Brazilian consensus recommendations on the diagnosis and treatment of autoimmune encephalitis in the adult and pediatric populations.

BACKGROUND: Autoimmune encephalitis (AIE) is a group of inflammatory diseases characterized by the presence of antibodies against neuronal and glial antigens, leading to subacute psychiatric symptoms, memory complaints, and movement disorders. The patients are predominantly young, and delays in treatment are associated with worse prognosis. OBJECTIVE: With the support of the Brazilian Academy of Neurology (Academia Brasileira de Neurologia, ABN) and the Brazilian Society of Child Neurology (Sociedade Brasileira de Neurologia Infantil, SBNI), a consensus on the diagnosis and treatment of AIE in Brazil was developed using the Delphi method. METHODS: A total of 25 panelists, including adult and child neurologists, participated in the study. RESULTS: The panelists agreed that patients fulfilling criteria for possible AIE should be screened for antineuronal antibodies in the serum and cerebrospinal fluid (CSF) using the tissue-based assay (TBA) and cell-based assay (CBA) techniques. Children should also be screened for anti-myelin oligodendrocyte glucoprotein antibodies (anti-MOG). Treatment should be started within the first 4 weeks of symptoms. The first-line option is methylprednisolone plus intravenous immunoglobulin (IVIG) or plasmapheresis, the second-line includes rituximab and/or cyclophosphamide, while third-line treatment options are bortezomib and tocilizumab. Most seizures in AIE are symptomatic, and antiseizure medications may be weaned after the acute stage. In anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis, the panelists have agreed that oral immunosuppressant agents should not be used. Patients should be evaluated at the acute and postacute stages using functional and cognitive scales, such as the Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), the Modified Rankin Scale (mRS), and the Clinical Assessment Scale in Autoimmune Encephalitis (CASE). CONCLUSION: The present study provides tangible evidence for the effective management of AIE patients within the Brazilian healthcare system.

ANTECEDENTES: Encefalites autoimunes (EAIs) são um grupo de doenças inflamatórias caracterizadas pela presença de anticorpos contra antígenos neuronais e gliais, que ocasionam sintomas psiquiátricos subagudos, queixas de memória e distúrbios anormais do movimento. A maioria dos pacientes é jovem, e o atraso no tratamento está associado a pior prognóstico. OBJETIVO: Com o apoio da Academia Brasileira de Neurologia (ABN) e da Sociedade Brasileira de Neurologia Infantil (SBNI), desenvolvemos um consenso sobre o diagnóstico e o tratamento da EAIs no Brasil utilizando a metodologia Delphi. MéTODOS: Um total de 25 especialistas, incluindo neurologistas e neurologistas infantis, foram convidados a participar. RESULTADOS: Os especialistas concordaram que os pacientes com critérios de possíveis EAIs devem ser submetidos ao rastreio de anticorpos antineuronais no soro e no líquido cefalorraquidiano (LCR) por meio das técnicas de ensaio baseado em tecidos (tissue-based assay, TBA, em inglês) e ensaio baseado em células (cell-based assay, CBA, em inglês). As crianças também devem ser submetidas ao rastreio de de anticorpo contra a glicoproteína da mielina de oligodendrócitos (anti-myelin oligodendrocyte glycoprotein, anti-MOG, em inglês). O tratamento deve ser iniciado dentro das primeiras 4 semanas dos sintomas, sendo as opções de primeira linha metilprednisolona combinada com imunoglobulina intravenosa (IGIV) ou plasmaférese. O tratamento de segunda linha inclui rituximabe e ciclofosfamida. Bortezomib e tocilizumab são opções de tratamento de terceira linha. A maioria das crises epilépticas nas EAIs são sintomáticas, e os fármacos anticrise podem ser desmamadas após a fase aguda. Em relação à encefalite antirreceptor de N-metil-D-aspartato (anti-N-methyl-D-aspartate receptor, anti-NMDAR, em inglês), os especialistas concordaram que agentes imunossupressores orais não devem ser usados. Os pacientes devem ser avaliados na fase aguda e pós-aguda mediante escalas funcionais e cognitivas, como Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Modified Rankin Scale (mRS), e Clinical Assessment Scale in Autoimmune Encephalitis (CASE). CONCLUSãO: Esta pesquisa oferece evidências tangíveis do manejo efetivo de pacientes com EAIs no sistema de saúde Brasileiro.

Young-Onset Alzheimer Dementia Due to a Novel Pathogenic Presenilin 1 Variant Initially Misdiagnosed as Autoimmune Encephalitis.

OBJECTIVES: Pathogenic variants in presenilin 1 (PSEN1) are related to early-onset Alzheimer disease (AD) and may occur as de novo variants. In comparison with sporadic forms, it can present with psychiatric manifestations, seizures, myoclonus, and focal presentation. Because PSEN1 can occur in young patients who lack a family history of neurologic disorders and because these symptoms are also frequent in autoimmune encephalitis (AE), diagnosis may be overlooked. Our aim was to demonstrate the challenge in diagnosing young patients with neurodegenerative diseases that simulate AE. METHODS: We describe a case of a young patient with insidious progressive dementia, myoclonus, seizures, and aphasia, with no family history of dementia, along with signs suggestive of neuroinflammation on brain MRI and CSF examination. RESULTS: She was initially misdiagnosed as having AE. Further investigation was performed, leading to the discovery of a novel and de novo pathogenic variant in PSEN1. DISCUSSION: This case demonstrates the importance of considering PSEN1 in young patients with insidious progressive dementia with atypical clinical and neuroimaging features, even in patients without a family history of neurologic disorders. Not adhering to published criteria of possible and probable AE and overinterpretation of subtle inflammatory findings in CSF and MRI contribute to misdiagnosis.

Myoclonus improvement after seizures in progressive myoclonic epilepsy type 7: a case report.

BACKGROUND: Progressive Myoclonic Epilepsy (PME) is a group of rare diseases that are difficult to differentiate from one another based on phenotypical characteristics. CASE REPORT: We report a case of PME type 7 due to a pathogenic variant in KCNC1 with myoclonus improvement after epileptic seizures. DISCUSSION: Myoclonus improvement after seizures may be a clue to the diagnosis of Progressive Myoclonic Epilepsy type 7.

Identifying high-risk neurological phenotypes in adult-onset classic monogenic autoinflammatory diseases: when should neurologists consider testing?

BACKGROUND: Monogenic autoinflammatory disorders result in a diverse range of neurological symptoms in adults, often leading to diagnostic delays. Despite the significance of early detection for effective treatment, the neurological manifestations of these disorders remain inadequately recognized. METHODS: We conducted a systematic review searching Pubmed, Embase and Scopus for case reports and case series related to neurological manifestations in adult-onset monogenic autoinflammatory diseases. Selection criteria focused on the four most relevant adult-onset autoinflammatory diseases-deficiency of deaminase 2 (DADA2), tumor necrosis factor receptor associated periodic fever syndrome (TRAPS), cryopyrin associated periodic fever syndrome (CAPS), and familial mediterranean fever (FMF). We extracted clinical, laboratory and radiological features to propose the most common neurological phenotypes. RESULTS: From 276 records, 28 articles were included. The median patient age was 38, with neurological symptoms appearing after a median disease duration of 5 years. Headaches, cranial nerve dysfunction, seizures, and focal neurological deficits were prevalent. Predominant phenotypes included stroke for DADA2 patients, demyelinating lesions and meningitis for FMF, and meningitis for CAPS. TRAPS had insufficient data for adequate phenotype characterization. CONCLUSION: Neurologists should be proactive in diagnosing monogenic autoinflammatory diseases in young adults showcasing clinical and laboratory indications of inflammation, especially when symptoms align with recurrent or chronic meningitis, small vessel disease strokes, and demyelinating lesions.

Editorial for Brain Sciences Special Issue: "Neurogenetic Disorders across Human Life: From Infancy to Adulthood".

This Special Issue assembles papers that highlight different types of neurogenetic disorders that occur throughout human life, from childhood to adulthood, focusing on their natural history, epidemiology, diagnosis, and treatment approaches [...].

Peculiar aetiology for orbital apex syndrome: Wyburn-Mason syndrome as orbital apex lesion.

Background: Wyburn-Mason syndrome is a rare, non-hereditary congenital disease, belonging to the group of neurocutaneous syndromes with fewer than 100 cases reported since its first description in 1937. Case report: A young adult man was initially evaluated at the age of 2 years for proptosis and progressive visual impairment of the right eye, followed by impairment in ocular abduction, adduction and elevation as well as amaurosis. MRI revealed an expansive formation centred in the right orbit compromising conal spaces with distortion of eye muscles and optic nerve. The lesion extended through the superior orbital fissure into the right cavernous sinus and to the contralateral orbit. Despite embolisation, proptosis and oedema of the periorbital tissue continued to worsen. The combination of facial, ocular and intracranial vascular malformations and the exclusion of alternative aetiologies led to a diagnosis of cerebrofacial arteriovenous metameric syndrome (CAMS) 1 (Wyburn-Mason syndrome). Discussion: Important differential diagnoses are other CAMS, such as Sturge-Weber syndrome, as well as other conditions such as retinal cavernous haemangioma and vasoproliferative tumours. The optimal treatment regimen for severe cases of this syndrome is still unclear. Wyburn-Mason syndrome should be considered in patients presenting multiple arteriovenous malformations with orbital apex lesions.

Spinocerebellar ataxia type 2 has multiple ancestral origins.

INTRODUCTION: Spinocerebellar ataxia type 2 (SCA2) is a dominant neurodegenerative disorder due to expansions of a CAG repeat tract (CAGexp) at the ATXN2 gene. Previous studies found only one ancestral haplotype worldwide, with a C allele at rs695871. This homogeneity was unexpected, given the severe anticipations related to SCA2. We aimed to describe informative ancestral haplotypes found in South American SCA2 families. METHODS: Seventy-seven SCA2 index cases were recruited from Brazil, Peru, and Uruguay; 263 normal chromosomes were used as controls. The SNPs rs9300319, rs3809274, rs695871, rs1236900 and rs593226, and the STRs D12S1329, D12S1333, D12S1672 and D12S1332, were used to reconstruct haplotypes. RESULTS: Eleven ancestral haplotypes were found in SCA2 families. The most frequent ones were A-G-C-C-C (46.7 % of families), G-C-C-C-C (24.6 %) and A-C-C-C-C (10.3 %) and their mean (sd) CAGexp were 41.68 (3.55), 40.42 (4.11) and 45.67 (9.70) (p = 0.055), respectively. In contrast, the mean (sd) CAG lengths at normal alleles grouped per haplotypes G-C-G-A-T, A-G-C-C-C and G-C-C-C-C were 22.97 (3.93), 23.85 (3.59), and 30.81 (4.27) (p < 0.001), respectively. The other SCA2 haplotypes were rare: among them, a G-C-G-A-T lineage was found, evidencing a G allele in rs695871. CONCLUSION: We identified several distinct ancestral haplotypes in SCA2 families, including an unexpected lineage with a G allele at rs695871, a variation never found in hundreds of SCA2 patients studied worldwide. SCA2 has multiple origins in South America, and more studies should be done in other regions of the world.

Expanding the phenotypic spectrum of CLCN2-related leucoencephalopathy and ataxia.

Mutations in CLCN2 are a rare cause of autosomal recessive leucoencephalopathy with ataxia and specific imaging abnormalities. Very few cases have been reported to date. Here, we describe the clinical and imaging phenotype of 12 additional CLCN2 patients and expand the known phenotypic spectrum of this disorder. Informed consent was obtained for all patients. Patients underwent either whole-exome sequencing or focused/panel-based sequencing to identify variants. Twelve patients with biallelic CLCN2 variants are described. This includes three novel likely pathogenic missense variants. All patients demonstrated typical MRI changes, including hyperintensity on T2-weighted images in the posterior limbs of the internal capsules, midbrain cerebral peduncles, middle cerebellar peduncles and cerebral white matter. Clinical features included a variable combination of ataxia, headache, spasticity, seizures and other symptoms with a broad range of age of onset. This report is now the largest case series of patients with CLCN2-related leucoencephalopathy and reinforces the finding that, although the imaging appearance is uniform, the phenotypic expression of this disorder is highly heterogeneous. Our findings expand the phenotypic spectrum of CLCN2-related leucoencephalopathy by adding prominent seizures, severe spastic paraplegia and developmental delay.

Pompe disease misdiagnosed as polymyositis.

Late-onset Pompe disease manifests predominantly in the proximal lower limbs and may be mistaken for an inflammatory myopathy. A 46-year-old man with acromegaly had an 8-year history of progressive weakness. His myopathy was initially attributed to the acromegaly, but severe progression prompted a muscle biopsy, which suggested an inflammatory myopathy. However, his weakness progressed despite treatment for polymyositis. His muscle ultrasound scan pattern was more suggestive of Pompe disease than polymyositis, and Pompe disease was confirmed by genetic and enzymatic testing. Patients with apparent polymyositis, which persists despite treatment, require reconsideration of the diagnosis, with particular attention to treatable genetic causes.

Marked neuropsychiatric involvement and dysmorphic features in nemaline myopathy.

BACKGROUND: Inherited nemaline myopathy is one of the most common congenital myopathies. This genetically heterogeneous disease is defined by the presence of nemaline bodies in muscle biopsy. The phenotypic spectrum is wide and cognitive involvement has been reported, although not extensively evaluated. METHODS: We report two nemaline myopathy patients presenting pronounced central nervous system involvement leading to functional compromise and novel facial and skeletal dysmorphic findings, possibly expanding the disease phenotype. RESULTS: One patient had two likely pathogenic NEB variants, c.2943G > A and c.8889 + 1G > A, and presented cognitive impairment and dysmorphic features, and the other had one pathogenic variant in ACTA1, c.169G > C (p.Gly57Arg), presenting autism spectrum disorder and corpus callosum atrophy. Both patients had severe cognitive involvement despite milder motor dysfunction. CONCLUSION: We raise the need for further studies regarding the role of thin filament proteins in the central nervous system and for a systematic cognitive assessment of congenital myopathy patients.

Correlation between ABO blood type, susceptibility to SARS-CoV-2 infection and COVID-19 disease severity: A systematic review

ABSTRACT Objectives: To verify the association between the ABO blood type and the risk of SARS-CoV-2 infection and COVID-19 disease severity. Methods: This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), using the 2020 PRISMA Checklist and flow diagram, and articles selected for review were analyzed using the Newcastle-Ottawa Quality Rating Scale. The research question was: "Would the ABO blood group influence the risk of infection and clinical course of patients infected with SARS-CoV-2?", The following databases were used: Embase, PubMed, Virtual Health Library (VHL), Web of Science, Science-Direct and Scopus. The protocol for this review was registered in the Prospective Register of Systematic Reviews (PROSPERO), number CRD42021245945. Results: We found 798 articles across PubMed, Embase, Scopus, Web of Science, Science Direct and Virtual Health Library and 54 articles were included in the final analysis. Among 30 studies evaluating the risk of COVID-19 infection, 21 found significant correlations with ABO blood groups, 14 of them revealing an increased risk in blood group A and 15 studies showing a decreased risk in blood group O. Most studies found no significant correlation with disease severity or mortality. Conclusion: The qualitative assessment of available information suggests that blood group A may be a risk factor for COVID-19 infection and that blood group O may have a protective effect. We were unable to determine a clear association between the ABO blood group and mortality. These conclusions are based on highly heterogenous evidence.

Higher Prevalence of Nonsense Pathogenic DMD Variants in a Single-Center Cohort from Brazil: A Genetic Profile Study That May Guide the Choice of Disease-Modifying Treatments.

Dystrophinopathies are muscle diseases caused by pathogenic variants in DMD, the largest gene described in humans, representing a spectrum of diseases ranging from asymptomatic creatine phosphokinase elevation to severe Duchenne muscular dystrophy (DMD). Several therapeutic strategies are currently in use or under development, each targeting different pathogenic variants. However, little is known about the genetic profiles of northeast Brazilian patients with dystrophinopathies. We describe the spectrum of pathogenic DMD variants in a single center in northeast Brazil. This is an observational, cross-sectional study carried out through molecular-genetic analysis of male patients diagnosed with dystrophinopathies using Multiplex Ligation-dependent Probe Amplification (MLPA) followed by Next-Generation Sequencing (NGS)-based strategies. A total of 94 male patients were evaluated. Deletions (43.6%) and duplications (10.6%) were the most recurring patterns of pathogenic variants. However, small variants were present in 47.1% of patients, most of them nonsense variants (27.6%). This is the largest South American single-center case series of dystrophinopathies to date. We found a higher frequency of treatment-amenable nonsense single-nucleotide variants than most previous studies. These findings may have implications for diagnostic strategies in less-known populations, as a higher frequency of nonsense variants may mean a higher possibility of treating patients with disease-modifying drugs.

Brazilian autoimmune encephalitis network (BrAIN): antibody profile and clinical characteristics from a multicenter study.

Background: The frequency of antibodies in autoimmune encephalitis (AIE) may vary in different populations, however, data from developing countries are lacking. To describe the clinical profile of AIE in Brazil, and to evaluate seasonality and predictors of AIE in adult and pediatric patients. Methods: We evaluated patients with possible AIE from 17 centers of the Brazilian Autoimmune Encephalitis Network (BrAIN) between 2018 and 2022. CSF and serum were tested with TBAs and CBAs. Data on clinical presentation, complementary investigation, and treatment were compiled. Seasonality and predictors of AIE in adult and pediatric populations were analyzed. Results: Of the 564 patients, 145 (25.7%) were confirmed as seropositive, 69 (12.23%) were seronegative according to Graus, and 58% received immunotherapy. The median delay to diagnosis confirmation was 5.97 ± 10.3 months. No seasonality variation was observed after 55 months of enrolment. The following antibodies were found: anti-NMDAR (n=79, 54%), anti-MOG (n=14, 9%), anti-LGI1(n=12, 8%), anti-GAD (n=11, 7%), anti-GlyR (n=7, 4%), anti-Caspr2 (n=6, 4%), anti-AMPAR (n=4, 2%), anti-GABA-BR (n=4, 2%), anti-GABA-AR (n=2, 1%), anti-IgLON5 (n=1, 1%), and others (n=5, 3%). Predictors of seropositive AIE in the pediatric population (n=42) were decreased level of consciousness (p=0.04), and chorea (p=0.002). Among adults (n=103), predictors of seropositive AIE were movement disorders (p=0.0001), seizures (p=0.0001), autonomic instability (p=0.026), and memory impairment (p=0.001). Conclusion: Most common antibodies in Brazilian patients are anti-NMDAR, followed by anti-MOG and anti-LGI1. Only 26% of the possible AIE patients harbor antibodies, and 12% were seronegative AIE. Patients had a 6-month delay in diagnosis and no seasonality was found. Findings highlight the barriers to treating AIE in developing countries and indicate an opportunity for cost-effect analysis. In this scenario, some clinical manifestations help predict seropositive AIE such as decreased level of consciousness, chorea, and dystonia among children, and movement disorders and memory impairment among adults.

Bailey-Bloch Congenital Myopathy in Brazilian Patients: A Very Rare Myopathy with Malignant Hyperthermia Susceptibility.

BACKGROUND: Congenital myopathy-13 (CMYP13), also known as Bailey-Bloch congenital myopathy and Native American myopathy (NAM), is a condition caused by biallelic missense pathogenic variants in STAC3, which encodes an important protein necessary for the excitation-relaxation coupling machinery in the muscle. Patients with biallelic pathogenic variants in STAC3 often present with congenital weakness and arthrogryposis, cleft palate, ptosis, myopathic facies, short stature, kyphoscoliosis, and susceptibility to malignant hyperthermia provoked by anesthesia. We present two unrelated cases of Bailey-Bloch congenital myopathy descendants of non-consanguineous parents, which were investigated for delayed psychomotor development and generalized weakness. To the best of our knowledge, these are the first descriptions of CMYP13 in Brazil. In both patients, we found the previously described pathogenic missense variant p.Trp284Ser in homozygosity. CONCLUSION: We seek to highlight the need for screening for CMYP13 in patients expressing the typical phenotype of the disease even in the absence of Lumbee Native American ancestry, and to raise awareness to possible complications like malignant hyperthermia in Bailey-Bloch congenital myopathy.

Supratentorial Lymphocytic Inflammation with Parenchymal Perivascular Enhancement Responsive to Steroids (SLIPPERS)-Does it Really Exist?

Supratentorial Lymphocytic Inflammation with Parenchymal Perivascular Enhancement Responsive to Steroids (SLIPPERS) is a rare variant of the CLIPPERS spectrum with less than ten reports published so far. There is ongoing discussion regarding whether SLIPPERS is a disease entity on its own or just an acronym encompassing many underlying diagnoses, such as sarcoidosis, vasculitis and anti-glial fibrillary acidic protein (GFAP)-associated disease. A 40-year-old woman presented with episodes of language and attention impairment. Magnetic resonance imaging (MRI) revealed T2/FLAIR hyperintense lesions in the subcortical white matter associated with a micronodular, curvilinear perivascular contrast-enhancement. Alternative diagnoses were excluded. There was a remarkable response to steroids. A relapse occurred after six years, and the biopsy showed perivascular T-cell lymphocytic infiltrate, without granulomas, vasculitis, or neoplasia. There was complete resolution of the relapse after steroids. This case represents the longest reported follow-up of a patient diagnosed with SLIPPERS, and brain biopsy after 6 years did not suggest alternative diagnoses. This report contributes to the discussion regarding the possibility that exclusive supratentorial CLIPPERS-like pathology might be an isolated disease entity, but more biopsy-proven cases with a longer follow-up are needed to support this hypothesis. Recently, GFAP astrocytopathy has been characterized and might correspond to a significant number of cases previously diagnosed as CLIPPERS or SLIPPERS.

Controversies in immunotherapy for anti-NMDA receptor encephalitis: a scoping review with a proposal of operational definitions.

Anti-NMDA receptor encephalitis (NMDARE), an autoimmune encephalitis associated with autoantibodies against the N-methyl-D-aspartate (NMDA) receptor, affects predominantly young women and is associated with psychiatric symptoms, seizures, movement disorders, and autonomic instability. Traditional treatments of anti-NMDA receptor encephalitis involve corticosteroids, intravenous immunoglobulin, plasmapheresis, cyclophosphamide, and rituximab. However, many controversies remain in the treatment for NMDA receptor encephalitis, such as optimal timing and combination of different immunotherapies, the role of newer strategies (e.g., bortezomib or tocilizumab) for severe and refractory patients, and the need or not for long-term immunosuppression. Our goal was to perform a scoping review to discuss the controversial topics of immunotherapy for NMDA receptor encephalitis and propose operational definitions to guide clinical practice and future research in the field.

Pathophysiology and Treatment of Lipid Abnormalities in Cerebrotendinous Xanthomatosis: An Integrative Review.

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive disorder caused by pathogenic variants in CYP27A1, leading to a deficiency in sterol 27-hydroxylase. This defect results in the accumulation of cholestanol and bile alcohols in various tissues, including the brain, tendons and peripheral nerves. We conducted this review to evaluate lipid profile abnormalities in patients with CTX. A search was conducted in PubMed, Embase and the Virtual Health Library in January 2023 to evaluate studies reporting the lipid profiles of CTX patients, including the levels of cholestanol, cholesterol and other lipids. Elevated levels of cholestanol were consistently observed. Most patients presented normal or low serum cholesterol levels. A decrease in chenodeoxycholic acid (CDCA) leads to increased synthesis of cholesterol metabolites, such as bile alcohols 23S-pentol and 25-tetrol 3-glucuronide, which may serve as surrogate follow-up markers in patients with CTX. Lipid abnormalities in CTX have clinical implications. Cholestanol deposition in tissues contributes to clinical manifestations, including neurological symptoms and tendon xanthomas. Dyslipidemia and abnormal cholesterol metabolism may also contribute to the increased risk of atherosclerosis and cardiovascular complications observed in some CTX patients.

Neuropsychological Characterization of Autosomal Recessive Intellectual Developmental Disorder 59 Associated with IMPA1 (MRT59).

Biallelic loss of function of IMPA1 causes autosomal recessive intellectual developmental disorder 59 (MRT59, OMIM #617323). MRT59 has been reported to present with significant intellectual disability and disruptive behavior, but little is known about the neurocognitive pattern of those patients. Thus, the aims of this study were: (1) to assess the cognitive profile of these patients, and (2) to evaluate their functional dependence levels. Eighteen adults, aged 37 to 89 years, participated in this study: nine MRT59 patients, five heterozygous carriers and four non-carrier family members. All of them were from a consanguineous family living in Northeast Brazil. All IMPA1 patients had the (c.489_493dupGGGCT) pathogenic variant in homozygosis. For cognitive assessment, the WASI battery was applied in nine MRT59 patients and compared to heterozygous carriers and non-carrier family members. Functional dependence was evaluated using the functional independence measure (FIM). Patients showed moderate to severe intellectual disability and severe functional disabilities. Heterozygous carriers did not differ from non-carriers. MRT59 patients should be followed up by health professionals in an interdisciplinary way to understand their cognitive disabilities and functional needs properly.