INTRODUCTION.
Renal tubular acidosis (RTA) is a medical condition that involves an accumulation of acid in the body due to a failure of the kidneys to appropriately acidify the urine. In renal physiology, when blood is filtered by the kidney, the filtrate passes through the tubules of the nephron, allowing for exchange of salts, acid equivalents, and other solutes before it drains into the bladder as urine. The metabolic acidosis that results from RTA may be caused either by insufficient secretion of hydrogen ions (which are acidic) into the latter portions of the nephron (the distal tubule) or by failure to reabsorb sufficient bicarbonate ions (which are alkaline) from the filtrate in the early portion of the nephron (the proximal tubule).
There is evidence that distal renal tubular acidosis with progressive sensorineural hearing loss (DRTA2) is caused by homozygous or compound heterozygous mutation in the (ATP6B1) gene on chromosome 2p13.3 and genomic coordinates 2:70,935,900-70,965,431. The screenshot the ATP6B1 gene 29,532 bp (base pairs) of DNA sequence length is shown BELOW. Nine (9) other genes besides ATP6B1 in the 2p13.3 cytogenetic location are listed BENEATH.
| Coordinate | Symbol | Genomic Name. |
| 2:70,777,310 | FIGLA | Folliculogenesis specific bHLH transcription factor |
| 2:70,808,643 | CLEC4F | C-type lectin domain family 4, member F |
| 2:70,824,130 | CD207 | CD207 antigen |
| 2:70,900,576 | VAX2 | Ventral anterior homeobox 2 |
| 2:70,935,900 | ATP6V1B1 | ATPase, H+ transporting, V1 subunit B1 |
| 2:70,978,445 | ANKRD53 | Ankyrin repeat domain-containing protein 53 |
| 2:70,985,942 | TEX261 | Testis-expressed gene 261 |
| 2:71,068,296 | NAGK | N-acetylglucosamine kinase |
| 2:71,109,687 | MCEE | Methylmalonyl-CoA epimerase |
| 2:71,130,634 | MPHOSPH10 | M-phase phosphoprotein 10 |
