Infantile Neuroaxonal Dystrophy: Case Report and Review of Literature.

Infantile neuroaxonal dystrophy (INAD) is a rare neurodegenerative disorder affecting 1:1,000,000 children. It results from pathogenic variants in the PLA2G6 gene located on chromosome 22q13.1. The onset of symptoms usually occurs between 6 and 18 months, causing developmental regression leading to debilitating symptoms such as muscle weakness, dementia, and loss of basic skills. Eventually, it progresses to life-threatening symptoms, including breathing difficulties, which limit the life expectancy to 5-10 years. While potential genetic therapies for treatment are being developed, they are yet to be approved for use, and management remains essentially supportive. This case report is about a nine-year-old Pakistani girl with INAD. She presented with recurrent chest infections, developmental regression, loss of speech, paralysis, hypertension, and eventually breathing difficulties. Brain magnetic resonance imaging and genetic testing confirmed the diagnosis. This case posed diagnostic challenges in view of its overlapping clinical presentation. Through this report, we aim to raise awareness about this condition among practitioners, outline the importance of genetic counseling in susceptible couples, and suggest potential areas of further research.

Cerebrospinal fluid and serum proteomic profiles accurately distinguish neuroaxonal dystrophy from cervical vertebral compressive myelopathy in horses.

BACKGROUND: Cervical vertebral compressive myelopathy (CVCM) and equine neuroaxonal dystrophy/degenerative myeloencephalopathy (eNAD/EDM) are leading causes of spinal ataxia in horses. The conditions can be difficult to differentiate, and there is currently no diagnostic modality that offers a definitive antemortem diagnosis. OBJECTIVE: Evaluate novel proteomic techniques and machine learning algorithms to predict biomarkers that can aid in the antemortem diagnosis of noninfectious spinal ataxia in horses. ANIMALS: Banked serum and cerebrospinal fluid (CSF) samples from necropsy-confirmed adult eNAD/EDM (n = 47) and CVCM (n = 25) horses and neurologically normal adult horses (n = 45). METHODS: . A subset of serum and CSF samples from eNAD/EDM (n = 5) and normal (n = 5) horses was used to evaluate the proximity extension assay (PEA). All samples were assayed by PEA for 368 neurologically relevant proteins. Data were analyzed using machine learning algorithms to define potential diagnostic biomarkers. RESULTS: Of the 368 proteins, 84 were detected in CSF and 146 in serum. Eighteen of 84 proteins in CSF and 30/146 in serum were differentially abundant among the 3 groups, after correction for multiple testing. Modeling indicated that a 2-protein test using CSF had the highest accuracy for discriminating among all 3 groups. Cerebrospinal fluid R-spondin 1 (RSPO1) and neurofilament-light (NEFL), in parallel, predicted normal horses with an accuracy of 87.18%, CVCM with 84.62%, and eNAD/EDM with 73.5%. MAIN LIMITATIONS: Cross-species platform. Uneven sample size. CONCLUSIONS AND CLINICAL IMPORTANCE: Proximity extension assay technology allows for rapid screening of equine biologic matrices for potential protein biomarkers. Machine learning analysis allows for unbiased selection of highly accurate biomarkers from high-dimensional data.

Time course of serum neuron-specific enolase levels from infancy to early adulthood in a female patient with beta-propeller protein-associated neurodegeneration.

Beta-propeller protein-associated neurodegeneration (BPAN), a subgroup of neurodegeneration with brain iron accumulation, is typically characterized by non-progressive global developmental delay and seizures in childhood, followed by progressive neurological decline with parkinsonism and dementia in adolescence or early adulthood. It is difficult to clinically identify a patient with BPAN in childhood. Recent studies reported that serum levels of neuron-specific enolase (NSE) were elevated in children with BPAN. We reviewed the time course of serum NSE levels in a 21-year-old female patient genetically diagnosed (a de novo WDR45 variant c.268A > T) with BPAN, which was suspected based on prolonged elevation of serum NSE. There was an overall tendency for serum NSE levels to decrease in a stepwise fashion. The peak serum NSE level was observed during the first 2 years of age and then decreased rapidly in 1 year. High serum NSE levels persisted between 3 and 11 years of age. Subsequently, serum NSE levels decreased and plateaued after 13 years of age. There were tendencies for both blood AST and LDH levels to decrease over time in parallel with serum NSE levels. Serum NSE levels may be a diagnostic biomarker of BPAN in children but becomes of less value in identifying a patient with BPAN after childhood.

Equine Neuroaxonal Dystrophy and Degenerative Myeloencephalopathy.

Neuroaxonal degenerative disease in the horse is termed equine neuroaxonal dystrophy (eNAD), when pathologic lesions are localized to the brainstem and equine degenerative myeloencephalopathy (EDM) and degenerative changes extend throughout the spinal cord. Both pathologic conditions result in identical clinical disease, most commonly characterized by the insidious onset of ataxia during early development. However, later onset of clinical signs and additional clinical features, such as behavior changes, is also observed. A definitive diagnosis of eNAD/EDM requires histologic evaluation of the caudal medulla and cervicothoracic spinal cord. Strong evidence has suggested that eNAD/EDM is an inherited disorder and there seems to be a role for vitamin E acting as an environmental modifier to determine the overall severity of the phenotype of horses affected with eNAD/EDM.

Neurodegeneration with brain iron accumulation: Characterization of clinical, radiological, and genetic features of pediatric patients from Southern India.

BACKGROUND: Neurodegeneration with brain iron accumulation (NBIA) is a group of rare inherited neurodegenerative disorders. Ten types of NBIA are known. Studies reporting various NBIA subtypes together are few. This study was aimed at describing clinical features, neuroimaging findings, and genetic mutations of different NBIA group disorders. METHODS: Clinical, radiological, and genetic data of patients diagnosed with NBIA in a tertiary care centre in Southern India from 2014 to 2020 was retrospectively collected and analysed. RESULTS: In our cohort of 27 cases, PLA2G6-associated neurodegeneration (PLAN) was most common (n = 13) followed by Pantothenate kinase-associated neurodegeneration (PKAN) (n = 9). We had 2 cases each of Mitochondrial membrane-associated neurodegeneration (MPAN) and Beta-propeller protein- associated neurodegeneration (BPAN) and 1 case of Kufor-Rakeb Syndrome (KRS). Walking difficulty was the presenting complaint in all PKAN cases, whereas the presentation in PLAN was that of development regression with onset at a mean age of 2 years. Overall, 50% patients of them presented with development regression and one-third had epilepsy. Presence of pyramidal signs was most common examination feature (89%) followed by one or more eye findings (81%) and movement disorders (50%). Neuroimaging was abnormal in 24/27 cases and cerebellar atrophy was the commonest finding (52%) followed by globus pallidus hypointensities (44%). CONCLUSIONS: One should have a high index of clinical suspicion for the diagnosis of NBIA in children presenting with neuroregression and vision abnormalities in presence of pyramidal signs or movement disorders. Neuroimaging and ophthalmological evaluation provide important clues to diagnosis in NBIA syndromes.

Cerebral folate transporter deficiency syndrome in three siblings: Why genetic testing for developmental and epileptic encephalopathies should be performed early and include the FOLR1 gene.

Cerebral folate transporter deficiency syndrome, caused by FOLR-1 mutations is characterized by late infantile onset, severe developmental regression, epilepsy, and leukodystrophy. An extremely low concentration of 5-methyltetrahydrofolate in the cerebrospinal fluid provides a crucial clue to its diagnosis and is a treatment target. Oral or intravenous folinic acid (5-formyltetrahydrofolate) administration improves clinical symptoms and brain magnetic resonance imaging (MRI) findings. We describe three siblings carrying a novel homozygous FOLR1 nonsense mutation, that were referred due to intractable epilepsy and progressive neurological decline. Brain MRI showed hypomyelination and cerebellar atrophy. Folinic acid (oral and intravenous) supplementation, initiated after over 15 years illness, has failed to result in any sizeable clinical or neurophysiological improvement. Cerebral folate transport deficiency bears overlapping clinical features with many severe developmental encephalopathies. It is crucial to recognize FOLR1 signs and establish an early clinical and molecular diagnosis in order to provide timely folinic acid treatment and improve outcome.

A 3'-truncating FTL mutation associated with hypoferritinemia without neuroferritinopathy.

Mutations in the gene for the ferritin light chain (FTL) often present with hypoferritinemia associated with progressive, late onset extrapyramidal dysfunction. However, it has been suggested that some FTL mutations may impact ferritin levels without any neurological manifestations. We report on a FTL mutation in a three generation family with autosomal dominant hypoferritinemia without neurodegeneration. The 4 year old proband was identified with longstanding history of hypoferritinemia without evidence of anemia. Brain MRI did not show any evidence of iron deposition. It was found that the patient's 19 month old sister, 30 year old mother and 58 year old maternal grandmother also had hypoferritinemia and normal iron levels. Over the next nine years, none of these persons had any evidence of neurological dysfunction, including movement disorders, gait disturbances, behavioral or psychiatric dysfunction. Whole exome sequencing revealed a heterozygous interstitial deletion of at least 5 kb within cytogenic band 19q13.33 involving exons 3 and 4 of FTL in all affected family members. This 3' FTL deletion is predicted to create a significantly truncated protein product. We conclude that haploinsufficiency of FTL may be associated with hypoferritinemia without neurological dysfunction.

Determination of vitamin E and its metabolites in equine urine using liquid chromatography-mass spectrometry.

Equine neuroaxonal dystrophy/degenerative myeloencephalopathy (eNAD/EDM) is a hereditary, deteriorating central nervous disease in horses. Currently, the only way to confirm eNAD/EDM is through a postmortem histological evaluation of the central nervous system. Vitamin E, specifically the isoform alpha-tocopherol (α-TP), is known to protect eNAD/EDM susceptible horses from developing the clinical phenotype. While vitamin E is an essential nutrient in the diet of horses, there are no diagnostic tests able to quantitate vitamin E and its metabolites in urine. An ultra-performance liquid chromatography-atmospheric-pressure chemical ionization mass spectrometry (UPLC-APCI-MS/MS) method was developed and validated following acidic hydrolysis and solid phase extraction to quantitate vitamin E and its metabolites in equine urine. A blank control horse urine matrix was used and spiked with different concentrations of analytes to form a standard curve using either alpha-tocopherol-d6 or chlorpropamide as the internal standard. Inter-day and intra-day statistics were performed to evaluate the method for accuracy (90% to 116%) and precision (0.75% to 14%). Matrix effects, percent recovery, and stability were also assessed. The method successfully analyzed alpha-carboxyethyl hydroxychroman (α-CEHC), alpha-carboxymethylbutyl hydroxychromans (α-CMBHC), gamma-carboxyethyl hydroxychroman γ-CEHC, and α-TP concentrations in urine to determine a baseline levels of analytes in healthy horses, and can be used to determine concentrations of vitamin E metabolites in equine urine allowing for its evaluation as a diagnostic approach in the treatment of eNAD/EDM.

Dominant mitochondrial membrane protein-associated neurodegeneration (MPAN) variants cluster within a specific C19orf12 isoform.

Mitochondria membrane protein-associated neurodegeneration (MPAN) neurodegenerative disorder is typically associated with biallelic C19orf12 variants. Here we describe a new and review candidate previous monoallelic de novo C19orf12 variants to define loss of function mutations located in the putative non-membrane spanning C19orf12 isoform as the potential basis of monoallelic MPAN.

BPAN manifesting with febrile seizures and language delay: a case report from Brazil

Neurodegeneration with brain iron accumulation (NBIA) is a complex group of hereditary progressive neurodegenerative diseases characterized by deposition of iron in the basal ganglia. Twelve genetic forms of this disorder have been identified in previous studies. Though they have different inheritance mechanisms all are usually associated with abnormal brain MRI findings. One of NBIA types is an X-linked disorder known as Beta-propeller Protein Associated Neurodegeneration (BPAN). Herein we describe the case of a 4-year-old girl with 2 episodes of febrile seizures, a brain MRI showing nonspecific hyperintense signal in the dentate nucleus area, and delays in language and communication development. Her diagnosis was made based on a genetic evaluation where exome sequencing revealed a mutation in the position chrX:48.933.022 region of the WDR45 gene. The literature describes different clinical presentations for BPAN, each with a different prognosis, suggesting a wide range of possible symptoms of BPAN, including mild cognitive delay and even epileptic encephalopathy (EE). (AU)

Is there heart disease in cases of neurodegeneration associated with mutations in C19orf12?

INTRODUCTION: In mitochondrial membrane protein-associated neurodegeneration (MPAN), a subtype of neurodegeneration with brain iron accumulation (NBIA), patients suffer from optic nerve atrophy and dementia, which are also typical for another group of diseases, the mitochondrial diseases (MD). Around 30% of patients with MD have heart disease, commonly cardiomyopathy and arrhythmias, and 10% experience a major adverse cardiovascular event. The aim of this study was to assess cardiac involvement in MPAN. METHODS: Thirteen patients with MPAN were evaluated after written informed consent. All patients had echocardiography and 12 patients had 24-h Holter electrocardiogram (ECG) monitoring using 3-channel digital recorders. RESULTS: Echocardiography revealed normal values for the dimensions of all heart chambers. The systolic function of the left ventricle was normal in all cases. Right ventricle systolic impairment was found in three patients. 24-hour Holter ECG revealed predominant resting tachycardia during daytime with no physiological slowing of heart rate during sleep in seven cases. No significant arrhythmias were found. In nine patients, selected heart rate variability (HRV) parameters were lower than reference values. CONCLUSION: Cardiomyopathy, typical of MD, was not found in patients with MPAN. There were no significant arrhythmias, but disturbances in the circadian rhythm of the heart rate were observed in most cases. The decrease in HRV may reflect an early sign of autonomic dysfunction. A standard cardiac work-up is recommended for patients with MPAN to assess if additional treatment is needed.

The infantile neuroaxonal dystrophy rating scale (INAD-RS).

BACKGROUND: INAD is an autosomal recessive neurogenetic disorder caused by biallelic pathogenic variants in PLA2G6. The downstream enzyme, iPLA2, plays a critical role in cell membrane homeostasis by helping to regulate levels of phospholipids. The clinical presentation occurs between 6 months and 3 years with global developmental regression, hypotonia, and progressive spastic tetraparesis. Progression is often rapid, resulting in severe spasticity, visual impairment, and cognitive decline, with many children not surviving past the first decade of life. To date, no accepted tool for assessing the severity of INAD exists; other commonly used scales (e.g. CHOP-INTEND, Modified Ashworth, Hammersmith Functional Motor Scale) do not accurately gauge the current severity of INAD, nor are they sensitive/specific enough to monitor disease progression. Finally, these other scales are not appropriate, because they do not address the combination of CNS, peripheral nerve, and visual pathology that occurs in children with INAD. METHODS: We have developed and validated a structured neurological examination for INAD (scored out of 80). The examination includes six main categories of pediatric developmental evaluation: 1) gross motor-and-truncal-stability skills, 2) fine motor skills, 3) bulbar function, 4) ocular function, 5) temporo-frontal function, and, 6) Functional evaluation of the autonomic nervous system. A cohort of patients diagnosed with INAD were followed prospectively to validate the score against disease severity and disease progression. RESULTS: We show significant correlation between the total neurological assessment score and months since symptom onset with a statistically significant (p = 6.7 × 10- 07) correlation between assessment score and disease onset. As hypothesized, the coefficient of months-since-symptom-onset is strongly negative, indicating a negative correlation between total score and months since symptom onset. CONCLUSION: We have developed and validated a novel neurological assessment score in INAD that demonstrates strong correlation with disease severity and disease progression.

Investigations of Huntington's Disease and Huntington's Disease-Like Syndromes in Indian Choreatic Patients.

BACKGROUND: The diagnostic workup for choreiform movement disorders including Huntington's disease (HD) and those mimicking HD like phenotype is complex. OBJECTIVE: The aim of the present study was to genetically define HD and HD-like presentations in an Indian cohort. We also describe HTT-CAG expansion manifesting as neuroferritinopathy-like disorder in four families from Punjab in India. MATERIALS AND METHODS: 159 patients clinically diagnosed as HD and HD-like presentations from various tertiary neurology clinics were referred to our centre (CSIR-IGIB) for genetic investigations. As a first tier test, CAG-TNR for HTT was performed and subsequently HD-negative samples were screened for JPH3 (HDL2), TBP (SCA17), ATN1 (DRPLA), PPP2R2B (SCA12) and GGGGCC expansion in C9orf72 gene. Four families presenting as neuroferritinopathy-like disorder were also investigated for HTT-CAG expansion. RESULTS: 94 of 159 (59%) patients were found to have expanded HTT-CAG repeats. Pathogenic repeat expansion in JPH3, TBP, ATN1 and C9orf72 were not found in HD negative cases. Two patients were positive for SCA12-CAG expansion in pathogenic length, whereas 5 cases harboured TBP-CAG repeats falling in reduced penetrance range of 41- 48 repeats for SCA17. Four unrelated families, presented with atypical chorea and brain MRI findings suggestive of basal ganglia abnormalities mimicking neuroferritinopathy were found to harbour HTT-CAG expansion. CONCLUSION: We present SCA12 as a new reported phenocopy of HD which should be considered for diagnostic workout along with SCA17 for HD-like syndromes. This study also illustrates the necessity, to consider evolving HD like phenotype, as a clinical diagnosis for cases with initial manifestations depicting neuroferritinopathy.

Differential levels of Neurofilament Light protein in cerebrospinal fluid in patients with a wide range of neurodegenerative disorders.

Cerebrospinal fluid (CSF) biomarkers are useful in the diagnosis and the prediction of progression of several neurodegenerative diseases. Among them, CSF neurofilament light (NfL) protein has particular interest, as its levels reflect neuroaxonal degeneration, a common feature in various neurodegenerative diseases. In the present study, we analyzed NfL levels in the CSF of 535 participants of the SPIN (Sant Pau Initiative on Neurodegeneration) cohort including cognitively normal participants, patients with Alzheimer disease (AD), Down syndrome (DS), frontotemporal dementia (FTD), amyotrophic lateral sclerosis (ALS), dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS). We evaluated the differences in CSF NfL accross groups and its association with other CSF biomarkers and with cognitive scales. All neurogenerative diseases showed increased levels of CSF NfL, with the highest levels in patients with ALS, FTD, CBS and PSP. Furthermore, we found an association of CSF NfL levels with cognitive impairment in patients within the AD and FTD spectrum and with AD pathology in DLB and DS patients. These results have implications for the use of NfL as a marker in neurodegenerative diseases.

Phenotypic and Imaging Spectrum Associated With WDR45.

BACKGROUND: Mutations in the X-linked gene WDR45 cause neurodegeneration with brain iron accumulation type 5. Global developmental delay occurs at an early age with slow progression to dystonia, parkinsonism, and dementia due to progressive iron accumulation in the brain. METHODS: We present 17 new cases and reviewed 106 reported cases of neurodegeneration with brain iron accumulation type 5. Detailed information related to developmental history and key time to event measures was collected. RESULTS: Within this cohort, there were 19 males. Most individuals were molecularly diagnosed by whole-exome testing. Overall 10 novel variants were identified across 11 subjects. All individuals were affected by developmental delay, most prominently in verbal skills. Most individuals experienced a decline in motor and cognitive skills. Although most individuals were affected by seizures, the spectrum ranged from provoked seizures to intractable epilepsy. The imaging findings varied as well, often evolving over time. The classic iron accumulation in the globus pallidus and substantia nigra was noted in half of our cohort and was associated with older age of image acquisition, whereas myelination abnormalities were associated with younger age. CONCLUSIONS: WDR45 mutations lead to a progressive and evolving disorder whose diagnosis is often delayed. Developmental delay and seizures predominate in early childhood, followed by a progressive decline of neurological function. There is variable expressivity in the clinical phenotypes of individuals with WDR45 mutations, suggesting that this gene should be considered in the diagnostic evaluation of children with myelination abnormalities, iron deposition, developmental delay, and epilepsy depending on the age at evaluation.

Early-onset presentation of a new subtype of ß-Propeller protein-associated neurodegeneration (BPAN) caused by a de novo WDR45 deletion in a 6 year-old female patient.

Neurodegeneration with brain iron accumulation (NBIA) comprises a group of rare genetic disorders characterized by progressive extrapyramidal and other neurological symptoms due to focal iron accumulation in the basal ganglia (Adidi et al., 2016). ß-Propeller protein-associated neurodegeneration (BPAN) is the most recently identified subtype of NBIA caused by heterozygous variants in WDR45 (OMIM: *300526) at Xp11.23. We report the clinical neurophysiological and neuro-imaging findings of a new subtype of BPAN in a 6 year-old female patient, who was identified to have a large de novo WDR45 deletion who presented in the first year of life with early onset global developmental delay, severe cognitive impairment, generalized hypotonia and a corticosteroid responsive epileptic encephalopathy.

Childhood Dystonia-Parkinsonism Following Infantile Spasms-Clinical Clue to Diagnosis in Early Beta-Propeller Protein-Associated Neurodegeneration.

INTRODUCTION: Beta-propeller protein-associated neurodegeneration (BPAN) is a very rare, X-linked dominant (XLD) inherited member of the neurodegeneration with brain iron accumulation (NBIA) disease family. CASE REPORT: We present a female case of BPAN with infantile spasms in the first year, Rett-like symptomatology, focal epilepsy, and loss of motor skills in childhood. Menarche occurred at the age of 9, after precocious pubarche and puberty.Dystonia-parkinsonism as extrapyramidal sign at the age of 10 years resulted in radiological and genetic work-up. RESULTS: Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) measured 66/120 points in body part-related dystonia symptoms. Cerebrospinal fluid examination showed dopamine depletion.T2 and B0 sequences of the diffusion-weighted magnetic resonance imaging showed susceptibility artifacts with NBIA-typical hypointense globus pallidus (GP) and substantia nigra (SN). Next-generation sequencing revealed a BPAN-causing pathogenic variant in WDR45 (WD repeat-containing protein 45) gene (c.830 + 1G > A, XLD, heterozygous, de novo). Skewed X-inactivation was measured (2:98). CONCLUSIONS: Autophagy-related X-linked BPAN disease might still be underdiagnosed in female cases of infantile spasms.Skewed X-inactivation will have mainly influenced the uncommon, very early childhood neurodegenerative symptomatology in the present BPAN case. Oral levodopa substitution led to improvement in sleep disorder, hypersalivation, and swallowing.Reduced white matter and hypointense signals in SN and GP on susceptibility sequences in magnetic resonance imaging are characteristic radiological findings of advanced disease in NBIA. No BPAN-typical halo sign in T1-weighted scan at midbrain level was seen at the age of 11 years. NBIA panel is recommended for early diagnosis.

Neurodegeneration with Brain Iron Accumulation: Two Additional Cases with Dystonic Opisthotonus.

Background: Specific phenomenology and pattern of involvement in movement disorders point toward a probable clinical diagnosis. For example, forehead chorea usually suggests Huntington's disease; feeding dystonia suggests neuroacanthocytosis and risus sardonicus is commonly seen in Wilson's disease. Dystonic opisthotonus has been described as a characteristic feature of neurodegeneration with brain iron accumulation (NBIA) related to PANK2 and PLA2G6 mutations. Case report: We describe two additional patients in their 30s with severe extensor truncal dystonia causing opisthotonic posturing in whom evaluation revealed the diagnosis of NBIA confirmed by genetic testing. Discussion: Dystonic opisthotonus may be more common in NBIA than it is reported and its presence especially in a young patient should alert the neurologists to a possibility of probable NBIA.

Neuroaxonal Dystrophy in a mule: first case reported / Distrofia neuroaxonal em muar: primeiro relato de caso

A 12-month-old mule (sterile hybrid equine species) presented unspecific neurological changes (symmetric ataxia, dysmetria, conscious proprioceptive deficit and weakness). Due to poor prognosis and to the fact that a sibling from the previous generation exhibited similar clinical signs that were not definitively diagnosed, the animal was euthanized. Diagnosis of neuroaxonal dystrophy was confirmed by anatomohistopathological analysis. This is the first clinical case of neuronal dystrophy in a mule reported in the world. The clinical and histopathological characteristics of this disease were very similar to those reported for several equine breeds. Therefore, the disease should also be considered in the diagnosis of neurological conditions in mules and donkeys.(AU)

Relata-se o caso de uma mula de 12 meses que apresentou alterações neurológicas inespecíficas (ataxia simétrica, dismetria, déficit proprioceptivo consciente e fraqueza). Devido ao mau prognóstico e ao fato de um irmão da geração anterior apresentar sinais clínicos similares sem diagnóstico conclusivo, o animal foi eutanasiado. O diagnóstico de distrofia neuroaxonal foi confirmado por análise anátomo-histopatológica. Esse é o primeiro caso clínico de distrofia neuroaxonal em muar relatado no mundo. As características clínicas e histopatológicas dessa doença foram muito semelhantes às relatadas em várias raças de equinos. Portanto, a doença também deve ser considerada no diagnóstico de condições neurológicas em muares e asininos.(AU)