Correspondence
Hearing Loss
N Engl J Med 1994; 330:714-715March 10, 1994
- Article
To the Editor:
In his excellent, comprehensive review of hearing loss (Oct. 7 issue),1 Dr. Nadol referred specifically to genetic-linkage analyses in Usher's syndrome and Waardenburg's syndrome, but made no mention of the precise genetic basis of Alport's syndrome (hereditary nephritis and sensorineural hearing loss). There is strong genetic linkage of this syndrome to markers near Xq22,2 and the gene responsible at this locus is known to be COL4A5 in at least 50 percent of affected families3,4. More than 50 causative mutations have now been described4,5. In a minority of cases, perhaps 20 percent, transmission is autosomal.
Knowledge of the availability of genetic diagnosis is important because of its application to genetic counseling and family planning as well as to the diagnosis of individual cases within a kindred known to be affected. Specific mutation analysis is practicable in several kindreds with hearing loss and nephritis as well as in one with familial hereditary nephritis and tardive hearing loss. A strong presumptive diagnosis can be made with the use of linkage methods in other families.
5 ReferencesMartin C. Gregory, B.M., B.Ch., D.Phil.
Curtis L. Atkins, Ph.D.
David F. Barker, Ph.D.
University of Utah Health Sciences Center, Salt Lake City, UT 841121
Nadol JB Jr . Hearing loss. N Engl J Med 1993;329:1092-1102
Full Text | Web of Science | Medline2
Barker DF ,Fain PR ,Goldgar DE , et al. High-density genetic and physical mapping of DNA markers near the X-linked Alport syndrome locus: definition and use of flanking polymorphic markers. Hum Genet 1991;88:189-194
CrossRef | Web of Science | Medline3
Hostikka SL ,Eddy RL ,Byers MG ,Hoyhtya M ,Shows TB ,Tryggvason K . Identification of a distinct type IV collagen alpha chain with restricted kidney distribution and assignment of its gene to the locus of X chromosome-linked Alport syndrome. Proc Natl Acad Sci U S A 1990;87:1606-1610
CrossRef | Web of Science | Medline4
Barker DF ,Hostikka SL ,Zhou J , et al. Identification of mutations in the COL4A5 collagen gene in Alport syndrome. Science 1990;248:1224-1227
CrossRef | Web of Science | Medline5
Tryggvason K ,Zhou J ,Hostikka SL ,Shows TB . Molecular genetics of Alport syndrome. Kidney Int 1993;43:38-44
CrossRef | Web of Science | Medline
To the Editor:
In his article on hearing loss, Dr. Nadol made almost no mention of occupationally related noise-induced hearing loss, arguably the most common cause of hearing impairment among adults in the United States and perhaps other countries as well. It is estimated that close to 8 million civilian workers in the United States and many more in the military are exposed to potentially damaging levels of noise.1 The loudness and duration of noise exposure are the primary determinants of the prevalence and severity of noise-induced hearing loss among workers.
Occupationally related noise-induced hearing loss is often irreversible, and effective approaches to prevention, ranging from reduction of noise at the source to the use of protective devices (earmuffs and earplugs) to periodic audiometry for workers exposed to noise, are well known.
1 ReferencesBarry S. Levy, M.D.
Tufts University School of Medicine, Boston, MA 02111David H. Wegman, M.D.
University of Massachusetts, Lowell, MA 01854To the Editor:
In his article on hearing loss, Dr. Nadol did not include another drug that may cause ototoxicity with relative frequency: vancomycin. Vancomycin-induced ototoxicity is manifested by auditory-nerve damage and hearing loss and is more likely in patients with high plasma concentrations of the drug. Tinnitus and high-tone hearing loss are frequently an antecedent to deafness and must be regarded as an indication to discontinue treatment1. Hearing occasionally improves when the drug is discontinued, but it often continues to deteriorate and the loss may be irreversible2,3. Some factors may increase the likelihood of this adverse reaction: the use of high doses, long periods of treatment, preexisting renal failure, older age, previous episodes of hearing loss, and especially, concomitant intake of other ototoxic drugs4.
4 ReferencesJ. Soto, M.D.
Hospital Santa Cruz, 39120 Liencres, SpainM.J. Alsar, M.D.
Hospital Comarcal, 39770 Laredo, Spain1
Brummett RE ,Fox KE . Vancomycin- and erythromycin-induced hearing loss in humans. Antimicrob Agents Chemother 1989;33:791-796
Web of Science | Medline2
Mellor JA ,Kingdom J ,Cafferkey M ,Keane C . Vancomycin ototoxicity in patients with normal renal function. Br J Audiol 1984;18:179-180
CrossRef | Medline3
Traber PG ,Levine DP . Vancomycin ototoxicity in patient with normal renal function. Ann Intern Med 1981;95:458-460
Web of Science | Medline4
Bailie GR ,Neal D . Vancomycin ototoxicity and nephrotoxicity: a review. Med Toxicol 1988;3:376-386
Author/Editor Response
Dr. Nadol replies:
To the Editor: The purpose of my review article was to demonstrate the breadth of causes that may result in conductive and sensorineural hearing loss and to provide an outline of diagnostic and therapeutic strategies rather than to produce an exhaustive and encyclopedic list of all possible causes of hearing loss. I certainly agree with the analysis by Dr. Gregory and colleagues of the importance of genetic linkage in Alport's syndrome, given its prevalence as a cause article. Although I disagree with Drs. Levy and Wegman that occupationally related noise-induced hearing loss is “the most common cause of hearing impairment among adults in the United States” -- a distinction I would reserve for genetically induced hearing loss -- I certainly agree that it is an extremely important cause of sensorineural loss, particularly because it is preventable.
The list of ototoxic and potentially ototoxic drugs administered alone or in combination is very extensive. I thank Drs. Soto and Alsar for pointing out that vancomycin, like erythromycin, is a nonaminoglycoside antibiotic that may produce sensorineural loss.
Joseph B. Nadol, Jr., M.D.
Massachusetts Eye and Ear Infirmary, Boston, MA 02114
