Exogenous neuritin restores auditory following cochlear spiral ganglion neuron denervation of gerbils

Spiral ganglion neurons (SGNs) transmit sound signals received by hair cells to the auditory center to produce hearing. The quantity and function are important for maintaining normal hearing function. Limited by the regenerative capacity, SGNs are unable to regenerate spontaneously after injury. Various neurotrophic factors play an important role in the regeneration process. Neuritin is a neurite growth factor that plays an important role in neural plasticity and nerve injury repair. In this study, we used bioinformatics analysis to show that neuritin was negatively correlated with cochlear damage. Then, we aimed to establish a cochlear spiral ganglion-specific sensorineural deafness model in gerbils using ouabain and determine the effects of exogenous neuritin protein in protecting damaged cochlear SGNs and repairing damaged auditory nerve function. The provides a new research strategy and scientific basis for the prevention and treatment of sensorineural deafness caused by the loss of SGNs. We were discovered that neuritin is expressed throughout the development of the gerbil cochlea, primarily in the SGNs and Corti regions. The expression of neuritin was negatively correlated with the sensorineural deafness induced by ouabain. In vitro and in vivo revealed that neuritin significantly maintained the number and arrangement of SGNs and nerve fibers in the damaged cochlea and effectively protected the high-frequency listening function of gerbils.

Atypical presentation of subclavian steal syndrome with left sided sensorineural deafness

We present a rare manifestation of a common pathology: left sided sensorineural hearing loss secondary to subclavian steal syndrome after thoracic endovascular aortic repair for complicated acute aortic dissection. We describe the vascular physiology that can result in unilateral hearing loss and provide a brief review of subclavian steal syndrome. This case report highlights the importance of avid clinical recognition of an atypical presentation of a common vascular disease.

An Italian case series' description of thiamine responsive megaloblastic anemia syndrome: importance of early diagnosis and treatment

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.

Association between neuroimaging findings and neurological sequelae in patients with congenital cytomegalovirus infection

BACKGROUND

Congenital cytomegalovirus (CMV) infection is an important cause of disability. There is little evidence on the prognostic value of lesions identified in neuroimaging studies.

AIM

The study aimed to assess the severity of lesions detected with brain MRI and transfontanellar ultrasound and their relationship with long-term neurological deficits.

PATIENTS AND METHODS

We performed a retrospective, analytical, observational study of 36 patients with congenital CMV infection. Neuroimaging studies were reviewed and classified according to the modified Noyola' scale. Imaging findings were compared with neurological alterations in the patients' most recent follow-up evaluation at the paediatric neurology department.

RESULTS

Thirty-six patients were studied (transfontanellar ultrasound: 30; brain MRI: 29). Twenty of 30 patients showed ultrasound abnormalities; of these, 11 showed alterations on brain MR images (P=.04) and 10 had neurological impairment (P=.008). Transfontanellar ultrasound had a sensitivity of 83.3%, 90% CI: 58-100 and a specificity of 44.4%, 90% CI: 18.7-70.2 for predicting neurological sequelae. Brain MRI displayed abnormalities in 20 of 29 patients, of whom 16 had neurological impairment (P<.001). MRI had a sensitivity of 94%, 95% CI: 80-100 and a specificity of 66.6%, 95% CI: 36-97.5 for predicting neurological sequelae. Modified Noyola' scale values >2 were correlated with psychomotor retardation (P<.001).

CONCLUSIONS

Our findings validate previous studies reporting a statistical significant correlation between the extension of neuroimaging lesions and severity of neurological deficits.

Reticular dysgenesis exacerbated by hemophagocytic lymphohistiocytosis and the presence of unusual histiocyte-like cells in bone marrow

We report a rare case of agranulocytosis and lymphopenia complicated with hemophagocytic lymphohistiocytosis. Diagnosis of reticular dysgenesis was made by detection of a pathogenic stop gain variant in the AK2 gene on targeted next generation sequencing and confirmed by Sanger sequencing. Parents were found to be carriers for this variant. Bone marrow aspirate and biopsy was also performed with a clinical diagnosis of severe combined immunodeficiency with HLH. However, no hemophagocytosis was noted in the bone marrow aspirate or trephine biopsy. Instead, it showed aggregates of large histiocyte-like cells, scattered erythroid precursors and megakaryocytes. These cells were confused to be some form of storage cells, but did not resemble storage cells seen in Gaucher's disease or Niemann Pick disease. Myeloid precursors were very few in number. Reticular dysgenesis was not suspected during admission due to a lack of awareness of this entity. Testing for sensorineural deafness in neonates with severe agranulocytosis and lymphopenia would facilitate an early diagnosis of reticular dysgenesis. To the best of our knowledge, hemophagocytic lymphohistiocytosis has not been previously reported in association with reticular dysgenesis.

Association between neuroimaging findings and neurological sequelae in patients with congenital cytomegalovirus infection

BACKGROUND

Congenital cytomegalovirus (CMV) infection is an important cause of disability. There is little evidence on the prognostic value of lesions identified in neuroimaging studies.

AIM

The study aimed to assess the severity of lesions detected with brain MRI and transfontanellar ultrasound and their relationship with long-term neurological deficits.

PATIENTS AND METHODS

We performed a retrospective, analytical, observational study of 36 patients with congenital CMV infection. Neuroimaging studies were reviewed and classified according to the modified Noyola' scale. Imaging findings were compared with neurological alterations in the patients' most recent follow-up evaluation at the paediatric neurology department.

RESULTS

Thirty-six patients were studied (transfontanellar ultrasound: 30; brain MRI: 29). Twenty of 30 patients showed ultrasound abnormalities; of these, 11 showed alterations on brain MR images (P = .04) and 10 had neurological impairment (P = .008). Transfontanellar ultrasound had a sensitivity of 83.3%, 90% CI: 58-100 and a specificity of 44.4%, 90% CI: 18.7-70.2 for predicting neurological sequelae. Brain MRI displayed abnormalities in 20 of 29 patients, of whom 16 had neurological impairment (P < .001). MRI had a sensitivity of 94%, 95% CI: 80-100 and a specificity of 66.6%, 95% CI: 36-97.5 for predicting neurological sequelae. Modified Noyola' scale values > 2 were correlated with psychomotor retardation (P < .001).

CONCLUSIONS

Our findings validate previous studies reporting a statistical significant correlation between the extension of neuroimaging lesions and severity of neurological deficits.

Reversible splenial lesion syndrome in sisters with sensorineural deafness as the first manifestation

Reversible splenial lesion syndrome (RESLES) is a rare clinico-radiological disorder syndrome with unclear pathophysiology. Here, two sisters with sensorineural deafness as the chief complaint diagnosed with RESLES was reported. Although the sisters had the disease successively, they were divided into two types on imaging by isolated lesions of splenium of the corpus callosum (SCC) and extensive lesions of the corpus callosum. The clinical manifestations and lesions on MRI disappeared after 6 months. The sensorineural deafness of the sisters in this article may be caused by transcallosal auditory pathway (TCAP) injury. Auditory handicap has been found in previous RESLES cases, indicating that we know little about the connection between the SCC and the auditory pathway, and further research is needed.

Idiopathic superficial siderosis of the central nervous system

Background

Regardless of the cause of the superficial siderosis (SS) disease, which is bleeding, the source of bleeding cannot be found in some cases.

Case presentation

In this article, we report two cases with idiopathic SS. Case 1 presented with bilateral hearing loss, cognitive impairment, sleep disturbances, and tremors. Case 2 presented with sensory neural hearing loss, ataxia, and spastic paraparesis. In both cases, brain MRI indicated evidence of SS. CT myelogram and SPECT with labeled RBC couldn’t help finding the source of occult bleeding.

Conclusion

SS is a rare central nervous system disease caused by the deposition of hemosiderin in the brain and spinal cord, which results in the progression of neurological deficits. The cause of this hemorrhage is often subarachnoid haemorrhage, intracranial surgery, carcinoma, arteriovenous malformation, nerve root avulsion, and dural abnormality. The condition progresses slowly and, by the time diagnosis is confirmed, the damage is often irreversible. In our cases, brain MRI clarified the definitive diagnosis, but we could not find the source of bleeding. SS should be considered in cases with ataxia and hearing loss, even if no source of bleeding is found.

Novel mutations of SOX10 gene in Chinese patients with type II Waardenburg syndrome

Waardenburg Syndrome (WS) is a condition characterized by sensorineural deafness and pigment disturbances of the skin, hair and iris. By using the latest genomics technology, the WS-related gene mutations and corresponding mechanisms have been widely studied and reported. and the high genetic heterogeneity of the disease has also been explained. However, the SOX10 gene transcription and expression has still be unclear. In this study, we determined the phenotypic gene expression of WS patients in two Chinese WS families. More importantly, we identified two novel SOX10 mutations, c.482-487del (p.R161-M162del)and c.52G > T (p.E18X) in WSII for the first time in the Chinese population.

The French Cochlear Implant Registry (EPIIC): Cochlear implant candidacy assessment of off-label indications

OBJECTIVE

Evaluate in France the outcomes of cochlear implantation outside the selection criteria, off-label.

MATERIAL AND METHODS

This is a prospective cohort study including adults and children having received a cochlear implant (CI) in an off-label indication, that is outside the criteria established by the "Haute Autorité de santé (HAS)" in 2012. The data was collected from the "EPIIC" registry on recipients who received CIs in France between 2011 and 2014. Speech audiometry was performed at 60dB preimplantation and after one year of CI use, as well as an evaluation of the scores of the quality of life with the APHAB questionnaire, the scores for CAP and the professional/academic status in pre- and post-implantation conditions. Major and minor complications at surgery have been recorded.

RESULTS

In total, 590 patients (447 adults and 143 children) with an off-label indication for CIs were included in this study from the EPIIC registry (11.7% of the whole cohort of EPIIC). For adults, the median percentage of comprehension using monosyllabic word lists was 41% in preimplantation condition versus 53% after one year of CI use (P<0.001) and 60% versus 71% in dissyllabic word lists (P<0.001). The CAP scores were 5 versus 6 in pre- and post-implantation conditions respectively (P<0.001) and the APHAB scores were statistically lower after implantation (P<0.001). In the children cohort, the median percentage of comprehension using monosyllabic word lists was 51% in preimplantation condition and 65% after CI (P<0.001), and 48% versus 82% (P<0.001) for dissyllabic word lists. The CAP scores were 5 versus 7 respectively in pre- and post-CI conditions (P<0.001). Thirty-two minor complications (5.4%) and 17 major complications (2.8%) were reported in our panel of off-label indication patients.

CONCLUSION

These results suggest that a revision of the cochlear implantation candidacy criteria is necessary to allow more patients with severe or asymmetric hearing loss to benefit from a CI when there is an impact on quality of life despite the use of an optimal hearing aid.

Role of Platelet Rich Plasma in Tympanoplasty

To compare the efficacy of platelet rich plasma (PRP) in Tympanoplasty. Comparative study of Tympanoplasty with and without PRP. A total of 82 patients having dry large central perforation underwent type I Tympanoplasty by transcanal route under local anesthesia. Control group underwent surgery without PRP. The study group Tympanoplasty was added with PRP by PRP soaked gel foam placed in middle ear, over the graft and in bony canal along with wetting the temporal fascia by PRP graft. Preoperative and post operative audiometry was done. Result compared. Majority of the patients were of the age group of 20-30 years. Success rate of graft uptake was 85.3% in control group and 95.1% in PRP group. Hearing Improvements in control group was 46.3% and in PRP group was 78.0%. This study confirms addition of PRP in Tympanoplasty enhances the success rate in graft uptake early healing with improvement in hearing.

Hypoparathyroidism, Sensorineural deafness and renal disease (Barakat syndrome) caused by a reduced gene dosage in GATA3: a case report and review of literature

BACKGROUND

Barakat syndrome is an autosomal dominant rare genetic disease caused by haploinsufficiency of the GATA binding protein 3 (GATA3) gene. It is also known as HDR syndrome, and is characterized by varying degrees of hypoparathyroidism, sensorineural deafness and renal disease. This is the first report of a heterozygous GATA3 whole gene deletion causing HDR syndrome in a Sri Lankan family.

CASE PRESENTATION

A 13-year-old boy with an acute febrile illness, hypocalcaemia and bilateral carpopedal spasm was referred for evaluation. A past medical history of treatment for persistent hypocalcaemic symptoms since the age of 7 months was obtained. Biochemical investigations showed persistent low serum corrected calcium levels with hyperphosphataemia, hypomagnesaemia, low parathyroid hormone levels, hypercalciuria, and low total 25-hydroxy vitamin D levels. His renal functions and renal sonography were normal. Audiometry showed bilateral moderate to severe sensorineural hearing loss. On screening, his mother was also found to have asymptomatic hypocalcaemia, hypomagnesaemia, hyperphosphataemia, hypercalciuria and low total 25-hydroxy vitamin D levels. She had impaired renal functions and chronic parenchymal changes in the renal scan. Audiometry showed bilateral profound sensorineural hearing loss. Genetic analysis using multiplex-ligation dependent probe amplification showed a reduced gene dosage for GATA3 that is consistent with a heterozygous whole gene deletion in both the child and mother.

CONCLUSIONS

This report demonstrates the wide intra-familial phenotypic variability observed in HDR syndrome and adds further to the existing scientific literature on the genotype-phenotype correlation of this syndrome. It highlights the need for HDR syndrome to be considered in the differential diagnosis of persistent hypocalcaemia with sensorineural deafness and/or renal involvement, and for appropriate genetic evaluation to be done to confirm the diagnosis.

Novel EYA4 variant in Slovak family with late onset autosomal dominant hearing loss: a case report

Background

Progressive bilateral sensorineural deafness in postlingual period may be linked to many different etiologies including genetic factors. Identification of the exact deafness cause may, therefore, be quite challenging. Here we present a family with late-onset hearing loss as an autosomal dominant trait caused by a novel EYA4 mutation.

Case presentation

Forty-four years old female proband clinically investigated for progressive hearing loss and occasional dizziness with positive family history for deafness was subject to molecular-genetic testing. Patient’s DNA sample was analyzed by whole exome sequencing. We identified a novel missense variant c.804G > C located at the last base pair of exon 10 in EYA4. Candidate variant was confirmed by Sanger sequencing in the proband and her family members. In silico prediction tools and co-segregation analysis were used to indicate pathogenicity of the identified variant. To confirm our hypothesis, we performed minigene assay to demonstrate if the transcript of exon 10 in EYA4 is present. We provide evidence that this mutation in vitro compromises donor site functionality and causes exon 10 skipping and frameshift that most likely results in nonsense-mediated mRNA decay. The onset of moderate to severe hearing loss in the family ranged from 10 to 40 years. The normal cardiac phenotype was confirmed by ECG and echocardiography.

Conclusions

We identified a novel EYA4 mutation associated with adult-onset autosomal dominant sensorineural hearing loss. This report extends the knowledge of spectrum of EYA4 mutations and demonstrates the pathogenicity of a variant affecting specific position in the gene. A comprehensive review of known EYA4 mutations is also given and their impact on cardiac phenotype is discussed. Our findings highlight the importance of genetic testing and complex clinical assessment in patients with familial progressive hearing loss.

Primary coenzyme Q10 Deficiency-6 (COQ10D6): Two siblings with variable expressivity of the renal phenotype

Primary coenzyme Q10 deficiency-6 (COQ10D6) is a rare autosomal recessive disorder caused by COQ6 mutations. The main clinical manifestations are infantile progressive nephrotic syndrome (NS) leading to end-stage renal disease and sensorineural deafness. A 7-year-old girl was diagnosed with steroid-resistant NS (SRNS) and an audiological work-up revealed bilateral sensorineural deafness. A renal biopsy demonstrated focal segmental glomerulosclerosis. Despite immunosuppressive therapy, her serum levels of creatinine increased and haemodialysis was indicated within 1 year after the diagnosis. Living-donor kidney transplantation was performed in the eighth month of haemodialysis. A diagnostic custom-designed panel-gene test including 30 genes for NS revealed homozygous c.1058C > A [rs397514479] in exon nine of COQ6. Her older brother, who had sensorineural hearing loss with no renal or neurological involvement, had the same mutation in homozygous form. COQ6 mutations should be considered not only in patients with SRNS with sensorineural hearing loss but also in patients with isolated sensorineural hearing loss with a family history of NS. The reported p.His174 variant of COQ8B was suggested to be a risk factor for secondary CoQ deficiency, while p.Arg174 appeared to improve the condition in a yeast model. Family segregation and the co-occurrence of biallelic p.Arg174 of COQ8B in a brother with hearing loss implied that the interaction of the altered COQ8B with the mutant COQ6 alleviated the symptoms in this family. CoQ10 replacement therapy should be initiated for these patients, as primary CoQ10 deficiency is considered the only known treatable mitochondrial disease.

Natural history and clinical characteristics of 50 patients with Wolfram syndrome

PURPOSE

To describe clinical characteristics of diabetes mellitus (DM) in a group of patients with Wolfram Syndrome (WS).

METHODS

Descriptive, cross-sectional observational design. The sample consisted of 50 patients diagnosed with WS. Clinical criteria contributing to WS diagnosis were analyzed: diabetes mellitus (DM), optic nerve atrophy (OA), sensorineural deafness, urological and neurological dysfunction, among others. These parameters were assessed according to their presence/absence, age of onset, and various clinical-analytical parameters.

RESULTS

All the patients studied presented DM and OA, with a mean age of onset of 5.4 ± .9 (1-14) years and 9 ± .9 (1-16) years, respectively. The remaining criteria were present with a variable frequency: 77% had diabetes insipidus, 66.7% auditory alterations, 77.8% neurogenic bladder, 61.1% neurological involvement, and 27.8% hypogonadism. A 16.7% of the patients had positive albuminuria (urinary albumin/creatinine ratio > 30 mg/g) and 72.2% had hyporreflexia. There were no significant differences in the age of diagnosis nor of the presence of different pathologies according to sex.

CONCLUSIONS

The early presence of a non-autoimmune insulin dependent DM, should alert us of an "infrequent" diabetes syndrome. Wolfram's presumptive diagnosis could be established if juvenile-onset DM occurs concomitantly with OA, and this visual impairment is not attributable to diabetic retinopathy. Despite the long period of evolution of DM and altered values of HbA1c, the prevalence of microvascular complications in the sample are low.

The first successful application of preimplantation genetic diagnosis for hearing loss in Iran

Hearing impairment (HI) caused by mutations in the connexin-26 gene (GJB2) accounts for the majority of cases with inherited, nonsyndromic sensorineural hearing loss. Due to the illegality of the abortion of deaf fetuses in Islamic countries, preimplantation genetic diagnosis (PGD) is a possible solution for afflicted families to have a healthy offspring. This study describes the first use of PGD for GJB2 associated non-syndromic deafness in Iran. GJB2 donor splicing site IVS1+1G&gt;A mutation analysis was performed using Sanger sequencing for a total of 71 Iranian families with at least 1 deaf child diagnosed with non-syndromic deafness. In Vitro Fertilization (IVF) was performed, followed by PGD for a cousin couple with a 50% chance of having an affected child. Bi-allelic pathogenic mutations were found in a total of 12 families (~17 %); of which a couple was a PGD volunteer. The deaf woman in this family was homozygous and her husband was a carrier of the IVS1+1G&gt;A gene mutation. Among 8 biopsied embryos, two healthy embryos were implanted which resulted in a single pregnancy and subsequent birth of a healthy baby boy. This is the first report of a successful application of PGD for hearing loss in Iran. Having a baby with a severe hearing impairment often imposes families with long-term disease burden and heavy therapy costs. Today PGD has provided an opportunity for high-risk individuals to avoid the birth of a deaf child.

Bow hunter's syndrome in a patient with vertebral artery atresia, an arcuate foramen, and unilateral deafness: a case report

Bow hunter's syndrome (BHS) is a rare cause of vertebrobasilar insufficiency that occurs when the vertebral artery (VA) is occluded on rotation of the head and neck. This dynamic occlusion of the VA can occur anywhere along its course after it arises from the subclavian artery. Although most cases are associated with compression by osteophytes, cervical spondylosis, or lateral disc herniation, BHS has a highly variable clinical course that depends on the patient's specific anatomy. Therefore, it may be important for clinicians to be aware of anatomical variants that predispose individuals to BHS. Here, we report on a patient with BHS who was found to have two uncommon anatomical anomalies: an atretic right VA and a left-sided arcuate foramen.

A homozygous missense variant in HSD17B4 identified in a consanguineous Chinese Han family with type II Perrault syndrome

Background

Perrault syndrome is a rare multisystem disorder that manifests with sensorineural hearing loss in both sexes, primary ovarian insufficiency in females and neurological features. The syndrome is heterogeneous both genetically and phenotypically.

Case presentation

We reported a consanguineous family (two affected sisters) with Perrault syndrome. The proband had the characteristics of Perrault syndrome: ovarian dysgenesis, bilateral hearing loss and obvious neurological signs. Target genetic sequencing and triplet repeat primed PCR (TP-PCR) plus capillary electrophoresis was conducted to detect causative mutations in the proband. The detected variant was further confirmed in the proband and tested in other family members by Sanger sequencing. Both the proband and her sister were found homozygous for the novel variant HSD17B4 c.298G > T (p.A100S) with their parents heterozygous. Detected by western blot, the protein expression of HSD17B4 mutant was much lower than that of the wild type in SH-SY5Y cells transfected by HSD17B4 wild type or mutant plasmid, which indicated the pathogenicity of the HSD17B4 mutation.

Conclusions

Our findings supported that HSD17B4 was one of the genes contributing to Perrault syndrome with the likely pathogenic variant c.298G > T (p.A100S). Special manifestations of cerebellar impairment were found in cases caused by HSD17B4 mutations. Besides, attention should be paid to distinguish Perrault syndrome from D-bifunctional protein deficiency and hereditary ataxia.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-017-0453-0) contains supplementary material, which is available to authorized users.

Simultaneous Bilateral Anterior and Posterior Lenticonus in Alport Syndrome

Alport syndrome is an inherited disease characterized by progressive renal failure, hearing loss, and ocular abnormalities like anterior lenticonus, corneal opacities, cataract, central perimacular and peripheral coalescing fleck retinopathies, and temporal retinal thinning. Although anterior lenticonus is common in Alport syndrome, simultaneous anterior and posterior lenticonus is a rare presentation. We report a case of a 22-year-old female with simultaneous anterior and posterior lenticonus presentation in which ocular examination lead to the detection of Alport syndrome. The patient had sensorineural deafness as well as microscopic haematuria. Clear lens extraction was performed in both eyes to eliminate lenticular irregular astigmatism for visual rehabilitation.

Possible mechanisms for sensorineural hearing loss and deafness in patients with propionic acidemia

Propionic acidemia is an inborn error of metabolism caused by deficiency of the mitochondrial enzyme propionyl-CoA carboxylase. Sensorineural deafness and severe hearing loss have been described as long-term complications of this disease, however, the mechanism has not yet been elucidated. We have recently shown by patch clamping experiments and Western blots that acute and chronic effects of accumulating metabolites such as propionic acid, propionylcarnitine and methylcitrate on the KvLQT1/KCNE1 channel complex cause long QT syndrome in patients with propionic acidemia by inhibition of K⁺ flow via this channel. The same KvLQT1/KCNE1 channel complex is expressed in the inner ear and essential for luminal potassium secretion into the endolymphatic space. A disruption of this K⁺ flow results in sensorineural hearing loss or deafness. It can be assumed that acute and chronic effects of accumulating metabolites on the KvLQT1/KCNE1 channel protein may similarly cause the hearing impairment of patients with propionic acidemia.

Digenic mutations involving both the BSND and GJB2 genes detected in Bartter syndrome type IV

Bartter syndrome type IV, characterized by salt-losing nephropathies and sensorineural deafness, is caused by mutations of BSND or simultaneous mutations of both CLCNKA and CLCNKB. GJB2 is the primary causative gene for non-syndromic sensorineural deafness and associated with several syndromic sensorineural deafness. Owing to the rarity of Bartter syndrome, only a few mutations have been reported in the abovementioned causative genes. To investigate the underlying mutations in a Chinese patient with Bartter syndrome type IV, genetic analysis of BSND, CLCNKA, CLCNKB and GJB2 were performed by polymerase chain reaction and direct sequencing. Finally, double homozygous mutations c.22C > T (p.Arg8Trp) and c.127G > A (Val43Ile) were detected in exon 1 of BSND. Intriguingly, compound heterozygous mutations c.235delC (p.Leu79CysfsX3) and c.109G > A (p.Val37Ile) were also revealed in exon 2 of GJB2 in the same patient. No pathogenic mutations were found in CLCNKA and CLCNKB. Our results indicated that the homozygous mutation c.22C > T was the key genetic reason for the proband, and a digenic effect of BSND and GJB2 might contributed to sensorineural deafness. To our knowledge, it was the first report showing that the GJB2 gene mutations were detected in Bartter syndrome.

Phenotype variability of infantile-onset multisystem neurologic, endocrine, and pancreatic disease IMNEPD

Infantile-onset multisystem neurologic, endocrine, and pancreatic disease (IMNEPD) has been recently linked to biallelic mutation of the peptidyl-tRNA hydrolase 2 gene PTRH2. Two index patients with IMNEPD in the original report had multiple neurological symptoms such as postnatal microcephaly, intellectual disability, developmental delay, sensorineural deafness, cerebellar atrophy, ataxia, and peripheral neuropathy. In addition, distal muscle weakness and abnormalities of thyroid, pancreas, and liver were found. Here, we report five further IMNEPD patients with a different homozygous PTRH2 mutation, broaden the phenotypic spectrum of the disease and differentiate common symptoms and interindividual variability in IMNEPD associated with a unique mutation. We thereby hope to better define IMNEPD and promote recognition and diagnosis of this novel disease entity.

Clinical and molecular findings in three Moroccan families with distal renal tubular acidosis and deafness: Report of a novel mutation of ATP6V1B1 gene

BACKGROUND

Primary distal renal tubular acidosis (dRTA) is a rare genetic condition characterized by an impaired acid excretion by the intercalated cells in the renal collecting duct. Recessive forms of this disease are caused by mutations in tow major genes: ATP6V1B1 and ATP6V0A4. Causal mutations in ATP6V1B1 gene are classically associated with early sensorineural hearing loss, however cases of tubular acidosis with early deafness have also been described in patients with mutations in the ATP6V0A4 gene.

METHODS

The phenotype and genotype of three Moroccan consanguineous families with dRTA and deafness were assessed. Molecular analysis was performed by PCR amplification and direct sequencing of exon 12 of ATP6V1B1 gene.

RESULTS

A novel c.1169dupC frameshift mutation of ATP6V1B1 gene was identified in one family and the c.1155dupC North African mutation in the tow other families.

DISCUSSION AND CONCLUSION

In this report, we propose first line genetic testing based on screening of these two mutations both located in exon 12 of ATP6V1B1 gene in Moroccan patients with recessive form of dRTA associated to precocious hearing loss. Molecular diagnosis of dRTA leads to appropriate treatment and prevention of renal failure in affected individuals and to provide genetic counseling for families at risk.

A novel OPA1 mutation causing variable age of onset autosomal dominant optic atrophy plus in an Australian family

Pathogenic mutations in the OPA1 gene can be associated with Autosomal Dominant Optic Atrophy (ADOA). In approximately 20 % of patients with OPA1 mutations, a more complex neurodegenerative disorder with extraocular manifestations, known as ADOA Plus, can arise. 12 members of a multigenerational family were assessed clinically and screened for a genetic mutation in OPA1. Eight family members displayed manifestations consistent with ADOA Plus and four did not. Affected members of the oldest available generation displayed the most severe phenotype, which included severe optic atrophy, deafness, ptosis, ophthalmoplegia, proximal myopathy, neuropathy and ataxia. The next generation was less severely affected but several members displayed manifestations only after the fifth decade. Genetic analysis revealed a heterozygous variant in the OPA1 gene (c.1053T>A, p.Asp351Glu) that segregated with disease. The affected family members described here exhibited visual loss later than is typical for OPA1-related disease, as well as later onset of other neurological abnormalities in the fifth or sixth decades of life that progressed to severe neurological disability by the seventh decade. These findings expand the clinical spectrum of OPA1-related disease associated with a novel OPA1 mutation.

Perrault syndrome - a rare case report

Perrault syndrome is a rare disease comprising pure gonadal dysgenesis (46 XX) and sensorineural hearing loss in females and deafness alone in affected males. It is an autosomal recessive disorder. Over the years many additional features like marfanoid habitus and central nervous system findings have also been reported. Herein we report a case of sporadic Perrault syndrome in 18-year-old female who presented to our hospital with deaf mutism and primary amenorrhoea. On evaluation, the patient had hypergonadotropic hypogonadism, streak gonads and a normal karyotype (46 XX). Audiologic evaluation showed sensorineural deafness. The patient was started on hormone replacement therapy. She is on regular follow up. We present this case for its infrequent incidence and also to add to the ever expanding clinical spectrum of this disease.

A novel homozygous SLC19A2 mutation in a Portuguese patient with diabetes mellitus and thiamine-responsive megaloblastic anaemia

Thiamine-responsive megaloblastic anaemia (TRMA) is a rare syndrome where patients present with early onset diabetes mellitus, megaloblastic anaemia and sensorineural deafness. This report describes a new case of TRMA syndrome in a female patient of Portuguese descent, born to unrelated parents. The patient was found to have a novel homozygous change R397X in exon 4 of the SLC19A2 gene, leading to a premature stop codon. The patient’s diabetes and anaemia showed a good response to daily thiamine doses, reducing the daily insulin dose requirement. The report further indicates that TRMA is not only limited to consanguineous or ethnically isolated families, and should be considered as a differential diagnosis for patients presenting with suggestive clinical symptoms.

Sensorineural hearing loss in hemorrhagic dengue?

INTRODUCTION

Dengue is an acute febrile infectious disease, with high fever followed by symptoms flu-like. Dengue hemorrhagic fever (DHF) is a vascular leak syndrome and could present spontaneous bleeding and worsening of symptoms after some days. Dengue could have some ENT manifestations, however hearing loss is not one of them. Sudden hearing loss is considered as sensorineural or perceptual hearing loss with a sudden onset in a person without other prior otological history. The relation between infectious diseases and sudden hearing are been investigated, some viruses were already linked, but the relation between dengue virus and sudden hearing still remains unknown. This article has the goal of presenting a case of DHF that evolved with SSHL in his hospitalization process.

PRESENTATION OF CASE

We report a 60 years-male patient of with DHF who developed bilateral secretory otitis media and sensorineural hearing loss after the fifth day of onset of symptoms. His hearing loss remained even after 7 months and the patient was referred for hearing aid fitting.

DISCUSSION AND CONCLUSION

This is the first case report that brings together DHF and sudden hearing loss. In the development of this case no other cause to sudden hearing loss was found and the correlation between dengue and hearing loss was questioned. In the literature review was found that some viruses, as mumps virus, varicella-zoster virus and HSV-1 and HSV-2 are related to sudden hearing loss, all of them fit in the viral theory. Besides the viral theory of sudden hearing loss, there is the vascular theory that is the occlusion of the end artery that supplies the cochlea. DHF has a vascular commitment, and the hypothesis of a vascular cause could be elicited in this case. Many studies in this area are needed and this article has the objective of elicit the discussion about the subject. Could dengue be associated with sensorineural hearing loss?

Spontaneous and Partial Repair of Ribbon Synapse in Cochlear Inner Hair Cells After Ototoxic Withdrawal

Ototoxicity is one of the major causes of sensorineural deafness. However, it remains unclear whether sensorineural deafness is reversible after ototoxic withdrawal. Here, we report that the ribbon synapses between the inner hair cells (IHCs) and spiral ganglion nerve (SGN) fibers can be restored after ototoxic trauma. This corresponds with hearing restoration after ototoxic withdrawal. In this study, adult mice were injected daily with a low dose of gentamicin for 14 consecutive days. Immunostaining for RIBEYE/CtBP2 was used to estimate the number and size of synaptic ribbons in the cochlea. Hearing thresholds were assessed using auditory brainstem responses. Auditory temporal processing between IHCs and SGNs was evaluated by compound action potentials. We found automatic hearing restoration after ototoxicity withdrawal, which corresponded to the number and size recovery of synaptic ribbons, although both hearing and synaptic recovery were not complete. Thus, our study indicates that sensorineural deafness in mice can be reversible after ototoxic withdrawal due to an intrinsic repair of ribbon synapse in the cochlea.

Long-lasting uveitis remission and hearing loss recovery after rituximab in Vogt-Koyanagi-Harada disease

Vogt-Koyanagi-Harada disease (VKHD) is a multisystemic disorder characterized by granulomatous panuveitis variably combined with T cell-mediated neurologic and cutaneous manifestations. Early and aggressive treatment with systemic corticosteroids is the mainstay of treatment for VKHD. Additional use of immunosuppressants, intravenous immunoglobulins, and tumor necrosis factor-alpha inhibitors can help the most severely affected patients and work as corticosteroid-sparing agents. We report the case of a young woman with relapsing and multiresistant VKHD who demonstrated a stable remission of both uveitis and high-frequency hearing loss following rituximab intravenous administration (1 g. twice, 2 weeks apart, and 6 months later). A complete clinical response was observed 1 month since the first infusion, and no ocular relapses were recorded during the following year; in addition, audiometry showed a high-frequency hearing recovery in the right ear. Further observational studies are required to define the role of CD20 inhibition in the management of VKHD.

Preimplantation genetic diagnosis: its role in prevention of deafness

Deafness is a global problem. In India deafness ranges from 4 % in urban to 11 % in rural and slum areas, out of which 50 % is conductive hearing loss hence curable. Genetic transmission accounts for 50 % of the cases of congenital deafness, and of these, around 30 % are syndromic and 70 % are non-syndromic. Genetic counseling is going to make aware the parents of all appropriate treatments. Preimplantation genetic diagnosis can help to have a baby free from genetic deafness. Procedure is almost safe, harmless, non-invasive and ethically acceptable. While Amniocentesis is a non-invasive method, prenatal genetic testing through Chorionic villous sampling is invasive. The connexin 26 (CX26W 24X) mutations are the most common cause of non-syndromic hearing loss and easy to identify by polymerase chain reaction. There is always co-morbidity after cochlear implantation and the person remains handicapped while baby after PGD shall be having healthy normal life and person prone to environmental factors may be counseled and guided to prevent deafness in next generation. Public must be made aware of noise pollution, tobacco toxicity and consanguinity. The Obstetrician and Pediatrician apart from ENT surgeon should be involved to prevent antenatal or neonatal deafness.

Pendred syndrome with retrosternal goitre- a rare case report

Pendred syndrome is a recessively inherited disorder characterized by goiter associated with sensory-neural deafness. The thyroid glands of affected individuals cannot organify iodide efficiently due to a defective gene in chromosome 7. Here we report a case of Pendred syndrome with retrosternal goitre.

Pseudoexfoliation syndrome and sensorineural hearing loss

INTRODUCTION

Pseudoexfoliation syndrome (PXS) occurs due to the deposition of extracellular fibrillar materials on the anterior chamber of the eye. This syndrome has been considered to be part of a systemic disease with the potential involvement of the inner ear called sensoroneural hearing loss (SNHL). In this study, we aimed on evaluating SNHL within PXS patients in Iran to compare them with other international reports.

MATERIALS AND METHODS

In total, 33 patients with PXS and 33 age and sex matched controls were enrolled prospectively in a case-control study. Both groups underwent complete ophthalmologic and otorhinolaryngologic examinations and pure tone audiometry (PTA) testing. Six frequencies (0.25, 0.5, 1, 2, 3, 4 and 6 KHz) were evaluated for PTA in the same ethnic group in order to select the case and control individuals. Data were analyzed using t-test and chi-square test.

RESULTS

Forty-nine out of 66 ears (75.2%) in the PXS group and 27 ears (40.9%) in the control group had SNHL (P<0.001). No significant difference was found between the existence of exfoliative glaucoma (EXG) and SNHL in the PXS patients (P=0.768).

CONCLUSION

Our results indicate a significant association between PXS and SNHL and may support the systemic nature of this disease.