Importance of early audiologic assessment in distal renal tubular acidosis

Anand P Swayamprakasam¹, Elizabeth Stover¹, Elizabeth Norgett¹, Katherine G Blake-Palmer¹, Michael J Cunningham², Fiona E Karet^1
1Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, UK; ²Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, MA, USA

Abstract: Autosomal recessive distal renal tubular acidosis is usually a severe disease of childhood, often presenting as failure to thrive in infancy. It is often, but not always, accompanied by sensorineural hearing loss, the clinical severity and age of onset of which may be different from the other clinical features. Mutations in either ATP6V1B1 or ATP6V0A4 are the chief causes of primary distal renal tubular acidosis with or without hearing loss, although the loss is often milder in the latter. We describe a kindred with compound heterozygous alterations in ATP6V0A4, where hearing loss was formally diagnosed late in both siblings such that they missed early opportunities for hearing support. This kindred highlights the importance of routine audiologic assessments of all children with distal renal tubular acidosis, irrespective either of age at diagnosis or of which gene is mutated. In addition, when diagnostic genetic testing is undertaken, both genes should be screened irrespective of current hearing status. A strategy for this is outlined.

Keywords: sensorineural hearing loss, renal tubular acidosis, recessive, genetics, mutation