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BackgroundOtitis media (OM) susceptibility has significant heritability; however, the role of rare variants in OM is mostly unknown. Our goal is to identify novel rare variants that confer OM susceptibility.MethodsWe performed exome and Sanger sequencing of >1000 DNA samples from 551 multiethnic families with OM and unrelated individuals, RNA-sequencing and microbiome sequencing and analyses of swabs from the outer ear, middle ear, nasopharynx and oral cavity. We also examined protein localisation and gene expression in infected and healthy middle ear tissues.ResultsA large, intermarried pedigree that includes 81 OM-affected and 53 unaffected individuals cosegregates two known rare A2ML1 variants, a common FUT2 variant and a rare, novel pathogenic variant c.1682A>G (p.Glu561Gly) within SPINK5 (LOD=4.09). Carriage of the SPINK5 missense variant resulted in increased relative abundance of Microbacteriaceae in the middle ear, along with occurrence of Microbacteriaceae in the outer ear and oral cavity but not the nasopharynx. Eight additional novel SPINK5 variants were identified in 12 families and individuals with OM. A role for SPINK5 in OM susceptibility is further supported by lower RNA counts in variant carriers, strong SPINK5 localisation in outer ear skin, faint localisation to middle ear mucosa and eardrum and increased SPINK5 expression in human cholesteatoma.ConclusionSPINK5 variants confer susceptibility to non-syndromic OM. These variants potentially contribute to middle ear pathology through breakdown of mucosal and epithelial barriers, immunodeficiency such as poor vaccination response, alteration of head and neck microbiota and facilitation of entry of opportunistic pathogens into the middle ear.

Background: Hearing loss remains an important global health problem that is potentially addressed through early identification of a genetic etiology, which helps to predict outcomes of hearing rehabilitation such as cochlear implantation and also to mitigate the long-term effects of comorbidities. The identification of variants for hearing loss and detailed descriptions of clinical phenotypes in patients from various populations are needed to improve the utility of clinical genetic screening for hearing loss. Methods: Clinical and exome data from 15 children with hearing loss were reviewed. Standard tools for annotating variants were used and rare, putatively deleterious variants were selected from the exome data. Results: In 15 children, 21 rare damaging variants in 17 genes were identified, including: 14 known hearing loss or neurodevelopmental genes, 11 of which had novel variants, and three candidate genes IST1, CBLN3 and GDPD5, two of which were identified in children with both hearing loss and enlarged vestibular aqueducts. Patients with variants within IST1 and MYO18B had poorer outcomes after cochlear implantation. Conclusion: Our findings highlight the importance of identifying novel variants and genes in ethnic groups that are understudied for hearing loss.

BACKGROUND: Otitis media (OM) susceptibility has significant heritability, however the role of rare variants in OM is mostly unknown. Our goal is to identify novel rare variants that confer OM susceptibility. METHODS: We performed exome and Sanger sequencing of >1,000 DNA samples from 551 multi-ethnic families with OM and unrelated individuals, RNA-sequencing, and microbiome sequencing and analyses of swabs from the outer ear, middle ear, nasopharynx and oral cavity. We also examined protein localization and gene expression in infected and healthy middle ear tissues. RESULTS: A large, intermarried pedigree that includes 81 OM-affected and 53 unaffected individuals co-segregates two known rare A2ML1 variants, a common FUT2 variant and a rare, novel pathogenic variant c.1682A>G (p.Glu561Gly) within SPINK5 (LOD=4.09). Carriage of the SPINK5 missense variant resulted in increased relative abundance of Microbacteriaceae in the middle ear, along with occurrence of Microbacteriaceae in the outer ear and oral cavity but not the nasopharynx. Eight additional novel SPINK5 variants were identified in twelve families and individuals with OM. A role for SPINK5 in OM susceptibility is further supported by lower RNA counts in variant carriers, strong SPINK5 localization in outer ear skin, faint localization to middle ear mucosa and eardrum, and increased SPINK5 expression in human cholesteatoma. CONCLUSION: SPINK5 variants confer susceptibility to non-syndromic OM. These variants potentially contribute to middle ear pathology through breakdown of mucosal and epithelial barriers, immunodeficiency such as poor vaccination response, alteration of head and neck microbiota, and facilitation of entry of opportunistic pathogens into the middle ear.

A genetic basis for otitis media is established, however, the role of rare variants in disease etiology is largely unknown. Previously a duplication variant within A2ML1 was identified as a significant risk factor for otitis media in an indigenous Filipino population and in US children. In this report exome and Sanger sequencing was performed using DNA samples from the indigenous Filipino population, Filipino cochlear implantees, US probands, Finnish, and Pakistani families with otitis media. Sixteen novel, damaging A2ML1 variants identified in otitis media patients were rare or low-frequency in population-matched controls. In the indigenous population, both gingivitis and A2ML1 variants including the known duplication variant and the novel splice variant c.4061 + 1 G>C were independently associated with otitis media. Sequencing of salivary RNA samples from indigenous Filipinos demonstrated lower A2ML1 expression according to the carriage of A2ML1 variants. Sequencing of additional salivary RNA samples from US patients with otitis media revealed differentially expressed genes that are highly correlated with A2ML1 expression levels. In particular, RND3 is upregulated in both A2ML1 variant carriers and high-A2ML1 expressors. These findings support a role for A2ML1 in keratinocyte differentiation within the middle ear as part of otitis media pathology and the potential application of ROCK inhibition in otitis media.

To identify genetic and environmental risk factors for otitis media in an indigenous Filipino population.Cross-sectional study.Indigenous Filipino community.Clinical history and information on breastfeeding, tobacco smoke exposure, and swimming were obtained from community members. Heads of households were interviewed for family history and personal beliefs on ear health. Height and weight were measured. Otoscopic findings were described for the presence and character of perforation or discharge. An A2ML1 duplication variant that confers otitis media susceptibility was Sanger sequenced in all DNA samples. Co-occurrence of middle ear bacteria detected by 16S rRNA gene sequencing was determined according to A2ML1 genotype and social cluster.The indigenous Filipino population has a ~50% prevalence of otitis media. Young age was associated with otitis media (4 age strata; P = .004); however, age was nonsignificant as a bistratal or continuous variable. There was no association between otitis media and sex, body mass index, breastfeeding, tobacco exposure, or deep swimming. In multivariate analyses, A2ML1 genotype is the strongest predictor of otitis media, with an odds ratio of 3.7 (95% confidence interval: 1.3-10.8; P = .005). When otitis media diagnoses were plotted across ages, otitis media was observed within the first year of life, and chronic otitis media persisted up to adulthood, particularly in A2ML1-variant carriers.Among indigenous Filipinos, A2ML1 genotype is the primary risk factor for otitis media and main determinant of disease progression, although age, the middle ear microbiome, and social clusters might modulate the effect of the A2ML1 genotype.

Non-secretor status due tohomozygosity for the commonFUT2 variant c. 461G> A(p. Trp154*) is associated witheither risk for autoimmune diseases or protection against viral diarrhea and HIV. We determined the role of FUT2 in otitis media susceptibility by obtaining DNA samples from 609 multi-ethnic families and simplex case subjectswith otitis media. Exome and Sanger sequencing, linkage analysis, and Fisher exact and transmission disequilibrium tests (TDT) were performed. The common FUT2 c. 604C> T (p. Arg202*) variant co-segregates with otitismedia in a Filipino pedigree (LOD = 4.0). Additionally, a rare variant, c. 412C> T (p. Arg138Cys), is associated with recurrent/ chronic otitismedia in European-American children (p = 1.2310(-5)) and US trios (TDT p = 0.01). The c. 461G> A (p. Trp154*) variant was also overtransmitted in US trios (TDT p = 0.01) and was associated with shifts inmiddle ear microbiota composition (PERMANOVA p 20 were combined, FUT2 variantswere over-transmitted in trios (TDTp = 0.001). Fut2 is transiently upregulated inmouse middle ear after inoculation withnon-typeable Haemophilus influenzae. Four FUT2 variants-namely p. Ala104Val, p. Arg138Cys, p. Trp154*, and p. Arg202*-reduced A antigen in mutant-transfected COS-7 cells, while the nonsense variants also reduced FUT2 protein levels. Common and rare FUT2 variants confer susceptibility to otitis media, likely by modifying the middle ear microbiome through regulation of A antigen levels in epithelial cells. Our familiesdemonstratemarked intra-familial genetic heterogeneity, suggesting thatmultiple combinations of common and rare variants plus environmental factors influence the individual otitis media phenotype as a complex trait.

A duplication variant within the middle ear-specific gene A2ML1 cosegregates with otitis media in an indigenous Filipino pedigree (LOD score = 7.5 at reduced penetrance) and lies within a founder haplotype that is also shared by 3 otitis-prone European-American and Hispanic-American children but is absent in non-otitis-prone children and62,000 next-generation sequences. We identified seven additional A2ML1 variants in six otitis-prone children. Collectively, our studies support a role for A2ML1 in the pathophysiology of otitis media.

Background Previously rare A2ML1 variants were identified to confer otitis media susceptibility in an indigenous Filipino community and in otitis-prone US children. The goal of this study is to describe differences in the middle ear microbiome between carriers and non-carriers of an A2ML1 duplication variant that increases risk for chronic otitis media among indigenous Filipinos with poor health care access. Methods Ear swabs were obtained from 16 indigenous Filipino individuals with chronic otitis media, of whom 11 carry the A2ML1 duplication variant. Ear swabs were submitted for 16S rRNA gene sequencing. Results Genotype-based differences in microbial richness, structure, and composition were identified, but were not statistically significant. Taxonomic analysis revealed that the relative abundance of the phyla Fusobacteria and Bacteroidetes, and genus Fusobacterium were nominally increased in carriers compared to non-carriers, but were non-significant after correction for multiple testing. We also detected rare bacteria including Oligella that was reported only once in the middle ear. Conclusions These findings suggest that A2ML1-related otitis media susceptibility may be mediated by changes in the middle ear microbiome. Knowledge of middle ear microbial profiles according to genetic background can be potentially useful for therapeutic and prophylactic interventions for otitis media and can guide public health interventions towards decreasing otitis media prevalence within the indigenous Filipino community. Electronic supplementary material The online version of this article (doi:10.1186/s40249-016-0189-7) contains supplementary material, which is available to authorized users.

Background: Hearing loss in children if undetected can lead to delay in speech and language development, social and emotional problems, and academic difficulties. The importance of screening of school-age children to detect hearing loss cannot be overemphasized. In the Philippines, there is no single uniform program for hearing screening in school children. This study examines a device that has been proposed to be used for mass hearing screening. The device is called a hand-held hearing screener (Siemens Hear Check Navigator) that displays three colors as a result: green for pass or no hearing loss; yellow and red for fail or possible hearing loss. The objective of the study is to determine the accuracy of the hand-held hearing screener device as a hearing screening tool to be used in the school setting for first graders. Methodology: This is an analytical cross-sectional study among Grade I students conducted in three schools in Metro Manila, Philippines, during regular school days. Each child passed through five stations: collection of demographic data, otoscopy, screening with hearing screener device, screening audiometry and counseling. Ambient sound was maintained at 50 dBA or less during testing. The hearing screener device presents pure tones of 35 dbHL, 55 dbHL, and 75 dBHL at test frequencies 375 Hz, 1000 Hz, and 3000 Hz. Its results were: green light which was considered as “absence of hearing loss”, and yellow and red lights which were considered as “presence of hearing loss”. The results of the hearing screener device test were used to determine its sensitivity and specificity, using the results of the screening audiometry as gold standard. Results: A total of 418 grade one elementary school children were included in the study. The hand-held screener was found to have high specificity of 97.8% (yellow results) to 99.6% (red results) but low sensitivity of 9.1% (red results) to 16.7% (yellow results). Positive predictive values for red and yellow results are 26.1% and 50% respectively. The accuracy of the red results of the hearing screener device is 95.9% and the accuracy of the yellow results of the hearing screener is 94.2%. Conclusion: Based on this study, the hearing screener device has low sensitivity in detecting the presence of possible hearing loss in children when used in the school setting. Thus, the hearing screener device is not an ideal tool to use in the mass hearing screening of children in the school setting where there are no soundproof booths and with significant levels of ambient sound. Its excellent specificity may support its use, not for screening, but possibly for confirmation of the absence of hearing loss. For screening, its value lies in its high specificity, good accuracy rates and significant positive predictive values in detecting possible hearing loss, thus warranting a referral for a definitive hearing test. The significant level of ambient sound in this study’s conduction is a limitation and may account for the low sensitivity of the hearing screener device. More studies with fewer limitations are needed that will explore and validate the use of the hearing screener device in children in the school setting.