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Background: Genetic underpinnings in Parkinson's disease (PD) and parkinsonian syndromes are challenging, and recent discoveries regarding their genetic pathways have led to potential gene-specific treatment trials., Cases: We report 3 X-linked levodopa (l-dopa)-responsive parkinsonism-epilepsy syndrome cases due to a hemizygous variant in the phosphoglycerate kinase 1 (PGK1) gene. The likely pathogenic variant NM_000291.4 (PGK1):c.950G > A;p.(Gly317Asp) was identified in a hemizygous state., Literature Review: Only 8 previous cases have linked this phenotype to PGK1, a gene more commonly associated with hemolytic anemia and myopathy. The unusual association of epilepsy, psychiatric symptoms, action tremor, limb dystonia, cognitive symptoms, and l-dopa-responsive parkinsonism must draw attention to PGK1 mutations, especially because this gene is absent from most commercial hereditary parkinsonism panels., Conclusions: This report aims to shed light on an overlooked gene that causes hereditary parkinsonian syndromes. Further research regarding genetic pathways in PD may provide a better understanding of its pathophysiology and open possibilities for new disease-modifying trials, such as SNCA, LRRK2, PRKN, PINK1, and DJ-1 genes., (© 2024 International Parkinson and Movement Disorder Society.)

Background: Genetic prion diseases, including Gerstmann-Sträussler-Scheinker disease (GSS), are extremely rare, fatal neurodegenerative disorders, often associated with progressive ataxia and cognitive/neuropsychiatric symptoms. GSS typically presents as a rapidly progressive cerebellar ataxia, associated with cognitive decline. Late-onset cases are rare., Objective: To compare a novel GSS phenotype with six other cases and present pathological findings from a single case., Methods: Case series of seven GSS patients, one proceeding to autopsy., Results: Case 1 developed slowly progressive gait difficulties at age 71, mimicking a spinocerebellar ataxia, with a family history of balance problems in old age. Genome sequencing revealed a heterozygous c.392G > A (p.G131E) pathogenic variant and a c.395A > G resulting in p.129 M/V polymorphism in the PRNP gene. Probability analyses considering family history, phenotype, and a similar previously reported point mutation (p.G131V) suggest p.G131E as a new pathogenic variant. Clinical features and imaging of this case are compared with those six additional cases harboring p.P102L mutations. Autopsy findings of a case are described and were consistent with the prion pathology of GSS., Conclusions: We describe a patient with GSS with a novel p.G131E mutation in the PRNP gene, presenting with a late-onset, slowly progressive phenotype, mimicking a spinocerebellar ataxia, and six additional cases with the typical P102L mutation., (© 2024 International Parkinson and Movement Disorder Society.)

The interface between pediatric palliative care (PPC) and inborn metabolic diseases (IMD) remains incipient, though these conditions fill the state of art of complex chronic diseases, eligible to this health approach. We analyzed the medical records of PPC clinic during the years 2001 to 2021 and the IMD outpatients. We established a parallel with the world scientific literature concerning the epidemiology of PPC and IMD. Among outpatients, 14% were diagnosed with IMD, which were referred to the PPC service earlier compared to Non-IMD cases. The Group 3 (complex molecules) was the most frequent (64.7%), following by Group 1 representing by small molecules (21.6%), the latter having a lower median age at diagnosis when compared to the former (0.7 vs. 5.2 years, p  = 0.001). The sphingolipidoses were the pathologies most frequent in our cohort, in line with what was observed in the literature. There were no differences between IMD groups in terms of diagnosis and PPC referral age, however in Non-IMD conditions, the age of diagnosis were earlier than IMD. Nevertheless, IMD group showed lower age of referral to PPC. The IMD comprises large fraction of outpatients in the PPC setting, thus further studies are needed in this field., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Authors. JIMD Reports published by John Wiley & Sons Ltd on behalf of SSIEM.)

Background and Purpose: Krabbe disease (KD), or globoid cell leukodystrophy (Online Mendelian Inheritance in Man #245200), is an autosomal recessive lysosomal storage disease caused by mutations in GALC leading to galactocerebrosidase deficiency. Age at onset can vary from early infancy (3-6 months of age) to adulthood, which has rarely been reported. Little is known about the natural history and early manifestations of adult onset KD (AOKD)., Methods: Here, we report a patient with an incidental diagnosis of AOKD and discuss management options in this scenario., Results: A 32-year-old woman came to medical attention because of headache and had brain magnetic resonance imaging findings compatible with AOKD, two pathogenic variants in GALC, and reduced activity of galactocerebrosidase. The jury is still out about the best management of such cases, and clinicians should be aware of this diagnosis, as AOKD is a potentially treatable condition., Conclusions: AOKD is a rare and potentially treatable condition. More studies on natural history of AOKD are urgently needed to guide the best management of this disease., (© 2022 European Academy of Neurology.)

Background: Biallelic loss-of-function NDUFA12 variants have hitherto been linked to mitochondrial complex I deficiency presenting with heterogeneous clinical and radiological features in nine cases only., Objectives: To fully characterize, both phenotypically and genotypically, NDUFA12 -related mitochondrial disease., Methods: We collected data from cases identified by screening genetic databases of several laboratories worldwide and systematically reviewed the literature., Results: Nine unreported NDUFA12 cases from six pedigrees were identified, with presentation ranging from movement disorder phenotypes (dystonia and/or spasticity) to isolated optic atrophy. MRI showed basal ganglia abnormalities ( n  = 6), optic atrophy ( n  = 2), or was unremarkable ( n  = 1). All carried homozygous truncating NDUFA12 variants, three of which are novel., Conclusions: Our case series expands phenotype-genotype correlations in NDUFA12 -associated mitochondrial disease, providing evidence of intra- and inter-familial clinical heterogeneity for the same variant. It confirms NDUFA12 variants should be included in the diagnostic workup of Leigh/Leigh-like syndromes - particularly with dystonia - as well as isolated optic atrophy., Competing Interests: Biological samples from pedigree C were collected as part of the SYNaPS Study Group collaboration funded by The Wellcome Trust and strategic award (Synaptopathies) funding (WT093205 MA and WT104033AIA) and research was conducted as part of the Queen Square Genomics group at University College London, supported by the National Institute for Health Research University College London Hospitals Biomedical Research Centre. Biological samples from pedigree D were collected as part of the project RAC# 2121053. Francesca Magrinelli is supported by the Edmond J. Safra Foundation and by the research grant “Fondo Gianesini” in collaboration with UniCredit Foundation and University of Verona, Italy. Robert W. Taylor is supported by the Wellcome Centre for Mitochondrial Research (203,105/Z/16/Z), the MRC International Centre for Genomic Medicine in Neuromuscular Disease (MR/S005021/1), Mitochondrial Disease Patient Cohort (UK) (G0800674), the UK NIHR Biomedical Research Centre for Aging and Age‐related disease award to the Newcastle upon Tyne Foundation Hospitals NHS Trust, The Lily Foundation, the Pathology Society and the UK NHS Highly Specialized Service for Rare Mitochondrial Disorders of Adults and Children. Kailash P. Bhatia has received grant support from Wellcome/MRC, NIHR, Parkinson's UK and EU Horizon 2020. Tobias B. Haack was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—418081722, 433158657. Kate Sargeant thanks the UK NHS Specialist Commissioners, which funds the “Rare Mitochondrial Disease Service for Adults and Children” in Oxford for their support. The views expressed are those of the author(s) and not necessarily those of the NHS or the UK Department of Health and Social Care. Rita Horvath is a Wellcome Trust Investigator (109,915/Z/15/Z), who receives support from the Medical Research Council (UK) (MR/N025431/1 and MR/V009346/1), the European Research Council (309548), the Newton Fund (UK/Turkey, MR/N027302/1), the Addenbrookes Charitable Trust (G100142), the Evelyn Trust, the Stoneygate Trust, the Lily Foundation and an MRC strategic award to establish an International Centre for Genomic Medicine in Neuromuscular Diseases (ICGNMD) MR/S005021/1. This research was supported by the NIHR Cambridge Biomedical Research Centre (BRC‐1215‐20,014). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. Henry Houlden is funded by The MRC (MR/S01165X/1, MR/S005021/1, G0601943), The National Institute for Health Research University College London Hospitals Biomedical Research Centre, Rosetree Trust, Ataxia UK, MSA Trust, Brain Research UK, Sparks GOSH Charity, Muscular Dystrophy UK (MDUK), Muscular Dystrophy Association (MDA USA). The authors declare that there are no conflicts of interest relevant to this work., (© 2021 The Authors. Movement Disorders Clinical Practice published by Wiley Periodicals LLC. on behalf of International Parkinson and Movement Disorder Society.)

ATP6V1B2 encodes a subunit of the lysosomal transmembrane proton pump necessary for adequate functioning of several acid hydrolases. De novo monoallelic variants of this gene have been associated with two distinct phenotypes: Zimmermann-Laband syndrome 2 (ZLS2), an intellectual deficiency/multiple malformation syndrome, and dominant deafness onychodystrophy (DDOD), a multiple malformation syndrome without cognitive involvement. Epilepsy is not observed in DDOD, is variably present in ZLS2, but is a common feature in Zimmermann-Laband syndrome 1 (ZLS1) (caused by monoallelic pathogenic variants in KCNH1) and Zimmermann-Laband syndrome-like (ZLSL) (associated with KCNK4 variants). Herein, we report a case of an infant with severe epileptic encephalopathy with microcephaly and profound developmental delay, associated with a novel de novo loss-of-function variant in ATP6V1B2, diagnosed by whole-exome sequencing. This finding expands the spectrum of ATP6V1B2-associated disorders and adds ATP6V1B2 as a new member for the growing list of early-onset epileptic encephalopathy genes. [Published with video sequence].

Background and Purposes: Anti-aquaporin 4 antibodies are specific markers for Devic's disease. This study aimed to test if this high specificity holds in the context of a large spectrum of systemic autoimmune and non-autoimmune diseases., Methods: Anti-aquaporin-4 antibodies (NMO-IgG) were determined by indirect immunofluorescence (IIF) on mouse cerebellum in 673 samples, as follows: group I (clinically defined Devic's disease, n=47); group II [inflammatory/demyelinating central nervous system (CNS) diseases, n=41]; group III (systemic and organ-specific autoimmune diseases, n=250); group IV (chronic or acute viral diseases, n=35); and group V (randomly selected samples from a general clinical laboratory, n=300)., Results: MNO-IgG was present in 40/47 patients with classic Devic's disease (85.1% sensitivity) and in 13/22 (59.1%) patients with disorders related to Devic's disease. The latter 13 positive samples had diagnosis of longitudinally extensive transverse myelitis (n=10) and isolated idiopathic optic neuritis (n=3). One patient with multiple sclerosis and none of the remaining 602 samples with autoimmune and miscellaneous diseases presented NMO-IgG (99.8% specificity). The autoimmune disease subset included five systemic lupus erythematosus individuals with isolated or combined optic neuritis and myelitis and four primary Sjögren's syndrome (SS) patients with cranial/peripheral neuropathy., Conclusions: The available data clearly point to the high specificity of anti-aquaporin-4 antibodies for Devic's disease and related syndromes also in the context of miscellaneous non-neurologic autoimmune and non-autoimmune disorders., (© 2011 The Author(s). European Journal of Neurology © 2011 EFNS.)

Metachromatic leukodystrophy (MLD) is a lysosomal disorder caused by arylsulfatase A (ARSA) deficiency. It is classified into three forms according to the age of onset of symptoms (late infantile, juvenile, and adult). We carried out a cross-sectional and retrospective study, which aimed to determine the epidemiological, clinical, and biochemical profile of MLD patients from a national reference center for Inborn Errors of Metabolism in Brazil. Twenty-nine patients (male, 17) agreed to participate in the study (late infantile form: 22; juvenile form: 4; adult form: 1; asymptomatic: 2). Mean ages at onset of symptoms and at biochemical diagnosis were, respectively, 19 and 39 months for late infantile form and 84.7 and 161.2 months for juvenile form. The most frequently reported first clinical symptom/sign of the disease was gait disturbance and other motor abnormalities (72.7%) for late infantile form and behavioral and cognitive alterations (50%) for juvenile form. Leukocyte ARSA activity level did not present significant correlation with the age of onset of symptoms (r = -0.09, p = 0.67). Occipital white matter and basal nuclei abnormalities were not found in patients with the late infantile MLD. Our results suggest that there is a considerable delay between the age of onset of signs and symptoms and the diagnosis of MLD in Brazil. Correlation between ARSA activity and MLD clinical form was not found. Further studies on the epidemiology and natural history of this disease with larger samples are needed, especially now when specific treatments should be available in the near future.

Mitochondriopathies are a heterogeneous group of diseases with variable phenotypic presentation, which can range from subclinical to lethal forms. They are related either to DNA mutations or nuclear-encoded mitochondrial genes that affect the integrity and function of these organelles, compromising adenosine triphosphate (ATP) synthesis. Magnetic resonance (MR) is the most important imaging technique to detect structural and metabolic brain abnormalities in mitochondriopathies, although in some cases these studies may present normal results, or the identified brain abnormalities may be nonspecific. Magnetic resonance spectroscopy (MRS) enables the detection of high cerebral lactate levels, even when the brain has normal appearance by conventional MR scans. MRS is a useful tool for the diagnosis of mitochondriopathies, but must be correlated with clinical, neurophysiological, biochemical, histological, and molecular data to corroborate the diagnosis. Our aim is to clarify the most relevant issues related to the use of MRS in order to optimize its technical parameters, improving its use in the diagnosis of mitochondriopathies, which is often a challenge.

Multivariate analysis in case-base designs depends on approximate methods. In the present study, new pseudo-likelihood methods are developed for this design. With these methods, the case-cohort risk ratio and rate ratio as well as their standard errors are easily estimated using logistic regression and Poisson regression, respectively. This is illustrated by the association between hypertension and cardiovascular mortality in a cohort, estimated by case-cohort analysis, using samples of several sizes. The estimates are compared with those obtaining in full-cohort and nested case-control designs. The results indicate that these methods, which require nothing but widely available computer software, are valid. The case-cohort design, therefore, is a good, sometimes even advantageous alternative to the nested case-control design, in studying a disease that is not very rare. Application of the risk ratio method to the full cohort, using a 'sample' of 100 per cent follows logically; whenever the true risk ratio is desired instead of the odds ratio, a multivariate model for its estimation is therefore available.