A Novel Mutation Pattern of Kidney Anion Exchanger 1 Gene in Patients With Distal Renal Tubular Acidosis in Iran

Mutations of the anion exchanger 1 (AE1) gene encoding the kidney anion exchanger 1 can result in autosomal dominant or autosomal recessive form of distal renal tubular acidosis (DRTA). This study aimed to report deletion mutations of the AE1 and its impact on Iranian children with DRTA. Twelve children with DRTA referred to Ali Asghar Children Hospital were investigated for all AE1 gene exons through polymerase chain reaction amplification, DNA sequencing, and bioinformatics analysis. Eleven of 12 patients (91.7%) showed an alteration in AE1 gene with a real hot spot in its exons 11 or 15. Homozygote and heterozygote deletions were confirmed in exon 15 in 5 (41.7%) and 3 (25.0%), respectively. Two patients (16.7%) showed homozygote deletions in exon 11 of AE1 gene, and 1 patient (8.3%) showed point mutation in exon 11. The 3-dimensional structures of the native and these mutant kidney AE1 proteins were determined by the multitemplate method using the Phyre and Hidden Markov Model algorithms. Parent's consanguinity of these patients reveals that cousins are at a high risk for DRTA. This study is considered as a pilot study showing the importance of AE1 mutations in Iranian children with DRTA and further studies is recommended in this geographic region of the world. These models suggest that alteration in the structures leads to alteration in function and change in the current role of AE1.