Distal renal tubular acidosis and its relationship with hearing loss in children: preliminary report.
BACKGROUND
In autosomal recessive distal renal tubular acidosis (DRTA), a substantial fraction of the patients have progressive bilateral sensorineural hearing loss. This coexistence is due to the mutations of a gene expressed both in the kidney and in the cochlea. The aim of this study was to assess the correlation between hearing loss and DRTA.


METHODS
In this study, 51 children diagnosed with renal tubular acidosis were evaluated. Diagnosis of DRTA was based on clinical manifestations and detection of normal anion gap metabolic acidosis, urine pH higher than 5.5, and positive urinary anion gap. Audiometry was performed in children with DRTA and sequencing of the ATP6V1B1 gene was done for those with sensorineural hearing loss.


RESULTS
Twenty-seven patients (52.9%) had DRTA, of whom 51.9% were younger than 1 year old, 55.6% were boys, and 44.4% were girls. Eleven patients (40.7%) had bilateral sensorineural hearing loss, consisting of 5 of 15 boys (33.3%) and 6 of 12 girls (50.0%). There was no correlation between hearing loss and gender. Three patients with hearing loss had mutation in the ATP6V1B1 gene (11.1% of patients with DRTA and 27.3% of patients with DRTA and hearing loss).


CONCLUSIONS
This study indicated that a significant percentage of the children with DRTA had sensorineural hearing loss and mutation in ATP6V1B1 gene. It is recommended to investigate hearing impairment in all children with DRTA.
Sharifian
Mostafa
M
Pediatric Infectious Research Center and Department of Nephrology, Mofid Children Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. mostafasharifian@yahoo.com
Esfandiar
Nasrin
N
Mazaheri
Samira
S
Kariminejad
Ariana
A
Mohkam
Masoumeh
M
Dalirani
Reza
R
Esmaili
Rana
R
Ahmadi
Mitra
M
Hassas-Yeganeh
Mehrnoush
M
D000141:Acidosis, Renal Tubular / Q000150:complications* / Q000175:diagnosis / Q000235:genetics; D000293:Adolescent; D001299:Audiometry; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D003937:Diagnosis, Differential; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000209:etiology* / Q000235:genetics; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007223:Infant; D008297:Male; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics
C509766:ATP6V1B1 protein, human; D025262:Vacuolar Proton-Translocating ATPases