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BACKGROUND: Individuals with thiamine-responsive megaloblastic anemia (TRMA) mainly manifest macrocytic anemia, sensorineural deafness, ocular complications, and nonautoimmune diabetes. Macrocytic anemia and diabetes may be responsive to high-dosage thiamine treatment, in contrast to sensorineural deafness. Little is known about the efficacy of thiamine treatment on ocular manifestations. CASES PRESENTATION: Our objective is to report data from four Italian TRMA patients: in Cases 1, 2 and 3, the diagnosis of TRMA was made at 9, 14 and 27 months. In 3 out of 4 subjects, thiamine therapy allowed both normalization of hyperglycemia, with consequent insulin suspension, and macrocytic anemia. In all Cases, thiamine therapy did not resolve the clinical manifestation of deafness. In Cases 2 and 3, follow-up showed no blindness, unlike Case 4, in which treatment was started for megaloblastic anemia at age 7 but was increased to high doses only at age 25, when the genetic diagnosis of TRMA was performed. CONCLUSIONS: Early institution of high-dose thiamine supplementation seems to prevent the development of retinal changes and optic atrophy in TRMA patients. The spectrum of clinical manifestations is broad, and it is important to describe known Cases to gain a better understanding of this rare disease.
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Anemia Megaloblástica , Surdez , Diabetes Mellitus , Perda Auditiva Neurossensorial , Humanos , Criança , Adulto , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/tratamento farmacológico , Diabetes Mellitus/genética , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/tratamento farmacológico , Perda Auditiva Neurossensorial/genética , Tiamina/uso terapêutico , Anemia Megaloblástica/diagnóstico , Anemia Megaloblástica/tratamento farmacológico , Diagnóstico Precoce , Surdez/complicações , Surdez/tratamento farmacológicoRESUMO
With more than 466 million people affected, hearing loss represents the most common sensory pathology worldwide. Despite its widespread occurrence, much remains to be explored, particularly concerning the intricate pathogenic mechanisms underlying its diverse phenotypes. In this context, metabolomics emerges as a promising approach. Indeed, lying downstream from molecular biology's central dogma, the metabolome reflects both genetic traits and environmental influences. Furthermore, its dynamic nature facilitates well-defined changes during disease states, making metabolomic analysis a unique lens into the mechanisms underpinning various hearing impairment forms. Hence, these investigations may pave the way for improved diagnostic strategies, personalized interventions and targeted treatments, ultimately enhancing the clinical management of affected individuals. In this comprehensive review, we discuss findings from 20 original articles, including human and animal studies. Existing literature highlights specific metabolic changes associated with hearing loss and ototoxicity of certain compounds. Nevertheless, numerous critical issues have emerged from the study of the current state of the art, with the lack of standardization of methods, significant heterogeneity in the studies and often small sample sizes being the main limiting factors for the reliability of these findings. Therefore, these results should serve as a stepping stone for future research aimed at addressing the aforementioned challenges.
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Surdez , Perda Auditiva , Animais , Humanos , Reprodutibilidade dos Testes , Perda Auditiva/diagnóstico , Surdez/genética , Metabolômica , MetabolomaRESUMO
Brain-derived neurotrophic factor (BDNF) has a crucial function in the central nervous system and in sensory structures including olfactory and auditory systems. Many studies have highlighted the protective effects of BDNF in the brain, showing how it can promote neuronal growth and survival and modulate synaptic plasticity. On the other hand, conflicting data about BDNF expression and functions in the cochlear and in olfactory structures have been reported. Several clinical and experimental research studies showed alterations in BDNF levels in neurodegenerative diseases affecting the central and peripheral nervous system, suggesting that BDNF can be a promising biomarker in most neurodegenerative conditions, including Alzheimer's disease, shearing loss, or olfactory impairment. Here, we summarize current research concerning BDNF functions in brain and in sensory domains (olfaction and hearing), focusing on the effects of the BDNF/TrkB signalling pathway activation in both physiological and pathological conditions. Finally, we review significant studies highlighting the possibility to target BDNF as a biomarker in early diagnosis of sensory and cognitive neurodegeneration, opening new opportunities to develop effective therapeutic strategies aimed to counteract neurodegeneration.
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Background and Objectives: Midlife hearing loss (HL) has been considered as a major modifiable risk factor for a later-life progression to dementia. Our aim was to detect a link between precocious sensorineural hearing loss (SNHL) and mild cognitive impairment (MCI) and their association to putative risk factors for a common pathology. Materials and methods: In this study, a retrospective case-control study was carried out. A total of 112 patients were enrolled as following: 81 patients with bilateral SNHL and 31 subjects with normal hearing, whose ages ranged from 50 to 65 years. Both groups performed pure tone audiometry, a tinnitus handicap inventory (THI), Mini-Mental State examination (MMSE), and the Montreal Cognitive Assessment (MoCA), Hospital Anxiety and Depression Scale (HADS-A and HADS-D). Results: The mean age was 58 ± 5.2 in SNHL patients and 53.2 ± 4.8 in the control group. The mean pure tone average in the SNHL group was 40.2 ± 18.7 dB HL on the right side and 41.2 ± 17.2 dB HL on the left side, while in the control group it was 12.5 ± 2.8 dB HL on right side and 12.4 ± 3.1 dB HL on left side. About 64% of patients with SNHL exhibited comorbidities, and the most common condition was hypertension. Altered MoCA test scores were significantly related to the pure tone averages in patients with SNHL compared to the control group (p = 0.0004), while the differences in the HADS-A and HADS-D were not significant. Furthermore, a significant correlation was observed in SNHL patients between an altered MoCA test and hypercholesterolemia (p = 0.043). Conclusions: Hearing impairment and screening tests to detect MCI should be considered in the midlife in order to carry out strategies to prevent the progression to dementia. Hypertension and hypercholesterolemia are two risk factors in the development of endothelial dysfunction, oxidative stress, and vascular inflammation, and may represent the common pathology linking the inner ear and brain damage.
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Disfunção Cognitiva , Surdez , Demência , Perda Auditiva Neurossensorial , Perda Auditiva , Hipercolesterolemia , Humanos , Pessoa de Meia-Idade , Idoso , Estudos Retrospectivos , Estudos de Casos e Controles , Perda Auditiva Neurossensorial/complicações , Perda Auditiva Neurossensorial/diagnóstico , Disfunção Cognitiva/complicaçõesRESUMO
Permanent childhood hearing impairment (PCHI) represents the most frequent sensory pathology at birth. PCHI has a relevant psychological impact on the life of both the affected children and their families. Thus, the aim of this work is to explore the degree of parental distress felt by mothers of a deaf or hard-of-hearing child, to determine if this stress is associated with variables related to the children's health (e.g., the severity of hearing loss, presence of other conditions, difficulty with treatment options, difficulty with rehabilitation) or family characteristics such as socio-economic and educational status. The study used the Parenting Stress Index-Short Form (PSI-SF) questionnaire administered to mothers. The results were analyzed in relation to variables such as parents' education level, number of children, severity of hearing loss, presence of other chronic conditions, presence of cognitive delay, familiarity with hearing loss, time of diagnosis, use of prosthetics, and start in a rehabilitation program. The data indicate a correlation between maternal stress levels and low-educational levels, as well as the presence of congenital infections and cognitive delay. These results highlight the need for a comprehensive physical and psychological approach for hearing-impaired children, as stress factors can affect the adherence to effective rehabilitation.
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BACKGROUND: Currently, the novel coronavirus (SARS-CoV-2) causes an acute respiratory illness named COVID-19 and is a controversial risk factor for hearing loss (HL). Herein, we aim to describe the associated symptoms and to evaluate hearing function in the COVID-19 pediatric population. METHODS: A retrospective cross-sectional observational study was carried out on 37 children who contracted COVID-19 infection with no previous audio-vestibular disorders. Clinical data on the infections were collected, and an audiological assessment of all affected children was performed by using different diagnostic protocols according to their age. RESULTS: Fever, upper respiratory and gastrointestinal manifestations were common presentations of infection. Audiological function was normal in 30 (81.08%) children, while 7 children showed an increased hearing threshold: 6 (16.21%) had transient conductive hearing loss (CHL) due to middle ear effusion and normalized at the follow-up and 1 had sensorineural hearing loss (SNHL). A single child was affected by bilateral SNHL (2.7%); however, he underwent a complete audiological work-up leading to a diagnosis of genetic HL due to a MYO6 gene mutation which is causative of progressive or late onset SNHL. CONCLUSIONS: HL needs to be considered among the manifestations of COVID-19 in children, nevertheless, we found cases of transient CHL. The onset of HL during or following COVID-19 infection does not eliminate the indication for maintaining audiological surveillance and audiological work-ups, including genetic diagnosis, to avoid the risk of mistaking other causes of HL.
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Background: Objectives of the present work were to analyze the prevalence of hearing loss in our population of screened newborns during the first 9 years of the universal newborn hearing screening (UNHS) program at University Hospital Sassari (Italy) (AOU Sassari), to analyze the risk factors involved, and to analyze our effectiveness in terms of referral rates and dropout rates. Methods: Monocentric retrospective study whose target population included all the newborns born or referred to our hospital between 2011 and 2019. Results: From 2011 to 2019, a total of 11,688 babies were enrolled in our screening program. In total, 3.9‱ of wellborn babies and 3.58% of neonatal intensive care unit (NICU) babies had some degree of hearing loss. The most frequently observed risk factors among non-NICU babies were family history of hearing loss (3.34%) and craniofacial anomalies (0.16%), among NICU babies were low birth weight (54.91%) and prematurity (24.33%). In the multivariate analysis, family history of hearing loss (p < 0.001), NICU (p < 0.001), craniofacial anomalies (p < 0.001), low birth weight (<1500 g) (p = 0.04) and HIV (p = 0.03) were confirmed as risk factors. Conclusions: Our data are largely consistent with the literature and most results were expected, one relevant exception being the possible role of NICU as a confounding factor and the limited number of risk factors confirmed in the multivariate analysis.
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BACKGROUND: An early hearing detection and intervention program (EHDI) is the first step for the habilitation of children with permanent hearing impairment (PHI). Actually, early intervention programs have increasingly shifted toward family involvement, emphasizing that the child's family should take an active role in the habilitation process. Therefore, familiar empowerment is the best way to improve a child's emerging abilities. The aim of this study was to investigate parental self-efficacy beliefs and involvement as well as the language skills of deaf or hard of hearing DHH children who were habilitated with hearing aids and followed using the T.A.T.A web app (NeonaTal Assisted TelerehAbilitation), an example of asynchronous telepractice. METHODS: The study describes the early stages of the habilitation program of 15 PHI children followed through the T.A.T.A. web app, which empowers families through a weekly questionnaire submitted during the first 270 to 360 days of their child's life, for 14 weeks. The family involvement rate scale (FIRS) was used to evaluate parental compliance, and all children received in-person visits at the beginning and at the end of the training period. RESULTS: The children showed greater auditory perceptual skills at the end of the training period on the basis of both the Infant Listening Progress Profile (ILiP) score and the Categories of Auditory Performance (CAP) and FIRS scales. In other words, the auditory skills improved with age as well as with parental participation. CONCLUSIONS: The T.A.T.A. web app promotes a proactive management and a tailored habilitation through an active familiar involvement, easily achieved in clinical routine and in emergency settings without additional costs.
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PURPOSE: Universal newborn hearing screening (UNHS) in the first month of life is crucial for facilitating both early hearing detection and intervention (EHDI) of significant permanent hearing impairment (PHI). In Campania region, UNHS has been introduced in 2003 by the Regional Council Resolution and started on January 2007. The aim of this paper is to update a previous article describing the performance of the program since its implementation in the period between 2013 and 2019. METHODS: A longitudinal retrospective study was carried at the Regional Reference Center III on 350,178 babies born in the analysis period. The paper reports the main results of overall coverage, referral rate, lost-to-follow-up rate,yield for PHI and shall determine various risk factor associations with hearing impairment RESULTS: In Campania region, 318,878 newborns were enrolled at I level, with a coverage rate of 91.06%, 301,818 (86.18%) Well Infant Nurseries (WIN) and 17,060 (5.35%) Neonatal Intensive Care Unit (NICU) babies. PHI was identified in 413 children, 288 (69.73%) bilaterally and 125 (30.26%) unilaterally. The overall cumulative incidence rate of PHI was 1.29 per 1000 live-born infants (95% CI 1.17-1.42) with a quite steady tendency during the whole study period. CONCLUSIONS: This study confirms the feasibility and effectiveness of UNHS in Campania region also in a setting with major socioeconomic and health organization restrictions.The program meets quality benchmarks to evaluate the progress of UNHS. Nowadays, it is possible to achieve an early diagnosis of all types of HL avoiding the consequences of hearing deprivation.
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Perda Auditiva , Triagem Neonatal , Criança , Audição , Perda Auditiva/diagnóstico , Perda Auditiva/epidemiologia , Testes Auditivos/métodos , Humanos , Lactente , Recém-Nascido , Triagem Neonatal/métodos , Estudos RetrospectivosRESUMO
BACKGROUND: People with cluster headache (CH) are frequently burdened by misdiagnosis or diagnostic delay. The peculiar somatic and behavioral changes characterizing patients with CH are not useful to improve diagnostic accuracy. In our clinical experience, we noticed a typical voice quality with low and croaking tone in patients with CH. In this cross-sectional study, we evaluated, by digital voice analysis, whether it is possible to identify typical voice quality characterizing patients with CH compared with healthy controls (HCs). Furthermore, to investigate whether putative differences in voice characteristics could be underpinned by constitutional aspects or pathological processes of vocal cords, subjects underwent a videolaryngostroboscopy. Smoking habits and alcohol consumption were specifically investigated. METHODS: After conducting digital recording of the voices from both patients with CH and HCs in a soundproof insulated cabin in the laboratory of the Audiology Department, a set of voice parameters was analyzed. We included the measures of fundamental frequency, calculations of jitter and shimmer, and noise-to-harmonics ratios as well as quantities related to the spectral tilt (i.e., H1-H2, H1-A1, H1-A2, and H1-A3) in 20 patients with CH and in 13 HCs. A videolaryngostroboscopy was performed in all subjects. RESULTS: Patients with CH, explored during the cluster bout period, showed significantly lower second harmonic (H1-H2) values compared with HCs (-6.9 ± 7.6 vs. 2.1 ± 6.7, p = 0.002), usually characterizing the so-called creaky voice. By using a laryngoscopy investigation, a significantly higher prevalence of mild to moderate vocal cord edema and laryngopharyngeal reflux signs were found in patients with CH (100% of patients with CH vs. 15% of HC, p < 0.001). CONCLUSION: Creaky phonation is a "physiological mode of laryngeal operation" usually underpinned by shortened and thickened vocal folds. Creaky voice phonation can be due to a vocal fold's reduced capability to become slack or flaccid secondary to vocal cord edema underpinned by laryngopharyngeal reflux affecting the phonatory mechanisms in patients with CH. The laryngopharyngeal reflux may represent a dysautonomic sign related to the increased parasympathetic tone during in-bout period, reinforcing the hypothesis of an extracranial autonomic dysfunction as part of CH clinical picture.
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Doenças do Sistema Nervoso Autônomo/fisiopatologia , Cefaleia Histamínica/fisiopatologia , Distúrbios da Voz/diagnóstico , Distúrbios da Voz/fisiopatologia , Qualidade da Voz/fisiologia , Adulto , Doenças do Sistema Nervoso Autônomo/diagnóstico , Cefaleia Histamínica/diagnóstico , Estudos Transversais , Humanos , Laringoscopia , Masculino , Pessoa de Meia-IdadeRESUMO
OBJECTIVES: Tinnitus is a common symptom largely impactful on quality of life, especially in the elderly. Our aim was to evaluate the efficacy of self-administered screening tests to correlate the severity of subjective perception of tinnitus with emotional disorders and the overall cognitive status. METHODS: Patients aged ≥ 55 years with chronic tinnitus were recruited and submitted to a complete audiological evaluation; Tinnitus Handicap inventory (THI); Hospital Anxiety and Depression Scale (HADS-A and HADS-D) and Mini-Mental State Examination (MMSE). Demographic and audiological features of patients with and without cognitive impairment (MMSE score cut-off of 24/30) were analyzed in order to reveal the relationship among tinnitus, emotional disorders, and cognitive dysfunction. RESULTS: 102 patients were recruited (mean age: 70.4 ± 9.6). THI score was directly related to HADS-A score (r = .63) HADS-D score (r = .66), whereas there was no relationship between tinnitus severity and MMSE (r = .13). CI and n-CI groups did not differ in the characteristics of tinnitus (p > .05), however, hearing threshold (p = .049) and anxious depressive traits measured with HADS-A (p = .044) and HADS-D (p = .016) were significantly higher in the group with cognitive impairment. Furthermore, age ≥ 75 years (p = .002, OR = 13.8), female sex (p = .032; OR = 6.5), severe hearing loss (p = .036; OR = 2.3), and anxiety (p = .029; OR = 9.2) resulted risk factors for CI. Therefore, in CI group MMSE score was inversely related to age (r = -.84). CONCLUSIONS: Cognitive impairment and psychiatric discomfort should be considered in tinnitus patients, related to increasing age, female sex, and severe hearing loss. Thus, self-administered questionnaires can be useful in addressing clinical approach.
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Zumbido , Idoso , Idoso de 80 Anos ou mais , Ansiedade , Transtornos de Ansiedade , Cognição , Feminino , Humanos , Pessoa de Meia-Idade , Qualidade de Vida , Zumbido/epidemiologiaRESUMO
BACKGROUND: The aim of this study was to compare, in users of bimodal cochlear implants, the performance obtained using their own hearing aids (adjusted with the standard NAL-NL1 fitting formula) with the performance using the Phonak Naìda Link Ultra Power hearing aid adjusted with both NAL-NL1 and a new bimodal system (Adaptive Phonak Digital Bimodal (APDB)) developed by Advanced Bionics and Phonak Corporations. METHODS: Eleven bimodal users (Naìda CI Q70 + contralateral hearing aid) were enrolled in our study. The users' own hearing aids were replaced with the Phonak Naìda Link Ultra Power and fitted following the new formula. Speech intelligibility was assessed in quiet and noisy conditions, and comparisons were made with the results obtained with the users' previous hearing aids and with the Naída Link hearing aids fitted with the NAL-NL1 generic prescription formula. RESULTS: Using Phonak Naìda Link Ultra Power hearing aids with the Adaptive Phonak Digital Bimodal fitting formula, performance was significantly better than that with the users' own rehabilitation systems, especially in challenging hearing situations for all analyzed subjects. CONCLUSIONS: Speech intelligibility tests in quiet settings did not reveal a significant difference in performance between the new fitting formula and NAL-NL1 fittings (using the Naída Link hearing aids), whereas the performance difference between the two fittings was very significant in noisy test conditions.
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INTRODUCTION: Tinnitus is a common and disabling symptom often associated with hearing loss. While clinical practice frequently shows that a certain degree of psychological discomfort often characterizes tinnitus suffers, it has been recently suggested in adults as a determining factor for cognitive decline affecting attention and memory domains. The aim of our systematic review was to provide evidence for a link between tinnitus, psychological distress, and cognitive dysfunction in older patients and to focus on putative mechanisms of this relationship. METHODS: We performed a systematic review, finally including 192 articles that were screened. This resulted in 12 manuscripts of which the full texts were included in a qualitative analysis. RESULTS: The association between tinnitus and psychological distress, mainly depression, has been demonstrated in older patients, although only few studies addressed the aged population. Limited studies on cognitive dysfunction in aged patients affected by chronic tinnitus are hardly comparable, as they use different methods to validate cognitive impairment. Actual evidence does not allow us with certainty to establish if tinnitus matters as an independent risk factor for cognitive impairment or evolution to dementia. CONCLUSION: Tinnitus, which is usually associated with age-related hearing loss, might negatively affect emotional wellbeing and cognitive capacities in older people, but further studies are required to improve the evidence.
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OBJECTIVE: To identify children with postnatal hearing loss, a structured monitoring system is needed. The goal of this study was to describe a targeted surveillance program in Italy to identify children with postnatal hearing loss. METHODS: Between January, 2013, and December, 2016, all children who received bilateral 'pass' result at the newborn hearing screening, and who were identified as having at least one risk factor, were referred for targeted surveillance. The hospital records of these children were retrieved. RESULTS: Among children enrolled, 66 were identified with permanent hearing loss. The most frequent risk factors were family history (35%), prematurity (25.5%), low birthweight (19.2%), severe hyperbilirubinemia (19%), prolonged ventilation (15%) and congenital infection (12.5%). CONCLUSIONS: An audiological surveillance program in newborns who 'pass' in neonatal screening, but have risk factors, is effective in identifying permanent postnatal hearing disorders.
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Perda Auditiva , Triagem Neonatal , Criança , Perda Auditiva/diagnóstico , Perda Auditiva/epidemiologia , Testes Auditivos , Humanos , Recém-Nascido de Baixo Peso , Recém-Nascido , Encaminhamento e Consulta , Fatores de RiscoRESUMO
PURPOSE: Usher syndrome (USH) is an autosomal recessive disorder characterized by congenital sensorineural hearing impairment and retinitis pigmentosa. Classification distinguishes three clinical types of which type I (USH1) is the most severe, with vestibular dysfunction as an added feature. To date, 15 genes and 3 loci have been identified with the USH1G gene being an uncommon cause of USH. We describe an atypical USH1G-related phenotype caused by a novel homozygous missense variation in a patient with profound hearing impairment and relatively mild retinitis pigmentosa, but no vestibular dysfunction. METHODS: A 26-year-old female patient with profound congenital sensorineural hearing loss, nyctalopia and retinitis pigmentosa was studied. Audiometric, vestibular and ophthalmologic examination was performed. A panel of 13 genes was tested by next-generation sequencing (NGS). RESULTS: While the hearing loss was confirmed to be profound, the vestibular function resulted normal. Although typical retinitis pigmentosa was present, the age at onset was unusually late for USH1 syndrome. A novel homozygous missense variation (c.1187T>A, p.Leu396Gln) in the USH1G gene has been identified as causing the disease in our patient. CONCLUSIONS: Genetic and phenotypic heterogeneity are very common in both isolated and syndromic retinal dystrophies and sensorineural hearing loss. Our findings widen the spectrum of USH allelic disorders and strength the concept that variants in genes that are classically known as underlying one specific clinical USH subtype might result in unexpected phenotypes.
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Mutação de Sentido Incorreto/genética , Proteínas do Tecido Nervoso/genética , Síndromes de Usher/genética , Adulto , Análise Mutacional de DNA , Feminino , Genótipo , Testes Auditivos , Humanos , Imagem Multimodal , Linhagem , Fenótipo , Síndromes de Usher/diagnósticoRESUMO
Background and Aim: Cytomegalovirus (CMV) is the main cause of congenital infection in developed countries leading to deafness but the burden of sensorineural hearing loss (SNHL) in asymptomatic children remains incompletely characterized. Aim of this study was to evaluate the long-term audiological outcome in this group of patients. Methods: Consecutive neonates with congenital CMV infection were followed from 2002 to 2018. Patients were considered asymptomatic if free from any clinical and instrumental impairment at referral and underwent serial clinical exams, audiological evaluations and CMV-PCR determinations. Results: A cohort of 258 children was analyzed and the disease onset was asymptomatic in 125 (48%) infants. Among these, we studied 102 patients with a follow-up longer than 1 year and a median observation period of 2.8 years (range: 1-10.3 years). No patient developed a stable delayed SNHL but only 14 (14%) presented a variable hearing impairment, seven of which bilateral. The unstable SNHL was mild in 12 infants and moderate in two. Patients with fluctuating SNHL had significantly higher urine viral load (p 0.002) and more often positive viremia (p 0.015) than babies with stable normal hearing. Conclusions: CMV infected, asymptomatic neonates have a low risk of transient SNHL later in infancy. Positive viremia and high urine viral load at onset are significant risk factors for delayed fluctuating SNHL. These data are relevant for an appropriate follow up plan of these patients.
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Sensorineural hearing loss is a heterogeneous disease caused by mutations in many genes. However, in the presence of enlarged vestibular aqueduct, it is frequently associated with mutations in the solute carrier family 26 member 4 (SLC26A4), a gene causative of a syndromic form (Pendred) as well as a non-syndromic form of hearing loss (DFNB4). We describe a clinical case presenting bilateral sensorineural hearing loss and enlarged vestibular aqueduct in which a novel homozygous SLC26A4 mutation was identified. Despite a late diagnosis of hearing loss, a peculiar rehabilitation therapy strategy was identified that provided excellent results.
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Códon sem Sentido/genética , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/reabilitação , Transportadores de Sulfato/genética , Aqueduto Vestibular/anormalidades , Criança , Feminino , Perda Auditiva Neurossensorial/genética , Homozigoto , HumanosRESUMO
Sensorineural hearing loss is a very diffuse pathology (about 1/1000 born) with several types of transmission. X-linked hearing loss accounts for approximately 1% - 2% of cases of non-syndromic forms, as well as for many syndromic forms. To date, six loci (DFNX1-6) and five genes (PRPS1 for DFNX1, POU3F4 for DFNX2, SMPX for DFNX4, AIFM1 for DFNX5 and COL4A6 for DFNX6) have been identified for X-linked non-syndromic hearing loss. For the syndromic forms, at least 15 genes have been identified, some of which are also implicated in non-syndromic forms. Moreover, some syndromic forms, presenting large chromosomal deletions, are associated with mental retardation too. This review presents an overview of the currently known genes related to X-linked hearing loss with the support of the most recent literature. It summarizes the genetics and clinical features of X-linked hearing loss to give information useful to realize a clear genetic counseling and an early diagnosis. It is important to get an early diagnosis of these diseases to decide the investigations to predict the evolution of the disease and the onset of any other future symptoms. This information will be clearly useful for choosing the best therapeutic strategy. In particular, regarding audiological aspects, this review highlights risks and benefits currently known in some cases for specific therapeutic intervention.
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BACKGROUND: Sensorineural hearing impairment is a common pathological manifestation in patients affected by X-linked intellectual disability. A few cases of interstitial deletions at Xq21 with several different phenotypic characteristics have been described, but to date, a complete molecular characterization of the deletions harboring disease-causing genes is still missing. Thus, the aim of this study is to realize a detailed clinical and molecular analysis of a family affected by syndromic X-linked hearing loss with intellectual disability. RESULTS: Clinical analyses revealed a very complex phenotype that included inner ear malformations, vestibular problems, choroideremia and hypotonia with a peculiar pattern of phenotypic variability. Genomic analysis revealed, for the first time, the presence of two close interstitial deletions in the Xq21.1-21.3, harboring 11 protein coding, 9 non-coding genes and 19 pseudogenes. Among these, 3 protein coding genes have already been associated with X-linked hearing loss, intellectual disability and choroideremia. CONCLUSIONS: In this study we highlighted the presence of peculiar genotypic and phenotypic details in a family affected by syndromic X-linked hearing loss with intellectual disability. We identified two, previously unreported, Xq21.1-21.3 interstitial deletions. The two rearrangements, containing several genes, segregate with the clinical features, suggesting their role in the pathogenicity. However, not all the observed phenotypic features can be clearly associated with the known genes thus, further study is necessary to determine regions involved.