was not detected in any patient. In INT2S mutation, 7 cases were homozygous with I2-G genotype and 8 cases were heterozygous. The frequency of AG heterozygotes was found in 5 cases and CG heterozygote genotype was found in 3 cases. CAH patients with ambiguous genitalia were seen to harbor most of the INT2S mutations with I2-G in 3 cases and CG heterozygotes in 2 cases. In non-consanguineous group of patients, 4 homozygous I2-G mutations and 4 were I2- GC heterozygotes were detected in comparison to 3 and 1 in consanguineous patients respectively. Our study confirms that INT2S mutations but not 8 bp deletions exist in CYP21 gene in CAH patients in Kashmir population.