Evaluation of exon-1 HOX-B7 mutations in Turkish reflux nephropathy patients
We examined a possible influence of HOX gene mutations, which encode factors controlling anterior-posterior development, on vesicoureteral reflux (VUR). For this purpose, we evaluated the HOX-B7 gene as a promoter of the RET gene. From May 2014-June 2015, 33 pediatric patients diagnosed as having VUR at a university urology clinic were enrolled in the study. Patients with other urological malformations were excluded. The mean age was 69 ± 37 months. We found single genetic polymorphisms in 21 patients on HOX-B7 (exons 1 and 2), and 17 patients had polymorphisms only on exon 1. This variant is in a non-encoding area on the gene locus. Nevertheless, the results showed that these variants could be involved in VUR pathogenesis. Exon 1 mutation was found in six patients who had moderate VUR (grade III) and in seven patients who had severe VUR (grades IV and V). Eight patients with exon 1 variants had renal scarring due to reflux, and seven had homozygote mutations. When we examined the correlation between the duration of VUR and renal scarring, the duration of renal scar development in patients with exon 1 variant clustered at 15 months, but there was no significant difference between groups (P = 0.15), and there was no association between exon 1 variations and renal scarring (P = 0.86). The results showed that these variants could be an important gene for VUR pathogenesis. We concluded that a HOX-B7 variant of exon 1 was associated with moderate to severe VUR. Our study support the conclusion that HOX-B7 is an important gene for VUR development, but there was no significant association with renal damage.