Audiometric abnormalities in children with Gaucher disease type 3

Histologic and ultrastructural study of intracranial Gaucheroma causing deafness in a patient with Gaucher disease type 3: Effects of substrate reduction therapy

Hearing loss is frequently associated with Gaucher disease (GD). Gaucher cells are enlarged reticuloendothelial cells containing glucocerebroside in the lysosomes due to deficiency of the glucocerebrosidase. Gaucheromas consist of accumulated Gaucher cells. Gaucher cells accumulate in variable tissues including the liver, spleen, bone marrow, and the middle ear and the mastoid causing conductive hearing loss. Neurons and astrocytes in the central nervous system are affected in neuronopathic GD leading to sensorineural hearing loss. Gaucheromas can develop even in patients treated with enzyme replacement therapy (ERT). We report a 19-year-old female patient with GD type 3 who developed profound bilateral hearing loss associated with intracranial Gaucheroma. Combination therapy of ERT with imiglucerase and substrate reduction therapy (SRT) with eliglustat significantly decreased the size of Gaucher cells and cleared the characteristic microtubular structures in the lysosomes in Gaucher cells. Early implementation of SRT may prevent at least conductive hearing impairment in GD although it may not prevent sensorineural hearing loss due to inner hair cell dysfunction which is also known to be associated with neuronopathic GD.

A review of type 3 Gaucher disease: unique neurological manifestations and advances in treatment

Gaucher disease (GD) is a rare lysosomal storage disease that is caused by mutations in the GBA gene. It is classified into three main phenotypes according to the patient's clinical presentation. Of these, chronic neuronopathic GD (GD3) is characterized by progressive neurological damage. Understanding the unique neurological manifestations of GD3 has important diagnostic and therapeutic implications. Our article summarizes the neurological symptoms specific to GD3 and related therapeutic advances, and it highlights the relevance of the gene to clinical symptoms, so as to provide a reference for the diagnosis and treatment of GD3.

A case of gaucher disease with a rare complication of gaucheroma and protein-losing enteropathy

This case report describes a patient initially diagnosed with Gaucher disease (GD) with type I with homozygous mutation c.1448T > C p. (Leu483Pro) at age of 2, presenting with hepatosplenomegaly and cytopenia. Imiglucerase replacement therapy was initiated. At age 17, bilateral hearing loss developed, with subsequent Cranial MRI revealing thalamic damage, leading to a reclassification as type 3 GD. By age of 20, the patient presented with a range of symptoms, including abdominal pain, diarrhea, hypoproteinemia, multiple lymphadenopathy, edema, and Gaucher cell infiltration in the lymph nodes. Comprehensive diagnosis identifies Gaucher tumor and protein-losing enteropathy. Imiglucerase therapy at 90-120 U/kg every 2 weeks significantly improved clinical symptoms, emphasizing the importance of tailored interventions for managing GD manifestations.

Clinical Outcomes of Patients with Chronic Neuropathic Form of Gaucher Disease in the Spanish Real-World Setting: A Retrospective Study

This was a retrospective, multicenter study that aimed to report the characteristics of type 3 Gaucher disease (GD3) patients in Spain, including the genotype, phenotype, therapeutic options, and treatment responses. A total of 19 patients with GD3 from 10 Spanish hospitals were enrolled in the study (14 men, 5 women). The median age at disease onset and diagnosis was 1 and 1.2 years, respectively, and the mean age at follow-up completion was 12.37 years (range: 1-25 years). Most patients exhibited splenomegaly (18/19) and hepatomegaly (17/19) at the time of diagnosis. The most frequent neurological abnormalities at onset were psychomotor retardation (14/19) and extrinsic muscle disorders (11/19), including oculomotor apraxia, supranuclear palsy, and strabismus. The L444P (c.1448T>C) allele was predominant, with the L444P (c.1448T>C) homozygous genotype mainly associated with visceral manifestations like hepatosplenomegaly, anemia, and thrombocytopenia. All patients received enzyme replacement therapy (ERT); other treatments included miglustat and the chaperone (ambroxol). Visceral manifestations, including hepatosplenomegaly and hematological and bone manifestations, were mostly controlled with ERT, except for kyphosis. The data from this study may help to increase the evidence base on this rare disease and contribute to improving the clinical management of GD3 patients.

The Spectrum of Neurological and Sensory Abnormalities in Gaucher Disease Patients: A Multidisciplinary Study (SENOPRO)

Gaucher disease (GD) has been increasingly recognized as a continuum of phenotypes with variable neurological and sensory involvement. No study has yet specifically explored the spectrum of neuropsychiatric and sensory abnormalities in GD patients through a multidisciplinary approach. Abnormalities involving the nervous system, including sensory abnormalities, cognitive disturbances, and psychiatric comorbidities, have been identified in GD1 and GD3 patients. In this prospective study, named SENOPRO, we performed neurological, neuroradiological, neuropsychological, ophthalmological, and hearing assessments in 22 GD patients: 19 GD1 and 3 GD3. First, we highlighted a high rate of parkinsonian motor and non-motor symptoms (including high rates of excessive daytime sleepiness), especially in GD1 patients harboring severe glucocerebrosidase variants. Secondly, neuropsychological evaluations revealed a high prevalence of cognitive impairment and psychiatric disturbances, both in patients initially classified as GD1 and GD3. Thirdly, hippocampal brain volume reduction was associated with impaired short- and long-term performance in an episodic memory test. Fourthly, audiometric assessment showed an impaired speech perception in noise in the majority of patients, indicative of an impaired central processing of hearing, associated with high rates of slight hearing loss both in GD1 and GD3 patients. Finally, relevant structural and functional abnormalities along the visual system were found both in GD1 and GD3 patients by means of visual evoked potentials and optical coherence tomography. Overall, our findings support the concept of GD as a spectrum of disease subtypes, and support the importance of in-depth periodic monitoring of cognitive and motor performances, mood, sleep patterns, and sensory abnormalities in all patients with GD, independently from the patient's initial classification.

Molecular Mechanisms and Biological Functions of Autophagy for Genetics of Hearing Impairment

The etiology of hearing impairment following cochlear damage can be caused by many factors, including congenital or acquired onset, ototoxic drugs, noise exposure, and aging. Regardless of the many different etiologies, a common pathologic change is auditory cell death. It may be difficult to explain hearing impairment only from the aspect of cell death including apoptosis, necrosis, or necroptosis because the level of hearing loss varies widely. Therefore, we focused on autophagy as an intracellular phenomenon functionally competing with cell death. Autophagy is a dynamic lysosomal degradation and recycling system in the eukaryotic cell, mandatory for controlling the balance between cell survival and cell death induced by cellular stress, and maintaining homeostasis of postmitotic cells, including hair cells (HCs) and spiral ganglion neurons (SGNs) in the inner ear. Autophagy is considered a candidate for the auditory cell fate decision factor, whereas autophagy deficiency could be one of major causes of hearing impairment. In this paper, we review the molecular mechanisms and biologic functions of autophagy in the auditory system and discuss the latest research concerning autophagy-related genes and sensorineural hearing loss to gain insight into the role of autophagic mechanisms in inner-ear disorders.

Auditory brainstem response

The auditory brainstem response (ABR), consisting of five to six vertex-positive peaks with separation of about 0.8ms, is very sensitive to factors that affect conduction velocity and hence ABR wave latencies in the brainstem auditory pathways. In addition, disorders causing dissynchronization of neural activity result in an amplitude decrease or disappearance of ABR peaks. The opposite effects occur in the maturation process, which takes about 2 years postterm; here conduction velocity increases quickly to its adult value, but synaptic delays being sensitive to synchronous release of transmitter substance take considerably longer. In neurological disorders, those that cause dissynchrony, such as auditory neuropathy and vestibular schwannoma, Gaucher disease, and Krabbe disease, the (longer latency) ABR peaks are reduced or absent. Effects on neural conduction, resulting in increased ABR interwave latencies, are found in vestibular schwannomas, Bell's palsy, Duane retraction syndrome, Marcus Gunn ptosis, and various encephalomyopathies. These measures allow an assessment of the parts of the brainstem that are involved.

Hearing loss in children with Fabry disease

BACKGROUND

Hearing loss (HL) is a well-known feature of Fabry disease (FD). Its presence and characteristics have mainly been studied in adult patients, while only limited data are available on the presence and degree of HL in children with FD. This prompted us to study hearing sensitivity in pediatric FD patients.

METHODS

All available audiograms of the Dutch and Norwegian children with FD were retrospectively collected. First, hearing sensitivity was determined by studying hearing thresholds at low, high, and ultra-high frequencies in children with FD and comparing them to zero dB HL, i.e., healthy children. In addition, the presence and type of slight/mild HL (defined as hearing thresholds at low frequencies of 25-40 dB HL) and moderate to severe HL (hearing thresholds >40 dB HL) at first visit were analyzed. If available, follow-up data were used to estimate the natural course of hearing sensitivity and HL in children with FD.

RESULTS

One-hundred-thirteen audiograms of 47 children with FD (20 boys, median age at first audiogram 12.0 (range 5.1-18.0) years) were analyzed. At baseline, slight/mild or moderate to severe HL was present in three children (6.4%, 2 boys). Follow-up measurements showed that three additional children developed HL before the age of 18. Of these six children, five had sensorineural HL, most likely caused by FD. Compared to healthy children (zero dB HL), FD children showed increased hearing thresholds at all frequencies (p < 0.01), which was most prominent at ultra-high frequencies (>8 kHz). Hearing sensitivity at these ultra-high frequencies deteriorated in a period of 5 years of follow-up.

CONCLUSION

A minority of children with FD show slight/mild or moderate to severe HL, but their hearing thresholds are poorer than the reference values for normal-hearing children. Clinical trials in FD children should demonstrate whether HL can be prevented or reversed by early treatment and should specifically study ultra-high frequencies.

Role of saposin C and D in auditory and vestibular function

OBJECTIVES/HYPOTHESIS

Saposins are small proteins derived from a precursor protein, prosaposin. Each of the four saposins (A-D) is necessary for the activity of lysosomal glycosphingolipid hydrolases. Individual saposin mutations lead to lysosomal storage diseases, some of which are associated with hearing loss. Here we evaluate the effects of the loss of saposins C and D on auditory and vestibular function in transgenic mice.

METHODS

Transgenic mice with either loss of saposin C function or a combined loss of saposin C + D function were studied. Light microscopy and immunofluorescence were used to evaluate histologic and morphologic changes in the auditory and vestibular organs. Acoustic brainstem response thresholds and distortion product otoacoustic emissions were used to study the auditory phenotype.

RESULTS

A null mutation of saposin C did not result in any identifiable histologic changes or loss of hearing through postnatal day 55. Combined losses of saposins C and D similarly did not result in any changes in organ of Corti histology or loss of hearing. However, inclusions within the vestibular end organs was noted, consistent with afferent and efferent neuronal sprouting, although to a much milder degree than seen in the previously studied prosaposin knockout mouse.

CONCLUSIONS

Loss of saposin C and D function, although causing mild phenotypic changes in the vestibular end organs, otherwise results in minimal functional impairment and no changes in the auditory system. It is more likely that the auditory and vestibular effects of the loss of prosaposin are mediated through the actions of saposin A and/or B.

LEVEL OF EVIDENCE

NA.

Middle-ear involvement in type I Gaucher's disease - a unique case

OBJECTIVE

Gaucher's disease is a rare autosomal recessive lysosomal storage disease. We describe a unique case of middle-ear involvement presenting with hearing loss.

CASE REPORT

A five-year-old boy with known Gaucher's disease presented with bilateral hearing impairment and conductive hearing loss on pure tone audiometry with flat tympanometry traces.

INTERVENTION

Exploratory Tympanomastoidectomy revealed inflammatory material filling the mastoid and the middle ear. Histological analysis confirmed Gaucher cell infiltrates.

CONCLUSION

This is the first detailed report in the english language literature of Gaucher's disease affecting the middle ear and the mastoid. We discuss the disease process and suggest future management options.

Evoked potentials and neurocognitive functions in pediatric Egyptian Gaucher patients on enzyme replacement therapy: a single center experience

BACKGROUND

Effectiveness of enzyme replacement therapy (ERT) in reverting hematologic, skeletal, and visceral symptoms in Gaucher disease (GD) has been demonstrated, although, its efficacy in neurologic involvement is still debated.

AIM

We evaluated the extent of neuro-cognitive dysfunction using brain stem evoked potential in GD3 patients, age-matched controls, and GD1 patients without neurological manifestations served as disease control group.

METHODS

Study included 56 GD (36 had type 1, 20 had type 3) under ERT. Investigations included complete blood count, beta glucosidase assay in peripheral leucocytes, plasma chitotriosidase and bone marrow examination, electroencephalography, brain stem auditory (AEP), somatosensory (SSEP) and visual evoked potentials (VEP) as well as IQ testing.

RESULTS

Both types of GD showed significantly higher mean latency at 75 on left eye, lower PP amplitude ratio, higher latency at 75, 100, 145, lower amplitude, and higher Lat Diff LT-RT ms and Lt-Rt % compared to controls (p < 0.05) with no difference between both groups in other values of VEP. Both groups showed significantly prolonged latency of N 13-19 compared to controls (p < 0.05) with positive correlation between age and duration of therapy with parameters of SSEP (p < 0.01). Both groups of GD had significantly prolonged latency of the mean waves of AEP compared to controls (p < 0.05) with no significant difference between both groups. There was a negative correlation between age and waves II, III, I-III, I-V and threshold values of AEP. IQ level was positively correlated with AEP values. Severity scoring tool was positively correlated with AEP and SSEP values.

CONCLUSIONS

Electrophysiological abnormalities were present in both types of GD and have been correlated to cognitive function and disease characteristics.

Auditory system involvement in late onset Pompe disease: a study of 20 Italian patients

Glycogen storage disease type II (GSD II), also known as Pompe disease, is an autosomal recessive inherited disorder caused by a reduced activity of acid alpha glucosidase (GAA). Two different clinical entities have been described: rapidly fatal infantile and late onset forms. Hearing loss has been described in classic infantile Pompe patients but rarely in late onset cases. The main purpose of this study was to investigate the involvement of the auditory system in a cohort of Italian patients with late onset GSD II. We have enrolled 20 patients, 12 males and 8 females. The auditory system assessment included speech and pure tone audiometry, impedance audiometry and auditory brainstem responses (ABR). A combined interpretation of those tests allowed us to define the origin of the hearing impairment (sensorineural, conductive or mixed). Clinically, all patients but one denied subjective hearing disturbances. On the other hand, audiological evaluation revealed that 21/40 patient ears (52.5%) had a hearing impairment: 57% had a sensorineural deficit, 33% showed a conductive hearing loss whereas 10% presented with a mixed pattern. Our study revealed that, in this group of GSDII late onset patients, the auditory system impairment was more frequently present than thought with a prominent cochlear involvement. Our results emphasize the importance of a routinely auditory function evaluation in all forms of Pompe disease.

[Clinical characteristics of the neurological forms of Gaucher's disease]

Gaucher's disease is the most prevalent disease of accumulation of glycosphingolipids. Neurological involvement is used to classify the different types of the disease. Type 1 affects approximately 90% of patients, and visceral manifestations and bone marrow, without affecting the nervous system. Type 2 is considered a severe form of disease with severe nervous system and death within two years. Type 3 is late, slowly progressive neurological symptoms and survival until the third decade. Besides these classical syndromes, the best knowledge of the disease related to the existence of national registries, the increased survival of patients resulting from replacement therapy, and demonstration of the behavior of glucocerebrosidase mutations as a risk factor of neurodegenerative diseases, has expanded the clinical phenotype and altered the traditional classification of the disease.

Hearing in adults with Pompe disease

Hearing loss has been recognized as an important cause of morbidity in infants with Pompe disease, a metabolic disorder caused by deficiency of acid α-glucosidase. It is unknown whether hearing is also affected in adult Pompe patients. We have studied the prevalence, severity, and type of hearing loss in 58 adult patients using tympanometry and pure-tone audiometry. Compared to normative data (International Organisation for Standardisation standard 7029), 72% of patients had impaired hearing thresholds at one or more frequencies in at least one ear. All measured frequencies were equally affected. All patients had a sensorineural type of hearing loss, pointing to cochlear or retrocochlear pathology. Categorised according to the standards of the World Health Organisation 21% of patients had a clinically relevant hearing loss (16% slight, 3% moderate, 2% profound). Though this suggests that hearing loss occurs in a considerable number of patients with Pompe disease, this prevalence is similar to that in the general population. Therefore, we conclude that hearing loss is not a specific feature of Pompe disease in adults.

Hearing loss in Pompe disease revisited: results from a study of 24 children

Little information is available regarding the auditory function in Pompe patients. Hearing loss has been reported in classic infantile patients, but it is still unknown whether central nervous system involvement interferes with auditory function and whether enzyme replacement therapy can improve hearing. Auditory function has not been studied in children with milder forms of the disease. We analyzed repetitive auditory brainstem response measurements and pure tone audiometry in 24 children with Pompe disease. Only 1 of 13 patients with milder phenotypes showed recurrent conductive hearing loss, while 10 out of 11 classic infantile patients had sensorineural hearing defects. These patients also had a high prevalence of conductive hearing loss. Five patients showed evidence of mild retrocochlear pathology, suggestive of glycogen accumulation in the central nervous system. Hearing loss persisted during therapy in all patients. The results emphasize the need for careful monitoring of auditory function in classic infantile Pompe patients, and for early implementation of hearing aids to protect speech and language development.

Study of multimodal evoked potentials in patients with type 1 Gaucher's disease

To detect early subclinical nervous dysfunction in Gaucher's disease type 1, we carried out motor, brainstem auditory, visual, and somatosensory evoked potentials in 17 patients with Gaucher's disease type 1. Central motor evoked potential abnormalities were found in nine patients (69.2%), consisting of an increased motor threshold in all, with prolonged central motor conduction time in two patients. Brainstem auditory evoked potentials were abnormal in five patients (31.2%), and the most frequent abnormality was a bilateral increased I-III interpeak latency. Visual evoked potentials showed a delayed latency of the P100 wave in four patients (25%). Somatosensory evoked potential abnormalities were found in three patients (18.7%), consisting of an increased N13-N20 interval in two patients and a not reproducible N13 wave in one patient. Our findings suggest that the multimodal evoked potential approach provides information about nervous subclinical damage in Gaucher's disease type 1; transcranial magnetic stimulation proved to be the most sensitive tool. Early detection of subclinical neurologic dysfunction can be useful in view of more effective therapeutic strategies.

Pediatric non-neuronopathic Gaucher disease: presentation, diagnosis and assessment. Consensus statements

Gaucher disease is caused by defective activity of glucocerebrosidase. The resulting accumulation of glucocerebroside in the lysosomes of visceral macrophages in various tissue and organ compartments leads to multiple manifestations, including hepatosplenomegaly, anemia, thrombocytopenia, growth retardation and skeletal disease. The most prevalent form of Gaucher disease is the non-neuronopathic (type 1) variant, which lacks primary involvement of the central nervous system. Traditionally, this has been referred to as the 'adult type'; however, 66% of individuals with symptomatic non-neuronopathic Gaucher disease manifest in childhood. Onset in childhood is usually predictive of a severe, rapidly progressive phenotype and children with non-neuronopathic Gaucher disease are at high risk for morbid complications. Enzyme therapy with recombinant human glucocerebrosidase in childhood can restore health in reversible manifestations and prevent the development of irreversible symptoms. A heightened focus on pediatric Gaucher disease is therefore needed. Although some correlation has been found between genotype and phenotype, mutation analysis is of limited value in disease prognosis. Management of pediatric Gaucher disease should be underpinned by a thorough assessment of the phenotype at baseline with regular monitoring thereafter. Excluding neuronopathic disease is recommended as the first step. Subsequently, baseline evaluation should focus on staging of different storage tissues, particularly the bone the involvement of which results in the greatest long-term morbidity. These organ assessments are recommended because bone disease severity may not correlate with disease severity in other organs and vice versa. In addition, different organs may respond differently to therapy. Initial assessment of each organ system can enable setting of realistic and individualized goals.

CONCLUSION

A thorough approach to baseline assessment will improve the understanding of childhood Gaucher disease, optimizing management to minimize impairment of growth and development and prevent irreversible symptoms.

Paediatric non-neuronopathic Gaucher disease: recommendations for treatment and monitoring

In individuals with non-neuronopathic Gaucher disease, childhood manifestations are usually predictive of a more severe phenotype. Although children with Gaucher disease are at risk of irreversible disease complications, early intervention with an optimal dose of enzyme therapy can prevent the development of complications and ensure adequate, potentially normal, development through childhood and adolescence. Very few, if any, children diagnosed by signs and symptoms should go untreated. Evidence suggests that disease severity, disease progression and treatment response in different organs where glucocerebroside accumulates are often non-uniform in affected individuals. Therefore, serial monitoring of the affected compartments is important. This should include a thorough physical examination at 6- to 12-monthly intervals. Neurological assessment should be performed to rule out neurological involvement and should be undertaken periodically thereafter in children who are considered to have risk factors for developing neuronopathic disease. Haematological and biochemical markers, such as haemoglobin, platelet counts and chitotriosidase levels, should be assessed every 3 months initially, but when clinical goals have been met through treatment with enzyme therapy, the frequency can be reduced to every 12 to 24 months. Careful monitoring of bone disease is vitally important, as the resulting sequelae are associated with the greatest level of morbidity. By combining various imaging modalities, the skeletal complications of non-neuronopathic Gaucher disease can be effectively monitored so that irreversible skeletal pathology is avoided and pain due to bone involvement is diminished or eliminated. Monitoring must include regular psychosocial, functional status and quality-of-life evaluation, as well as consistent assessment of therapeutic goal attainment and necessary dosage adjustments based on the patient's progress.

CONCLUSION

Through comprehensive and serial monitoring, ultimately, a therapeutic dose of enzyme therapy that achieves sustained benefits can be found for each child with non-neuronpathic Gaucher disease.