Longitudinal Analysis of Hearing Impairment

ORIGINAL ARTICLE A Dutch Family With Hearing Loss Linked to the DFNA20/26 Locus Longitudinal Analysis of Hearing Impairment

Martijn H. Kemperman, MD; Els M. R. De Leenheer, MD, PhD; Patrick L. M. Huygen, PhD; Erwin van Wijk; Gerard van Duijnhoven; Frans P. M. Cremers, PhD; Hannie Kremer, PhD; Cor W. R. J. Cremers, MD, PhD

Objectives: To perform linkage analysis and to out- at 8 kHz and 1 to 4 kHz, respectively. The 0.25- to 0.5- line hearing loss characteristics in a family exhibiting a kHz thresholds showed more gradual progression by about nonsyndromic, autosomal dominant type of progres- 1.5 to 2 dB/y. From about age 40 years onward, hearing sive sensorineural hearing loss. was residual. Hearing impairment took a more severe course than in a known DFNA20 family. Score recogni- Design: Genetic analysis was performed using micro- tion in DFNA20/26 subjects was better than in DFNA9 satellite markers. Audiometric data were collected and subjects at any pure-tone average (1-4 kHz) threshold. analyzed longitudinally. Sigmoidal dose-response curves Compared with subjects having DFNA2 and DFNA5, enabled us to perform nonlinear regression analysis per speech recognition in those with DFNA20/26 scored bet- frequency and on phoneme recognition scores. Speech ter at threshold levels below 85 dB hearing level, but worse recognition scores were compared with those of DFNA2, at levels above 90 dB. Compared with presbyacusis sub- DFNA5, DFNA9, and presbyacusis subjects. jects, those with DFNA20/26 scored better in speech recognition at levels below 100 dB and worse at levels above Subjects: Affected family members of a Dutch family 100 dB. (W99-060). Conclusions: Autosomal dominant hearing loss is linked Results: We revealed linkage of hearing loss to the to the DFNA20/26 locus in this Dutch family. The criti- DFNA20/26 locus (maximum logarithm of odds score, cal region is reduced from 12 to 9.5 centimorgans. Phe- 3.1 at ␪=0.04) and reduced the critical region from 12 notypically, patients are more severely affected than those to 9.5 centimorgans. Patients younger than 15 years al- of a known DFNA20 family. ready showed gently downsloping audiograms. At ages 15 to 20 and 25 to 40 years, hearing loss was profound Arch Otolaryngol Head Neck Surg. 2004;130:281-288

ENETIC HEARING LOSS IS are due to either autosomal dominant or one of the most fre- mitochondrial mutations.5 In recent years, quent forms of sensori- mapping of deafness loci has become a neural deficits handicap- common research effort. So far, 41 auto- ping people of all ages somal dominant, 33 autosomal recessive, worldwide.G Ten percent of the popula- and 6 X-linked loci associated with non- tion older than 65 years and 50% of those syndromic hearing impairment have been older than 80 years are affected.1 About 1 mapped, and 29 different genes have been child in 1000 is born with prelingual hear- identified.6 ing loss, and in at least half of these cases, Recessive forms of hearing loss gen- 2,3 From the Departments of the cause is inherited. According to Mor- erally involve all frequencies, are mostly Otorhinolaryngology ton,1 approximately 77% of the nonsyn- congenital or prelingual, and range in se- (Drs Kemperman, Leenheer, dromic inherited forms of moderate to pro- verity from severe to profound.7 For domi- Huygen, Kremer, and C. found hearing loss in early childhood show nantly inherited hearing loss, there is more Cremers and Mr van Wijk) and an autosomal recessive pattern of inher- variation, and clearly different types can Human Genetics (Drs itance (DFNB) in contrast to 22% with an be distinguished on the basis of the fre- Kemperman and F. Cremers autosomal dominant (DFNA) type. The quencies involved, severity, age of onset, and Mr Duijnhoven), 7-10 University Medical Center percentage of X-linked hearing loss (DFN) and speech recognition scores. De- Nijmegen, Nijmegen, the is 1%, whereas hearing loss with a mito- spite intrafamilial and interfamilial varia- Netherlands. The authors have chondrial pattern of inheritance occurs tion in hearing loss caused by specific loci no relevant financial interest in sporadically.1,4 It seems that most of the and/or genes, it is possible to differenti- this article. hereditary types of postlingual hearing loss ate between a number of these loci based

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II II:1 II:2 II:3 II:4

III III:1 III:2 III:6 III:7 III:8 III:9 III:11 III:12 III:14 III:15 III:16 III:17 D17S1806 8 1 D17S1830 1 2 D17S784 7 2 D17S761 2 3 D17S668 1 3 D17S928 4 3 D17S623 3 3

IV IV:1 IV:2 IV:5 IV:7 IV:8 IV:9 IV:11 IV:12 IV:15 IV:16 IV:18 IV:19 IV:22 IV:23 IV:27 IV:28 IV:29 D17S1806 8 1 9 3 4 6 4 5 4 4 4 6 2 5 4 5 4 2 4 5 8 6 10 6 2 7 9 8 9 2 9 2 D17S1830 3 2 1 6 4 6 2 3 4 2 4 6 6 3 2 5 2 3 6 5 4 6 4 6 3 6 4 4 4 4 4 4 D17S784 4 2 7 5 4 3 3 1 4 3 4 3 2 2 3 2 3 4 4 4 4 3 4 3 4 2 4 4 4 4 4 4 D17S761 3 3 3 3 3 2 3 2 3 2 3 2 2 2 2 2 2 2 1 3 2 2 3 2 2 2 3 2 3 3 3 3 D17S668 3 2 3 1 3 2 3 4 2 2 2 2 3 2 2 4 2 3 3 2 2 2 3 2 4 3 3 2 3 3 3 3 D17S928 2 3 3 2 4 1 4 4 4 3 4 1 3 6 3 4 3 5 4 3 7 1 2 1 8 4 2 7 2 2 2 2 D17S623 3 3 3 3 3 2 3 3 3 3 3 2 3 4 3 3 3 4 3 3 1 2 3 2 3 3 3 3 3 2 3 2

V V:2 V:5 V:6 V:7 V:8 V:10 V:15 V:16 V:21 V:22 V:27 D17S1806 4 4 4 5 6 5 6 4 4 5 6 4 2 6 2 4 6 4 8 4 2 10 D17S1830 4 2 4 3 6 3 6 2 4 3 6 2 6 6 6 4 6 6 4 6 3 4 D17S784 4 3 4 1 3 1 3 3 4 1 3 3 2 3 2 4 3 4 4 4 4 4 D17S761 3 3 2 2 2 2 2 3 3 2 3 3 2 2 2 3 2 1 2 1 2 3 D17S668 3 4 2 4 2 4 2 3 3 4 3 3 3 2 3 2 2 3 2 3 4 3 D17S928 4 4 1 4 1 4 1 4 4 4 4 4 3 1 6 4 1 4 7 4 8 2 D17S623 3 3 2 3 2 3 2 3 3 3 3 5 3 2 4 3 2 3 1 3 3 3

VI VI:4 D17S1806 8 4 D17S1830 3 4 D17S784 1 4 D17S761 2 2 D17S668 3 2 D17S928 2 1 D17S623 3 2

Figure 1. Pedigree of family W99-060 and genotypic data for 17q25 markers listed in centromere-to-telomere order. The most likely haplotypes are shown. A black bar indicates the haplotype that is associated with the affected status. Solid lines indicate an unknown phase. The order of the markers D17S1806, D17S784, D17S668, and D17S928 follows that of the Marshfield genetic map (available at: http://research.marshfieldclinic.org/genetics) and the Decode high-resolution recombination map.15 The additional markers were positioned as given in the most recent freeze (April 2003) of the Human Genome Working Draft (http://genome .ucsc.edu) and the Celera database. A square indicates a male family member; circle, female member; open symbol, unaffected person; solid symbol, affected person; slash through a symbol, deceased person; double slash through connecting lines, separated relationship; question mark, affected by history.

on clinical characteristics.7,9,11,12 Phenotypic and geno- samples were collected from 11 presumably affected and 22 un- typic characterization of families is important for in- affected persons for linkage analysis. Special attention was paid sight into intralocus and interlocus variation in hearing to the presence of syndromic features possibly accompanying loss. hearing loss. Herein, we describe a Dutch family (W99-060) with LINKAGE ANALYSIS progressive sensorineural autosomal dominant hearing impairment linked to the DFNA20/26 locus. Statistical Genomic DNA was extracted from peripheral blood lympho- analysis was performed on pure-tone audiometry data and cytes according to established procedures.16 Analysis of poly- on speech-recognition scores. The results were com- morphic markers involved amplification by polymerase chain pared with those previously reported for 4 affected fam- reaction. Each reaction contained 100 ng of genomic DNA and ily members of a known DFNA20 family13; speech rec- 30 ng of each primer in 15 µL of Supertaq buffer (50mM po- ognition scores were compared with those found in tassium chloride, 1.5mM magnesium chloride, 10mM Tris- subjects with DFNA2,8 DFNA5,9 DFNA9,8 and presbya- hydrochloride [pH 9.0], 0.1% Triton X-100, and 0.01% [wt/ cusis.14 vol] gelatin) in the presence of phosphorus 32–dCTP with 0.06 U of Supertaq (HT Biotechnology Ltd, Cambridge, England). METHODS Amplification was achieved by 35 cycles of 1 minute at 94°C, 2 minutes at 55°C, and 3 minutes at 72°C with microsatellite In 1999, we began our investigations of hearing loss in a large markers. The radiolabeled polymerase chain reaction prod- Dutch family (W99-060) spanning 6 generations (Figure 1)15 ucts were mixed with 15 µL of sample buffer (95% for- with the approval of the institutional review board. Fourteen mamide, 20mM EDTA, and 0.05% bromophenol blue) and family members had a history of progressive hearing impair- heated to 95°C for 3 minutes; 4 µL of this mixture was sepa- ment that first manifested in adolescence. After having ob- rated on a 6.6% denaturing polyacrylamide gel. tained written and informed consent, we obtained pure-tone Subsequently, the gel was dried and exposed overnight to and speech audiograms from 22 individuals using standard pro- Kodak X-OMAT film (Eastman Kodak Co, Rochester, NY) to cedures and, in some cases, a portable audiometer. Previously visualize the separated allelic bands. Two-point logarithm of obtained audiograms were retrieved for 13 individuals. Blood odds (lod) scores were calculated using the MLINK subrou-

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©2004 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/24/2021 Two-Point Logarithm of Odds Scores Between the Hearing Loss and Polymorphic Markers of the DFNA20/26 Region

␪

Marker 0.00 0.01 0.05 0.1 0.2 0.3 0.4 Zmax (␪) D17S1806 −12.03 −6.06 −4.65 −3.86 −2.04 −1.04 −0.42 D17S1830 −4.08 0.54 1.71 1.95 1.65 0.97 0.29 D17S784 −9.34 −3.62 −1.64 −0.91 −0.48 −0.39 −0.25 D17S761 −1.61 0.38 0.89 0.94 0.70 0.38 0.09 D17S668 2.20 2.06 1.89 1.65 1.12 0.54 0.04 D17S928 1.89 2.87 3.07 2.78 1.84 0.79 −0.03 3.10 (0.04) D17S623 0.79 2.07 2.36 2.18 1.52 0.74 0.00

Abbreviations: ␪, recombination fraction; Zmax, maximum logarithm of odds score.

10 tine of the computer program LINKAGE (version 5.1) on the RESULTS basis of autosomal dominant inheritance. For the calculation, the relative prevalence of the disease allele was assumed to be 0.0001; penetrance, 95%. A relative prevalence of 0.001 was The hearing loss trait in the family (Figure 1) exhibits assumed for phenocopies. The cutoff age for unaffected family an autosomal dominant pattern of inheritance. The case members was 20 years. histories and physical examinations excluded syndromic involvement. Most of the patients dated their first AUDIOMETRIC ANALYSIS symptoms of hearing loss to the first 2 decades of life. Given the normal speech and language development and Audiometric configuration and threshold asymmetry were evalu- the substantial progression of hearing loss, especially in ated according to the criteria and classification established by the European Work Group on Genetics of Hearing Impair- the second decade, the hearing loss is expected to be ment.17 Serial audiometry was available for 8 patients and suit- mainly postlingual in origin. able for longitudinal analysis for 5 of them (VI:4, IV:19, V:6, V:15, and V:21). Nonlinear longitudinal regression analysis (air- LINKAGE ANALYSIS RESULTS conduction threshold on age) was performed using a commer- cial program (Prism 3.02; GraphPad, San Diego, Calif). The bone Because of the apparent similarity of the present type of conduction threshold was measured to exclude conductive hear- hearing loss to that associated with DFNA5, this locus ing loss. One-way analysis of variance was used to detect sig- was tested first with polymorphic markers (eg, D7S673, nificant differences between any groups or subgroups of pa- D7S2444, and D7S2493). The locus was excluded by lod tients. Pooling was only performed where it was permitted scores lower than −2 (data not shown). Subsequently, a according to the results of such tests. All these data enabled us to construct age-related typical audiograms (ARTA). genome scan was initiated, and after exclusion of about Speech-recognition scores were measured using (phoneti- one third of the genome, linkage was detected with marker cally balanced) standard consonant-vocal-consonant (CVC) syl- D17S928 (17q25) at a maximum 2-point lod score of 3.1 lables (Dutch CVC word lists). The phoneme score was ana- at ␪=0.04. This marker flanks the DFNA20 interval on lyzed in relation to age and pure-tone average (PTA) of the the telomeric side.19 Additional markers derived from this thresholds at 1, 2, and 4 kHz (PTA1-4 kHz). Nonlinear regres- region were tested, and 2-point lod scores were calcu- sion analysis was performed using a sigmoid response curve lated (Table). 8 with variable slope. Details can be found in a previous report. The most likely haplotypes were constructed to de- Analysis of variance and the t test (with the Welch cor- termine the borders of the critical region (Figure 1). This rection if the Bartlett test demonstrated significantly unequal revealed that individual IV:2 had only the allele for marker variances) were used to compare the results with those previously obtained in (1) a group of patients with presbyacusis14; D17S668 as seen with the affected haplotype. A geno- (2) a group of DFNA9 subjects8; and (3) a group of DFNA5 typing error was excluded by analyzing DNA from 2 in- subjects.9 dependent samples. Since both parents had died, we were unable to determine whether allele 2 was derived from VESTIBULOOCULAR EXAMINATION AND the affected mother. Therefore, we decided to deter- IMAGING TECHNIQUES mine the critical region primarily on the basis of the re- maining part of the pedigree. Seven family members (IV:7, IV:11, IV:22, V:5, V:6, V:15, and On the centromeric side, the critical region is flanked VI:4) underwent vestibular and ocular motor tests. These in- by D17S784 as can be deduced from a recombination cluded evaluation of vestibuloocular responses using electro- event seen in the affected individual V:5. Individual V:10 nystagmography with computer analysis and saccadic, smooth pursuit, and optokinetic nystagmus responses. Vestibular stimu- (33 years old at examination) also displays a recombi- lation comprised rotatory and caloric tests. Details and nor- nation event suggesting that marker D17S784 is the proximal values have been previously described.18 A computed to- mal flanking marker. However, for this individual, non- mographic scan of the petrosal bones of subject IV:22 was penetrance cannot be excluded. The given location of the performed (Somatom Plus 4; Siemens, Forchheim, Germany). marker D17S1830 relative to D17S784 is based on physi-

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©2004 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/24/2021 ries the mutation, the critical region based on the given cen marker order would be delimited to the interval between D17S761 and D17S928. However, because of the D17S1350 extent of genetic heterogeneity and environmental causes of hearing loss, the results for individual IV:2 must be regarded with caution. Unfortunately, patient IV:1 re- 20.4

USH1G fused to participate in this study. Assuming that 1 gene is involved in the hearing loss in the 4 families known

25.7 21 to be linked to 17q25,5,19,21 our data reduce the critical 19 D17S1806 region from 12 centimorgans (cM), between D17S1806 and D17S668, to 9.5 cM between D17S784 and D17S668. 2.5 In the recently published high-resolution recombina- 15 D17S1830 tion map of Decode, this distance measures only 6.1 cM. 0.0 D17S784 AUDIOMETRIC ANALYSIS

The available audiograms of 10 affected cases are shown DFNA20 in Figure 3. Before they were 15 years old, the patients had already shown gently downsloping audiograms. By W99-060 18 ages 15 to 20 and 25 to 40 years, hearing loss had be- 9.6 5.5 come severe to profound at 8 kHz and 1 to 4 kHz, respectively. The thresholds at 0.25 to 0.5 kHz showed more gradual progression at an average increase of about 1.5 to 2 dB/y. There was residual hearing (ie, mainly at the lower frequencies) from about age 40 years onward. Figure 4 shows the age-related typical audiograms of the present family and, for the sake of comparison, of a D17S668 13 0.0 0.0 known DFNA20 family. D17S928 The plots in Figure 5 combine the longitudinal D17S623 analyses in the suitable cases with the (cross-sectional) data in the other cases. Cross-sectional data reported by Elfenbein et al13 are included for the purpose of com-

qter parison. The bottom panel shows the phoneme recognition score in relation to age. The threshold data showed much higher progression at the high frequencies than at Figure 2. Representation of the critical regions of family W99-060 of the present study, a known DFNA20 family,19 and the USH1G locus.20 Order and the lower frequencies. The maximum rate of progres- distances in centimorgans of the underlined markers are according to the sion culminated within the age range of 10 to 35 years Marshfield genetic map (available at: http://research.marshfieldclinic.org and varied in individual cases between about 3 and 8 dB/y. /genetics) (left) and/or the Decode genetic map (right).15 Additional markers Onset ages were in the range of 5 to 25 years, showing are located according to their positions in the Human Genome Working Draft (April 2003 freeze; available at: http://genome.ucsc.edu) and the Celera data- an apparent decrease at increasing frequencies in some base. cases. At age 15 to 35 years, 50% of the final degree of deterioration had developed, and by age 30 to 50 years, 90% of the final degree of deterioration had developed. cal maps15,19,20 (Figure 1 and Figure 2) and might there- Appreciable deterioration of speech recognition (score fore be less reliable than marker orders based on genetic Ͻ90%) began between ages 15 and 40 years and showed maps or radiation hybrid maps. If markers D17S1830 are large intersubject variations (Figure 5, bottom panel). At located distally from D17S784, the former marker would age 20 to 45 years, recognition scores deteriorated maxi- be the proximal flanking marker. mally (range, 5%-20% per year). With few exceptions, There is no recombination seen for the most telo- speech recognition became problematic (maximum pho- meric marker, D17S623, and thus the linkage interval for neme score Ͻ50%) from about age 25 to 45 years and on- this family is between D17S784 and 17qter. Marker ward. Between ages 30 and 60 years, speech recognition D17S623 is the only marker shown for which the posi- was almost completely lost except in 1 patient. tion in the physical map is not compatible with that shown In relation to the corresponding threshold level (ie, by the Marshfield genetic map in which it is at the same PTA1-4 kHz), the phoneme recognition score was rela- position as D17S1830 and D17S784 (Marshfield map tively good compared with that previously obtained at available at: http://research.marshfieldclinic.org/genetics). our clinic in patients with presbyacusis,14 DFNA2,8 Recombination events seen in the individuals V:5 and V:10 DFNA5,9 and DFNA9.8 The slope at which the pho- indicate that D17S623 is located on the telomeric side neme recognition score decayed with increasing PTA level of D17S784. The definition of the critical region is not appeared to be steeper than in the aforementioned dif- dependent on the position of D17S623. ferent groups of patients (Figure 6).8,9,14 The recogni- Regarding the allele of marker D17S668 in indi- tion score in DFNA20/26 subjects was better than in vidual IV:2 being derived from the haplotype that car- DFNA9 subjects at any PTA. Compared with DFNA2 and

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–10 0 14.99 y 15.62 y 19.25 y 18.34 y 20 23.58 y 19.15 y 40 22.20 y 23.24 y 60 25.40 y 27.14 y 80

100

120

C V:15 R V:15 L D V:5 R V:5 L

–10 0 11.92 y 34.44 y 17.32 y 38.82 y 20 18.23 y 40 19.31 y 21.45 y 60 24.68 y 26.99 y 80 31.58 y 100

120

E V:6 R V:6 L F V:7 R V:7 L

–10 0 32.77 y 42.00 y 34.49 y 20 35.60 y 40 41.21 y

Threshold, dB HL 100

120

G IV:23 R IV:23 L H IV:19 R IV:19 L

–10 0 40.35 y 42.84 y 47.03 y 45.33 y 20 52.21 y 47.75 y 40 50.20 y 52.51 y 60 57.10 y 80

100

120

I IV:11 R IV:11 L J IV:2 R VI:2 L

–10 0 58.43 y 53.6 y 59.60 y 62.28 y 20 59.78 y 40

100

120

0.25 0.5 1 2 4 8 0.25 0.5 1 2 4 8 0.25 0.5 1 2 4 8 0.25 0.5 1 2 4 8 Frequency, kHz Frequency, kHz

Figure 3. Serial audiograms of 10 family members (A-J) shown for the right (R) and left (L) ears separately (air-conduction threshold in decibels hearing level [dB HL]). Note that the panels are ordered (top left to bottom right) by age in years at the last visit. Some of the serial audiograms have been omitted for clarity.

DFNA5 subjects, DFNA20/26 subjects scored better in pared with presbyacusis subjects, those with DFNA20/26 speech recognition at PTAs lower than 85 dB HL (hear- scored better in speech recognition at PTAs lower than ing level), but worse at PTAs higher than 90 dB. Com- 100 dB and worse at PTAs higher than 100 dB.

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©2004 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/24/2021 tween affected and unaffected persons. With increasing W99-060 DFNA20 age, hearing loss increased at all frequencies, ultimately –10 0 manifesting as a “corner audiogram” configuration. 16 The hearing loss of the present Dutch DFNA20/26 fam- 20 10 ily shows some similarities with that of the American fam- 40 24 ily reported by Elfenbein et al,13 but the audiometric data 60 also revealed apparent differences. We demonstrated that 30 20 40 47 hearing loss was profound by age 15 to 20 and 25 to 40 80

Threshold, dB HL years at 8 and 1 to 4 kHz, respectively. Loss at the lower 100 50-60 66 frequencies (ie, 0.25-0.5 kHz) showed more gradual pro- 120 gression at an average increase of about 1.5 to 2 dB/y. Af- 0.25 0.5 1 2 4 8 0.25 0.5 1 2 4 8 fected individuals have only residual hearing from an age Frequency, kHz of about 40 years onward. Thus, hearing impairment in the Dutch DFNA20/26 family has a more severe appearance Figure 4. Age-related typical audiograms of family W99-060, the present than that in the American family (Figure 4). Higher thresh- family, and of a known American DFNA20 family.13 Italics indicate age in old levels were attained at an earlier age at any given fre- years. HL indicates hearing level. quency. Obviously, comparing purely longitudinal data of both families would be more appropriate, but Figure 4 may VESTIBULOOCULAR EXAMINATION give some indication of the difference in severity. AND IMAGING RESULTS The DFNA20/26 patients in the present family showed better maximum speech recognition scores in re- While caloric testing revealed no abnormalities, patient lation to the level of pure-tone hearing impairment at lev- IV:7 exhibited vestibular hyporeflexia and asymmetri- els below 80 to 90 dB HL than was found in patients with cal responses to rotatory tests. Severe vestibular hypo- DFNA2, DFNA5, DFNA9, or presbyacusis. However, ow- reflexia and an enhanced cervicoocular reflex were noted ing to a steeper slope of the trend line pertaining to in family member IV:22. Vestibular testing in 6 other par- DFNA20/26, these patients showed lower scores at lev- ticipants (IV:11, IV:22, V:5, V:6, V:15, and VI:4) re- els above 90 dB than the DFNA2 and DFNA5 patients vealed no abnormalities. The middle and inner ear struc- and scores similar to presbyacusis subjects at about 100 tures of family member IV:22 had a normal appearance dB (Figure 6). Elfenbein et al13 mentioned the proband’s on computed tomographic scans. poor speech recognition scores but did not provide details; they included data on acoustic emissions but no de- COMMENT tailed data on speech recognition scores. We did not evalu- ate otoacoustic emissions. The Dutch family in the present study shows postlingual, A survey of the critical region for candidate genes for nonsyndromic, progressive, sensorineural hearing loss with DFNA20/26 suggested that the P4HB gene, encoding the probably no or very limited vestibular involvement. This beta subunit of prolyl 4-hydroxylase, was the most prom- is the fourth DFNA family found to have hearing loss linked ising. The P4HB protein catalyzes the formation of 4-hy- to chromosome 17q25. The critical region, originally de- droxyproline in collagens and thereby is important for the scribed by Morell et al,19 is located between markers structure and function of collagen. In addition, the pro- D17S1806 and D17S668 and occupies an interval of about tein functions as protein disulfide isomerase and as a cel- 12 cM (Figure 2). Yang and Smith21 described 2 unre- lular thyroid hormone binding protein. However, a disease- lated American families with progressive autosomal domi- causing mutation in this gene could not be demonstrated nant hearing loss with linkage to a region overlapping the in the DFNA2019 family or in the present family. DFNA20 interval.6 The locus for these 2 families was des- The difference in phenotype between the previously ignated DFNA26.6 Flanking markers for the DFNA26 lo- described American DFNA20 family,19 based on data of cus have not been reported so far. Extensive clinical com- only 4 family members,13 and the present family does not parison with these DFNA26 families is prohibited by the exclude the involvement of the same causative gene. Dif- present lack of reported audiometric data. ferent types of mutations might lead to different pheno- The originally reported type of hearing impair- types. However, it can also be hypothesized that different ment associated with DFNA20 showed progressive sen- genes are causing different traits linked to the DFNA20/26 sorineural hearing impairment with a relatively late on- interval. An example is the recent localization of a gene set (age 20 years) that predominantly affected the high for Usher syndrome type 1G (USH1G) to 17q24-q2520 over- frequencies. The pattern of hearing loss was suggested lapping with the DFNA20 interval as it was described by to resemble presbyacusis but having an onset that is 30 Morell et al.19 Since the critical region for USH1G is flanked years earlier than normal.19 Recently, audiometric data by D17S1830 on the telomeric side, this locus does not were reported for 4 affected family members by Elfen- overlap with the critical region determined for the Dutch bein et al,13 who described downsloping sensorineural family (Figures 1 and 2). Therefore, we conclude that the hearing loss first evident at 6 kHz and later at 8 kHz. This distal part of chromosome 17q harbors at least 2 caus- pattern could be demonstrated in some patients in their ative genes for hearing loss. early teenage years but was clearly evident only by age The mouse mutation jackson-shaker (js) associated 24 to 29 years. By the end of the third and fifth decades, with deafness and vestibular impairment is located in the clear differences were found at some frequencies be- region of mouse chromosome 11, homologous to human

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100

1 kHz 2 kHz 120

100

4 kHz 8 kHz 120

100

Air-Conduction Threshold, dB HL20 Air-Conduction Threshold, dB HL Air-Conduction Threshold, dB HL

10 15 20 25 30 35 40 45 50 55 60 65 10 15 20 25 30 35 40 45 50 55 60 65 Age, y

120 Phoneme Recognition

100

40 Correct Response, %

10 15 20 25 30 35 40 45 50 55 60 65 Age, y

Figure 5. Plots combining individual longitudinal data (with connection lines) and separate cross-sectional data from our subjects (open circles) for binaural mean air-conduction threshold and phoneme recognition scores against age. Black triangles and squares indicate cross-sectional and longitudinal data, respectively, from the American family described by Elfenbein et al.13 HL indicates hearing level.

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©2004 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/24/2021 jmegen, the Netherlands (e-mail: M.Kemperman 100 DFNA2 DFNA20/26 @kno.umcn.nl). 90 REFERENCES 80 DFNA5

70 1. Morton NE. Genetic epidemiology of hearing impairment. Ann N Y Acad Sci. 1991; 630:16-31. 60 DFNA9 presby 2. Marazita ML, Ploughman LM, Rawlings B, Remington E, Arnos KS, Nance WE. Genetic epidemiological studies of early-onset deafness in the US school-age

Correct Responses, % population. Am J Med Genet. 1993;46:486-491. 50 3. Martini A, Read A. Genetics and Hearing Impairment. London, England: Whurr Publishers Ltd; 1996. 40 4. Ensink RJH, Huygen PLM, Cremers CWRJ. The clinical spectrum of maternally 40 50 60 70 80 90 100 110 transmitted hearing loss. Adv Otorhinolaryngol. 2002;61:172-183. 5. Kalatzis V, Petit C. The fundamental and medical impacts of recent progress in PTA1-4 kHz, dB HL research on hereditary hearing loss. Hum Mol Genet. 1998;7:1589-1597. 6. Van Camp G, Smith RJH. Hereditary hearing loss homepage. Available at: http: Figure 6. Plot showing relationship between phoneme recognition score \\dnalab-www.uia.ac.be/dnalab/hhh/. Accessed October 2002. (percentage of correct responses) and binaural mean pure-tone average of 7. The genetics of non-syndromic hearing loss. Available at: http:\\linkage.rockefeller.edu/

the thresholds at 1, 2, and 4 kHz (PTA1-4 kHz). The PTA1-4 kHz is shown nshl/. Accessed October 2002. schematically by lines drawn for DFNA2, DFNA5, and DFNA9 families and the 8. Bom SJH, De Leenheer EMR, Lemaire FX, et al. Speech recognition scores re- Dutch DFNA20/26 family. Presbyacusis (presby) is represented by a dotted lated to age and degree of hearing impairment in DFNA2/KCNQ4 and DFNA9/ line. HL indicates hearing level. COCH. Arch Otolaryngol Head Neck Surg. 2001;127:1045-1048. 9. De Leenheer EMR, van Zuijlen DA, Van Laer L, et al. Further delineation of the DFNA5 phenotype: results of speech recognition tests. Ann Otol Rhinol Laryn- gol. 2002;111:639-641. chromosome 17q25.22 Given the vestibular impairment, 10. Lathrop GM, Lalouel JM, Julier C, Ott J. Strategies for multilocus linkage analysis in humans. Proc Natl Acad Sci U S A. 1984;81:3443-3446. it seems more likely that the mutated gene in the js mouse 11. Huygen PLM, Pennings RJE, Cremers CWRJ. Characterizing and distinguishing is the orthologue of the USH1G gene than that of the gene progressive phenotypes in nonsyndromic autosomal dominant hearing impairment. Audiol Med. 2003;1:37-46. for nonsyndromic hearing loss in the present family. Al- 12. Pennings RJE, Huygen PLM, Van Camp G, Cremers CWRJ. A review of progres- ready 3 genes have been found to be involved in both Usher sive phenotypes in nonsyndromic autosomal dominant hearing impairment. Au- syndrome and in nonsyndromic hearing loss.7,12,17,23-29 diol Med. 2003;1:47-55. 13. Elfenbein JL, Fisher RA, Wei S, et al. Audiologic aspects of the search for DFNA20: Therefore, the identification of the disease-causing muta- a gene causing late-onset, progressive, sensorineural hearing loss. Ear Hear. 2001; tions is needed to elucidate whether DFNA20 and DFNA26 22:279-288. are caused by mutations in the same gene. This will also 14. De Leenheer EMR, Huygen PLM, Coucke PJ, Admiraal RJ, Van Camp G, Crem- ers CWRJ. Longitudinal and cross-sectional phenotype analysis in a new, large show whether the USH1G gene is involved. Dutch DFNA2/KCNQ4 family. Ann Otol Rhinol Laryngol. 2002;111:267-274. The present research was successful in mapping the 15. Kong A, Gudbjartsson DF, Sainz J, et al. A high-resolution recombination map of the human genome. Nat Genet. 2002;31:241-247. causative gene for hearing loss in a Dutch family to the 16. Miller SA, Dykes DD, Polesky HF. A simple salting out procedure for extracting DFNA20/26 interval and in refining its critical region. The DNA from human nucleated cells. Nucleic Acids Res. 1988;16:1215. present report is the second to provide detailed tone and 17. Martini A. European Concerted Action Project On Genetic Hearing Impairment: Infoletter 2. Available at: http://web.unife.it/progetti/gendeaf/hear/infoletters speech audiometric data for this locus. The publication of /Info_02.PDF. Accessed November 1, 2003. additional data available from other DFNA20/26 families 18. Kunst HPM, Huybrechts C, Marres HAM, Huygen PLM, Van Camp G, Cremers is needed to improve phenotypic comparison. Clinical fea- CWRJ. The phenotype of DFNA13/COL11A2: nonsyndromic autosomal dominant mid-frequency and high-frequency sensorineural hearing impairment. Am tures of the 2 available families show some audiometric simi- J Otol. 2000;21:181-187. larity. However, members of the Dutch family appear to be 19. Morell RJ, Friderici KH, Wei S, Elfenbein JL, Friedman TB, Fisher RA. A new locus for late-onset, progressive, hereditary hearing loss DFNA20 maps to 17q25. more severely affected at an earlier age. As yet, no gene or Genomics. 2000;63:1-6. disease-causing mutations have been identified for DFNA20/ 20. Mustapha M, Chouery E, Torchard-Pagnez D, et al. A novel locus for Usher syn- 26. It has been previously suggested that DFNA20 might drome type I, USH1G, maps to chromosome 17q24-25. Hum Genet. 2002;110: 13 348-350. represent a suitable model of presbyacusis. The present 21. Yang T, Smith RJH. A novel locus DFNA26 maps to chromosome 17q25 in two data, however, do not demonstrate any striking similarity unrelated families with progressive autosomal dominant hearing loss. Abstract between the phenotype of DFNA20/26 and presbyacusis. 1655 presented at: American Society of Human Geneties (ASHG) meeting; Oc- tober 3-7, 2000; Philatelphia, Pa. 22. Roderick TH. Position of jackson shaker. Mouse News Lett. 1972;47:37. Submitted for publication October 30, 2002; final revision 23. Liu XZ, Walsh J, Mburu P et al. Mutations in the myosin VIIA gene cause nonsyndromic recessive deafness. Nat Genet. 1997;16:188-190. received June 17, 2003; accepted August 12, 2003. 24. Weil D, Kussel P, Blanchard S, et al. The autosomal recessive isolated deafness, This study was financially supported by the Nether- DFNB2, and the Usher 1B syndrome are allelic defects of the myosin-VIIA gene. lands Organization for Health Research and Development Nat Genet. 1997;16:191-193. 25. Bitner-Glindzicz M, Lindley KJ, Rutland P, et al. A recessive contiguous gene de- (project No. 920-03-100), the Hague; and the Heinsius letion causing infantile hyperinsulinism, enteropathy and deafness identifies the Houbolt Foundation and the Nijmegen Otorhinolaryngol- Usher type 1C gene. Nat Genet. 2000;26:56-60. ogy Foundation, Nijmegen, the Netherlands. 26. Bork JM, Peters LM, Riazuddin S, et al. Usher syndrome 1D and nonsyndromic autosomal recessive deafness DFNB12 are caused by allelic mutations of the novel We acknowledge the contributions of Wendy H. M. de cadherin-like gene CDH23. Am J Hum Genet. 2001;68:26-37. Jong and Janneke J. C. van Lith-Verhoeven to the genetic 27. Bolz H, von Brederlow B, Ramirez A, et al. Mutation of CDH23, encoding a new member of the cadherin gene family, causes Usher syndrome type 1D. Nat Genet. analysis and of Marion H. F. B. Bohnen to the clinical part 2001;27:108-112. of this study. 28. Petit C, Levilliers J, Hardelin JP. Molecular genetics of hearing loss. Annu Rev Corresponding author and reprints: Martijn H. Kem- Genet. 2001;35:589-646. 29. Ahmed ZM, Smith TN, Riazuddin S, et al. Nonsyndromic recessive deafness perman, MD, Department of Otorhinolaryngology, Univer- DFNB18 and Usher syndrome type IC are allelic mutations of USHIC. Hum Genet. sity Medical Center Nijmegen, PO Box 9101, 6500 HB Ni- 2002;110:527-531.

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