Clarin-2 gene supplementation durably preserves hearing in a model of progressive hearing loss.

Hearing loss is a major health concern affecting millions of people worldwide with currently limited treatment options. In clarin-2-deficient Clrn2-/- mice, used here as a model of progressive hearing loss, we report synaptic auditory abnormalities in addition to the previously demonstrated defects of hair bundle structure and mechanoelectrical transduction. We sought an in-depth evaluation of viral-mediated gene delivery as a therapy for these hearing-impaired mice. Supplementation with either the murine Clrn2 or human CLRN2 genes preserved normal hearing in treated Clrn2-/- mice. Conversely, mutated forms of CLRN2, identified in patients with post-lingual moderate to severe hearing loss, failed to prevent hearing loss. The ectopic expression of clarin-2 successfully prevented the loss of stereocilia, maintained normal mechanoelectrical transduction, preserved inner hair cell synaptic function, and ensured near-normal hearing thresholds over time. Maximal hearing preservation was observed when Clrn2 was delivered prior to the loss of transducing stereocilia. Our findings demonstrate that gene therapy is effective for the treatment of post-lingual hearing impairment and age-related deafness associated with CLRN2 patient mutations.

Novel Clinical Manifestation and Favorable Treatment Outcome of Cochlear Implant in a Chinese Family With Likely Pathogenic Variant of the P2RX2 Gene.

The rapid development and clinical application of sequencing technologies enable the genetic diagnosis of inherited deafness. P2RX2, as the gene responsible for autosomal dominant non-syndromic deafness-41 (DFNA41), has been proven to be essential for life-long normal hearing and for the protection of noise-induced hearing loss (NIHL). Our present study reports a missense variant in the P2RX2 gene (c.178G > T (p.V60L)), for the second time worldwide, in a five-generation kindred living in Henan, China. Despite carrying the same variant, the affected members in this family appear to present with earlier-onset hearing loss and poorer hearing compared to the original DFNA41 families. In addition, this study supplements some content that was not covered in previous reports. We quantitatively evaluated the pain perception ability of some members using the Pain Vision PS-2100 system, and further found an interesting clinical manifestation, that is, hyperalgesia, in heterozygotes for P2RX2 p.V60L. The cochlear implant (CI) was also provided for the proband of profound deafness, resulting in satisfactory clinical outcomes. Finally, we carried out a systematic review of recently published articles on the P2RX2 gene, which is beneficial for better understanding the role of the P2RX2 gene in the auditory system and the pathogenic mechanisms in sensorineural hearing loss (SNHL).

Late-onset, progressive sensorineural hearing loss in the paediatric population: a systematic review.

PURPOSE: To review possible risk factors for permanent delayed-onset, progressive sensorineural hearing loss (SNHL) in the paediatric population to recommend follow-up protocols for early detection. METHODS: PRISMA-compliant systematic review was performed, including observational studies on the paediatric population up to 16 years old who have passed the newborn hearing screening programme (NHSP), investigating the development of late-onset, progressive SNHL. Electronic searches were performed through Medline, Embase, Cochrane, and Emcare. RESULTS: 37 studies were included. 21 showed an association between late-onset SNHL and congenital cytomegalovirus (cCMV) infection (age at hearing loss diagnosis 0.75 to 204 months, mean 45.6 ± 43.9), while 16 between late-onset SNHL and other congenital or perinatal factors, namely Neonatal Intensive Care Unit (NICU) stay, prematurity, neonatal respiratory failure, mechanical ventilation, extracorporeal membrane oxygenation (ECMO) support, hypocapnia, hypoxia, alkalosis, seizure activity, congenital diaphragmatic hernia (CDH), inner ear malformation, and gene mutations (age at hearing loss diagnosis 2.5 to 156 months, mean 38.7 ± 40.7). CONCLUSIONS: cCMV infection may cause late-onset SNHL, which can be missed on standard NHSP. There is, therefore, evidence to support universal screening programmes to enable detection in even asymptomatic neonates. Ongoing audiological follow-up for all children with cCMV is advisable, to enable timely treatment. In the paediatric population presenting conditions such as NICU stay > 5 days, prematurity ≤ 34 weeks gestation, severe neonatal respiratory failure, mechanical ventilation, ECMO support, and CDH surgery, an audiological follow-up from 3 months of age up to at least 3-4 years of age, and at least annually, should be recommended.

Treatment following Triple-AAV Delivery in Mature Murine Model of Human CDH23-Associated Hearing Loss.

This study aimed to investigate the transduction efficiency of triple adeno-associated virus (AAV) vectors in the cochleae of adult mice, focusing on large-gene-associated hearing loss (HL). Additionally, we sought to evaluate the feasibility of cochlear gene therapy in a mouse model of human CDH23-mediated HL using the triple AAV approach. To create a reporter protein, we fused EGFP to mCherry, which was then divided into three parts, each packaged in a separate AAV2/2 vector. Four weeks after co-injecting the triple AAV vectors into 4-5-week-old mice, we assessed transduction efficiency. We found that up to 5.9% of inner hair cells were positive for both EGFP and mCherry. Subsequently, we developed triple Cdh23 AAV vectors for therapeutic purposes. After administering these vectors to 4- to 5-week-old C57/BL6 mice, we conducted auditory tests and immunohistochemistry studies over a period of 60 weeks. Co-injecting triple Cdh23-AAVs did not alter auditory function or lead to hair cell degeneration. In conclusion, this study confirms the feasibility of the triple-AAV approach for cochlear gene delivery. While this strategy did not produce any treatment effects, our findings suggest that large deafness genes could be potential future targets for cochlear gene therapy.

RotaRod and acoustic startle reflex performance of two potential mouse models for Meniere's disease.

Meniere's disease (MD) is a disorder of the inner ear characterized by chronic episodes of vertigo, tinnitus, increased aural pressure, and sensorineural hearing loss. Causes of MD are unknown, but endolymphatic hydrops is a hallmark. In addition, 5%-15% of MD cases have been identified as familial. Whole-genome sequencing studies of individuals with familial MD identified DTNA and FAM136A as candidate genes for autosomal dominant inheritance of MD. Although the exact roles of these genes in MD are unknown, FAM136A encodes a mitochondrial protein, and DTNA encodes a cytoskeletal protein involved in synapse formation and maintenance, important for maintaining the blood-brain barrier. It is also associated with a particular aquaporin. We tested vestibular and auditory function in dtna and fam136a knockout (KO) mice, using RotaRod and startle reflex-based clicker tests, respectively. Three-factor analysis of variance (ANOVA) results indicated that sex, age, and genotype were significantly correlated with reduced mean latencies to fall ("latencies") for male dtna KO mice, while only age was a significant factor for fam136a KO mice. Fam136a KO mice lost their hearing months before WTs (9-11 months vs. 15-20 months). In male dtna KO mice, divergence in mean latencies compared with other genotypes was first evident at 4 months of age, with older males having an even greater decrease. Our results indicate that fam136a gene mutations generate hearing problems, while dtna gene mutations produce balance deficits. Both mouse models should help to elucidate hearing loss and balance-related symptoms associated with MD.

Identification and characterisation of spontaneous mutations causing deafness from a targeted knockout programme.

BACKGROUND: Mice carrying targeted mutations are important for investigating gene function and the role of genes in disease, but off-target mutagenic effects associated with the processes of generating targeted alleles, for instance using Crispr, and culturing embryonic stem cells, offer opportunities for spontaneous mutations to arise. Identifying spontaneous mutations relies on the detection of phenotypes segregating independently of targeted alleles, and having a broad estimate of the level of mutations generated by intensive breeding programmes is difficult given that many phenotypes are easy to miss if not specifically looked for. Here we present data from a large, targeted knockout programme in which mice were analysed through a phenotyping pipeline. Such spontaneous mutations segregating within mutant lines may confound phenotypic analyses, highlighting the importance of record-keeping and maintaining correct pedigrees. RESULTS: Twenty-five lines out of 1311 displayed different deafness phenotypes that did not segregate with the targeted allele. We observed a variety of phenotypes by Auditory Brainstem Response (ABR) and behavioural assessment and isolated eight lines showing early-onset severe progressive hearing loss, later-onset progressive hearing loss, low frequency hearing loss, or complete deafness, with vestibular dysfunction. The causative mutations identified include deletions, insertions, and point mutations, some of which involve new genes not previously associated with deafness while others are new alleles of genes known to underlie hearing loss. Two of the latter show a phenotype much reduced in severity compared to other mutant alleles of the same gene. We investigated the ES cells from which these lines were derived and determined that only one of the 8 mutations could have arisen in the ES cell, and in that case, only after targeting. Instead, most of the non-segregating mutations appear to have occurred during breeding of mutant mice. In one case, the mutation arose within the wildtype colony used for expanding mutant lines. CONCLUSIONS: Our data show that spontaneous mutations with observable effects on phenotype are a common side effect of intensive breeding programmes, including those underlying targeted mutation programmes. Such spontaneous mutations segregating within mutant lines may confound phenotypic analyses, highlighting the importance of record-keeping and maintaining correct pedigrees.

Long-term follow-up of children with hearing loss that is minimally progressive.

OBJECTIVES: The purpose of this study was to describe changes in audiometric thresholds over time in children whose hearing loss demonstrated early mild progression. DESIGN: This was a retrospective follow-up study to examine long-term audiologic results in children with progressive loss. STUDY SAMPLE: We examined audiologic data for 69 children, (diagnosed from 2003 to 2013), who had been previously categorised as having "minimal" progressive hearing loss. RESULTS: Children had a median of 10.0 (7.5, 12.1) years of follow-up and a median age of 12.5 (IQR: 11.0, 14.5) years; 92.8%; 64 of 69) of children continued to show progressive hearing loss (defined as a decrease of ≥10 dB at two or more adjacent frequencies between 0.5 and 4 kHz or a decrease in 15 dB at one frequency) in at least one ear since diagnosis. Further examination showed that 82.8% of ears (106 of 128) had deterioration in hearing. Of the 64 children, 29.7% (19/64) showed further deterioration since the first analysis. CONCLUSION: More than 90% of children identified as having minimal progressive hearing loss continued to show deterioration in hearing. Ongoing audiological monitoring of children with hearing loss is indicated to ensure timely intervention and to better counsel families.

SCN11A gene deletion causes sensorineural hearing loss by impairing the ribbon synapses and auditory nerves.

BACKGROUND: The SCN11A gene, encoded Nav1.9 TTX resistant sodium channels, is a main effector in peripheral inflammation related pain in nociceptive neurons. The role of SCN11A gene in the auditory system has not been well characterized. We therefore examined the expression of SCN11A in the murine cochlea, the morphological and physiological features of Nav1.9 knockout (KO) ICR mice. RESULTS: Nav1.9 expression was found in the primary afferent endings beneath the inner hair cells (IHCs). The relative quantitative expression of Nav1.9 mRNA in modiolus of wild-type (WT) mice remains unchanged from P0 to P60. The number of presynaptic CtBP2 puncta in Nav1.9 KO mice was significantly lower than WT. In addition, the number of SGNs in Nav1.9 KO mice was also less than WT in the basal turn, but not in the apical and middle turns. There was no lesion in the somas and stereocilia of hair cells in Nav1.9 KO mice. Furthermore, Nav1.9 KO mice showed higher and progressive elevated ABR threshold at 16 kHz, and a significant increase in CAP thresholds. CONCLUSIONS: These data suggest a role of Nav1.9 in regulating the function of ribbon synapses and the auditory nerves. The impairment induced by Nav1.9 gene deletion mimics the characters of cochlear synaptopathy.

Generation and pathological characterization of a transgenic mouse model carrying a missense PJVK mutation.

Hearing loss is the most prevalent hereditary sensory disorder in children. Approximately 2 in 1000 infants are affected by genetic hearing loss. The PJVK gene, which encodes the pejvakin protein, has been linked to autosomal recessive non-syndromic hearing loss DFNB59. Previous clinical studies have revealed that PJVK mutations might be associated with a wide spectrum of auditory manifestations, ranging from hearing loss of pure cochlear origin to that involving the retrocochlear central auditory pathway. The phenotypic variety makes the pathogenesis of this disease difficult to determine. Similarly, mouse models carrying different Pjvk defects show phenotypic variability and inconsistency. In this study, we generated a knockin mouse model carrying the c.874G > A (p.G292R) variant to model and investigate the auditory and vestibular phenotypes of DFNB59.

The BEACH protein LRBA is required for hair bundle maintenance in cochlear hair cells and for hearing.

Lipopolysaccharide-responsive beige-like anchor protein (LRBA) belongs to the enigmatic class of BEACH domain-containing proteins, which have been attributed various cellular functions, typically involving intracellular protein and membrane transport processes. Here, we show that LRBA deficiency in mice leads to progressive sensorineural hearing loss. In LRBA knockout mice, inner and outer hair cell stereociliary bundles initially develop normally, but then partially degenerate during the second postnatal week. LRBA deficiency is associated with a reduced abundance of radixin and Nherf2, two adaptor proteins, which are important for the mechanical stability of the basal taper region of stereocilia. Our data suggest that due to the loss of structural integrity of the central parts of the hair bundle, the hair cell receptor potential is reduced, resulting in a loss of cochlear sensitivity and functional loss of the fraction of spiral ganglion neurons with low spontaneous firing rates. Clinical data obtained from two human patients with protein-truncating nonsense or frameshift mutations suggest that LRBA deficiency may likewise cause syndromic sensorineural hearing impairment in humans, albeit less severe than in our mouse model.

LittlEARS auditory questionnaire as an infant hearing screening in Germany after the newborn hearing screening.

Objective: To investigate the feasibility of using the LittlEARS® Auditory Questionnaire (LEAQ®) as part of the infant hearing screening programme in Germany. Design: LEAQ®s were distributed to 47 paediatric practices and were completed by the parents/guardians of the infants (aged between 9-14 months) involved in the study (= LEAQ® screening). The infants who failed the LEAQ® screening were invited to a LEAQ rescreening. Infants who failed the LEAQ® rescreening were sent to a paediatric ENT specialist. After 3 years, a follow-up was performed on two groups: the first group comprised infants who failed the LEAQ screening; the second group (control group) comprised 200 infants who passed the LEAQ screening. Study Sample: 5316 questionnaires were returned. Results: Six infants with permanent hearing loss were identified using the LEAQ® as a screening tool. Conclusions: An infant hearing screening using the LEAQ® is easily implementable in paediatric practices and may be a good alternative in countries where no objective screening instruments are available. The LEAQ® was suitable for monitoring hearing development in infants in general and could help to identify a late-onset or progressive hearing loss in infants.

Otoprotective effects of mouse nerve growth factor in DBA/2J mice with early-onset progressive hearing loss.

As it displays progressive hair-cell loss and degeneration of spiral ganglion neurons (SGNs) characterized by early-onset progressive hearing loss (ePHL), DBA/2J is an inbred mouse strain widely used in hearing research. Mouse nerve growth factor (mNGF), as a common exogenous nerve growth factor (NGF), has been studied extensively for its ability to promote neuronal survival and growth. To determine whether mNGF can ameliorate progressive hearing loss (PHL) in DBA/2J mice, saline or mNGF was given to DBA/2J mice of either sex by daily intramuscular injection from the 1st to the 9th week after birth. At 5, 7, and 9 weeks of age, in comparison with vehicle groups, mNGF groups experienced decreased auditory-evoked brainstem response (ABR) thresholds and increased distortion product otoacoustic emission (DPOAE) amplitudes, the prevention of hair cell loss, and the inhibition of apoptosis of SGNs. Downregulation of Bak/Bax and Caspase genes and proteins in cochleae of mice receiving the mNGF treatment was detected by real-time PCR, Western blot, and immunohistochemistry. This suggests that the Bak-dependent mitochondrial apoptosis pathway may be involved in the otoprotective mechanism of mNGF in progressive hearing loss of DBA/2J mice. Our results demonstrate that mNGF can act as an otoprotectant in the DBA/2J mice for the early intervention of PHL and, thus, could become of great value in clinical applications. © 2017 Wiley Periodicals, Inc.

Progressive macrothrombocytopenia and hearing loss in a large family with DIAPH1 related disease.

In this study, we describe a Japanese family with progressive hearing loss and macrothrombocytopenia. Using next-generation and Sanger sequencing analyses, we identified a heterozygous variant in exon 27 of the DIAPH1 gene (NM_005219), c.3637C>T, p.R1213X. All patients in the family had sensorineural hearing loss and macrothrombocytopenia. None of the patients exhibited a tendency to bleed. No pathogenic variants were found in the MYH9 gene. Hearing loss began with high-frequency loss during early childhood and progressed to severe hearing loss involving all frequencies. Analyses of the mean platelet volume and platelet distribution width indicated that the macrothrombocytopenia is progressive in patients with DIAPH1 related disease.There are no reports describing progressive macrothrombocytopenia in patients with pathogenic variants of DIAPH1. Thus, progressive macrothrombocytopenia may be a novel feature of deafness patients with pathogenic variants in DIAPH1.

AUNA2: A Novel Type of Non-Syndromic Slowly Progressive Auditory Synaptopathy/Auditory Neuropathy with Autosomal-Dominant Inheritance.

BACKGROUND: Auditory synaptopathy/neuropathy (AS/AN) is a heterogeneous disorder, which may be caused by environmental factors like postnatal hyperbilirubinemia or by genetic factors. The genetic forms are subdivided into syndromic and non-syndromic types, and show different inheritance patterns with a strong preponderance of autosomal-recessive forms. To date, only a single locus for non-syndromic autosomal-dominant AS/AN (AUNA1) has been reported in a single family, in which a non-coding DIAPH3 mutation was subsequently described as causative. MATERIALS AND METHODS: Here, we report detailed clinical data on a large German AS/AN family with slowly progressive postlingual hearing loss. Affected family members developed their first symptoms in their second decade. Moderate hearing loss in the fourth decade then progressed to profound hearing impairment in older family members. Comprehensive audiological and neurological tests were performed in the affected family members. Genetic testing comprised linkage analyses with polymorphic markers and a genome-wide linkage analysis using the Affymetrix GeneChip® Human Mapping 250K. RESULTS AND CONCLUSION: We identified a large family with autosomal-dominant AS/AN. By means of linkage analyses, the AUNA1 locus was excluded, and putatively linked regions on chromosomal bands 12q24 and 13q34 were identified as likely carrying the second locus for autosomal-dominant AS/AN (AUNA2). AUNA2 is associated with a slowly progressive postlingual hearing loss without any evidence for additional symptoms in other organ systems.

Detailed hearing and vestibular profiles in the patients with COCH mutations.

OBJECTIVES: To evaluate the clinical features of Japanese DFNA9 families with mutations of the COCH gene. METHODS: Mutation screening was performed using targeted next-generation sequencing (NGS) for 63 previously reported deafness genes. The progression of hearing loss and vestibular dysfunction were evaluated by pure-tone audiometry, caloric testing, cVEMP, and computed dynamic posturography. RESULTS: We detected 1 reported mutation of p.G88E and 2 novel mutations of p.I372T and p.C542R. The patients with the novel mutations of p.I372T and p.C542R within the vWFA2 domain showed early onset progressive hearing loss, and the patients with the p.G88E mutation showed late onset hearing loss and acute hearing deterioration over a short period. Vestibular symptoms were reported in the patients with p.G88E and p.C542R. Vestibular testing was performed for the family with the p.G88E mutation. Severe vestibular dysfunction was observed in the proband, and the proband's son showed unilateral semicircular canal dysfunction with mild hearing loss. CONCLUSIONS: Targeted exon resequencing of selected genes using NGS successfully identified mutations in the relatively rare deafness gene, COCH, in the Japanese population. The phenotype is compatible with that described in previous reports. Additional supporting evidence concerning progressive hearing loss and deterioration of vestibular function was obtained from our study.

Incidence of platinum-induced ototoxicity in pediatric patients in Quebec.

BACKGROUND: The antineoplastic agents cisplatin and carboplatin are widely-used and highly-effective against a variety of pediatric cancers. Unfortunately, ototoxicity is a frequently encountered side effect of platinum-based chemotherapy. There is currently no treatment or prevention for platinum-induced ototoxicity and development of hearing loss may lead to devastating consequences on the quality of life of pediatric cancer survivors. The objective of this study is to determine the incidence of platinum-induced ototoxicity in a large series of pediatric patients and to evaluate the incidence of progression of ototoxicity after completion of treatment. PROCEDURES: A retrospective chart review of pediatric patients treated with cisplatin or carboplatin between 2000 and 2012 was conducted. The incidence of ototoxicity was determined based on the American-Speech-Language-Hearing Association (ASHA) criteria and severity was based on the Chang classification. RESULTS: Four hundred and sixty-six patients received platinum-based chemotherapy. Patients were excluded due to congenital hearing loss (n = 1) and insufficient data for calculating the platinum dose (n = 24) or for assessing ototoxicity (n = 135). Three hundred and six patients were included in the analysis. Post-chemotherapy ototoxicity was detected in 148 (48%) patients, and clinically-significant ototoxicity was present in 91 (30%). In addition, based on the ASHA criteria, 48% of patients (97/204) with long-term follow-up had further deterioration of their hearing after completion of treatment. CONCLUSIONS: Ototoxicity following chemotherapy with cisplatin or carboplatin is common and can frequently progress after the completion of treatment. Long-term follow-up is strongly recommended.

Unusual phenotype in 35delG mutation: a case report.

BACKGROUND: Mutations in the GJB2 gene, which encodes the protein connexin 26 and is involved in inner ear homeostasis, are identified in approximately 50% of patients with autosomal recessive nonsyndromic hearing loss, making it one of the primary causes of prelingual nonsyndromic hearing loss in various populations. The 35delG mutation, one of the most common mutations of the GJB2 gene, usually causes prelingual, bilateral mild to profound, nonprogressive sensorineural hearing loss. CASE PRESENTATION: We present an unusual case of an 18-year-old Turkish female with heterozygous 35delG mutation and postlingual, profound-sloping, progressive and fluctuating unilateral sensorineural hearing loss. The phenotype is different from the usual findings. CONCLUSIONS: The 35delG mutation causing hearing loss may not always be reflected in the phenotype as expected and therefore may have different audiologic manifestations.

A new mutation of Sgms1 causes gradual hearing loss associated with a reduced endocochlear potential.

Sgms1 encodes sphingomyelin synthase 1, an enzyme in the sphingosine-1-phosphate signalling pathway, and was previously reported to underlie hearing impairment in the mouse. A new mouse allele, Sgms1tm1a, unexpectedly showed normal Auditory Brainstem Response thresholds. We found that the Sgms1tm1a mutation led to incomplete knockdown of transcript to 20 % of normal values, which was enough to support normal hearing. The Sgms1tm1b allele was generated by knocking out exon 7, leading to a complete lack of detectable transcript in the inner ear. Sgms1tm1b homozygotes showed largely normal auditory brainstem response thresholds at first, followed by progressive loss of sensitivity until they showed severe impairment at 6 months old. The endocochlear potential was consistently reduced in Sgms1tm1b mutants at 3, 4 and 8 weeks old, to around 80 mV compared with around 120 mV in control littermates. The stria vascularis showed a characteristic irregularity of marginal cell surfaces and patchy loss of Kcnq1 expression at their apical membrane, and expression analysis of the lateral wall suggested that marginal cells were the most likely initial site of dysfunction in the mutants. Finally, significant association of auditory thresholds with DNA markers within and close to the human SGMS1 gene were found in the 1958 Birth Cohort, suggesting that SGMS1 variants may play a role in the range of hearing abilities in the human population.

Superficial Siderosis: A Case Report of Underdiagnosed Disorder.

Superficial siderosis (SS) is caused by subpial hemosiderin deposition due to chronic low-grade bleeding into the subarachnoid space. Dural tears are the most common etiology. Slowly progressive gait ataxia and hearing impairment are common clinical manifestations. Brain magnetic resonance imaging (MRI) shows linear superficial hypointensity on the T2 weighted images and gradient echo. The therapeutic approach is surgical repair of the bleeding source. The patient presented with progressive hearing loss and ataxia. Neurological examination revealed bilateral hearing loss, nystagmus, dysarthria, brisk deep tendon reflexes, and severe ataxia. Brain MRI showed linear superficial siderosis in the cerebrum, cerebellum, and brain stem. Spinal MRI showed ventral epidural cerebrospinal fluid (CSF) collection and disc-osteophyte complex. Six months after the surgical repair of the dural defect, the patient's neurological examination demonstrated improvement in ataxia and dysarthria. The patient was able to walk without any assistance. Surgical repair of the underlying bleeding source may be beneficial in preventing the progression and improving the symptoms of superficial siderosis SS. This case suggests that SS symptoms are potentially reversible by surgical treatment of the underlying spinal CSF leak after a long disease course.

Comprehensive Genetic Evaluation in Patients with Special Reference to Late-Onset Sensorineural Hearing Loss.

Hearing loss (HL) is a common and multi-complex etiological deficit that can occur at any age and can be caused by genetic variants, aging, toxic drugs, noise, injury, viral infection, and other factors. Recently, a high incidence of genetic etiologies in congenital HL has been reported, and the usefulness of genetic testing has been widely accepted in congenital-onset or early-onset HL. In contrast, there have been few comprehensive reports on the relationship between late-onset HL and genetic causes. In this study, we performed next-generation sequencing analysis for 91 HL patients mainly consisting of late-onset HL patients. As a result, we identified 23 possibly disease-causing variants from 29 probands, affording a diagnostic rate for this study of 31.9%. The highest diagnostic rate was observed in the congenital/early-onset group (42.9%), followed by the juvenile/young adult-onset group (31.7%), and the middle-aged/aged-onset group (21.4%). The diagnostic ratio decreased with age; however, genetic etiologies were involved to a considerable degree even in late-onset HL. In particular, the responsible gene variants were found in 19 (55.9%) of 34 patients with a familial history and progressive HL. Therefore, this phenotype is considered to be a good candidate for genetic evaluation based on this diagnostic panel.