Rare Progressive Neurodegenerative Disorder Research Articles

Cardiac Arrest as the Initial Presentation of Leigh Syndrome Associated with Novel NDUFS1 Mutation

Leigh syndrome is a rare progressive neurodegenerative mitochondrial disorder. Over 75 pathogenic mutations have been identified in both the mitochondrial and nuclear genomes. Leigh syndrome can be diagnosed based on clinical manifestations, physical and biochemical examinations, and brain magnetic resonance imaging results. Patients with Leigh syndrome classically present in early childhood with developmental regression, ataxia, and hypotonia with subsequent respiratory and brainstem dysfunction. However, the clinical course of Leigh syndrome is heterogeneous with significant differences in age of onset, symptom severity and prognosis. Here, we report a case of Leigh syndrome with cardiac arrest as initial presentation, and identified the novel mutation of <i>NDUFS1</i> gene.

An Unusual Presentation of Neuronal Ceroid Lipofuscinosis With CLN6 Mutation

Background: Neuronal ceroid lipofuscinoses (NCL) is a rare progressive neurodegenerative disorder caused by more than 530 mutations of at least 13 different genes (CLN 1-14). NCL is a part of the lysosomal disease characterized by the presence of neuronal and extraneural autofluorescent lipopigment accumulations that leads to motor and mental deterioration, developmental regression, seizure, vision loss, and premature death. NCL is classified into four main groups based on the different clinical manifestations and age of presentation. In this study, we aimed to report an unusual presentation of NCL with CLN6 mutation without retina involvement. Case Presentation: We reported a 10-year-old boy with mixed types of seizures, developmental delay, cognitive problems, unsteady gait, and speech disorders. Although after a thorough assessment, CLN6 mutation was diagnosed, he had all symptoms of this mutation, except the visual impairment. Conclusion: According to recent NCL case reports from Asia, full familiarity with its presentation by pediatricians and neurologists is obligatory. Children with developmental regression or refractory seizures, who also have visual or other neurological symptoms such as ataxia and other cerebellar symptoms, even at older ages, should be evaluated for NCL. Attention to ophthalmological examinations and neurological signs and confirming the diagnosis by biopsy or genetic analysis is desirable to prevent missed diagnosis.

Characteristics of spinal and bulbar muscular atrophy in South Korea: a cross-sectional study of 157 patients.

Spinal and bulbar muscular atrophy, namely Kennedy disease, is a rare progressive neurodegenerative disorder caused by the expansion of a CAG repeat in the first exon of the androgen receptor gene on the X chromosome. We assessed the clinical history, laboratory findings, functional scales and electrophysiological data, as well as the levels of luteinizing hormone, follicle-stimulating hormone and testosterone, in 157 Korean patients with genetically confirmed spinal and bulbar muscular atrophy (mean age at data collection = 56.9 years; range = 33-83 years). Hand tremor was the first symptom noticed by patients at a median age of 35 years, followed by gynaecomastia, orofacial fasciculation, cramps and fatigability in ascending order. Clinical symptoms such as paraesthesia and dysphagia appeared during the later stages of the disease. Cane use during ambulation began at a median age of 62 years. There were statistically significant differences between patients and controls in the results of sensory nerve studies, motor conduction velocity, and distal latencies. Furthermore, among the hormone markers analysed, the level of luteinizing hormone exhibited a negative correlation with the spinal and bulbar muscular atrophy functional rating scale, Korean version. However, among the patients with a disease duration of ≤5 years, the levels of luteinizing hormone showed a significant correlation with assessments using the amyotrophic lateral sclerosis functional rating scale-revised, spinal and bulbar muscular atrophy functional rating scale, Korean version and the 6-minute walk test. In conclusion, our findings provide clinical information from a substantial number of patients with spinal and bulbar muscular atrophy in Korea that accorded with that of patients with this disease worldwide but with updated clinical features.

Sporadic Creutzfeldt–Jacob Disease: A case report

Purpose: Creutzfeldt–Jacob Disease (CJD) is a rare progressive neurodegenerative disorder and the most common form of prion disease. CJD is categorized into four subtypes: sporadic (sCJD), familial, iatrogenic, and variant. The clinical presentation of sCJD is characterized by progressive dementia, myoclonus, visual disturbances, cerebellar ataxia, and pyramidal and/ or extrapyramidal signs. Diagnosis is based on clinical presentation, and the results of an electroencephalogram, cerebrospinal fluid analysis, and cranial magnetic resonance imaging.
 Case Report: The case of an 81-yearold woman with progressive dementia and typical electroencephalogram and magnetic resonance imaging findings for sporadic is presented.
 Conclusion: No single diagnostic test for sCJD is available. In suspected sCJD, the first priority is to exclude treatable forms of dementia, such as encephalitis or chronic meningitis.

Clinicopathological features of neuronal intranuclear inclusion disease diagnosed by skin biopsy.

Neuronal intranuclear inclusion disease (NIID) is a rare progressive neurodegenerative disorder, with complex and diverse of clinical manifestations characterized by eosinophilic hyaline inclusions in neurons and somatic cells. Due to the improvement in diagnostic methods, NIID is being increasingly diagnosed. Herein, we reported three NIID cases, which were diagnosed by skin biopsy and FMR1 gene, after DWI showed the characteristic corticomedullary junction hyperintensity. Then we reviewed all the published cases of NIID in PubMed, which were diagnosed by the same method. We discussed 15 NIID cases, including three cases diagnosed by us. The average age was 63.4 ± 14.0years. The average time from onset of symptom to diagnosis was 5.4 ± 7.9years. Nine cases had dementia or cognitive impairment. Three cases presented with encephalitis. Three cases showed bladder dysfunction and two cases only presented with dizziness and headache. Two cases showed acute neurological deficit mimicking stroke. All cases were diagnosed by skin biopsy, after DWI showed abnormal corticomedullary junction hyperintensity. Ten cases showed inclusions in sweat gland cells, and seven cases in adipocytes, sweat gland cells, and fibroblasts. EMG was performed in five cases, four of whom had abnormal results, showing simultaneous involvement of motor and sensory nerves. The results indicated that inclusions were more easily detected in sweat gland cells in skin biopsy. The early stage of NIID could only characterized by autonomic nerve function involvement. Combined autonomic nerve dysfunction might be another relatively common manifestation in NIID.

Generation of an iPSC line (AKOSi004-A) from fibroblasts of a female adult NPC1 patient, carrying the compound heterozygous mutation p.Val1023Serfs*15/p.Gly992Arg and of an iPSC line (AKOSi005-A) from a female adult control individual.

Niemann-Pick disease Type C (NPC) is a rare progressive neurodegenerative disorder with an incidence of 1:120,000 caused by mutations in the NPC1 or NPC2 gene leading to a massive cholesterol accumulation. Here, we describe the generation of induced pluripotent stem cells (iPSCs) of an affected female adult individual carrying the NPC1 mutation p.Val1023Serfs*15/p.Gly992Arg and an iPSC line from an unrelated healthy female adult control individual. Human iPSCs were derived from fibroblasts using retroviruses carrying the four reprogramming factors OCT4, SOX2, KLF4 and C-MYC. These lines provide a valuable resource for studying the pathophysiology of NPC and for pharmacological intervention.

Generation of the Niemann-Pick type C2 patient-derived iPSC line AKOSi001-A.

Niemann-Pick disease Type C (NPC) is a rare progressive neurodegenerative disorder with an incidence of 1:120,000 caused by mutations in the NPC1 or NPC2 gene. Only 5% of NPC patients suffer from mutations of the NPC2 gene. Here we demonstrate the generation of a Niemann-Pick disease Type C2 (NPC2) patient-derived induced pluripotent stem cell line. This cell line is capable to differentiate into derivatives of the neuronal lineage, providing a valuable tool to study pathogenic mechanisms of NPC2.

Customized Dietary Intervention Avoids Unintentional Weight Loss and Modulates Circulating miRNAs Footprint in Huntington's Disease

Huntington's disease (HD) is a rare progressive neurodegenerative disorder of genetic origin, with no definitive treatment. Unintentional weight loss (UWL) is a clinical feature of symptomatic HD subjects. To prevent UWL, a customized HD diet is designed and its impact on plasma miRNA HD footprint and neurological parameters is examined. Eleven participants are included, BMI≤18 kgm-2 or UWL of 5% in 6 months or 10% in a year. Diet design is based on nutritional surveys and interviews of participants and caregivers and on published literature review. Twelve-month dietary intervention, with follow-up every 3 months, induces high diet adherence, which manages to curb UWL in all participants (73% gained weight). Noticeable increases in fat mass and leptin levels are obtained. The results also show significant decrease in the expression of 19 miRNAs, which are previously reported to be upregulated in HD-patients versus healthy controls: revealing hsa-miR-338-3p, hsa-miR-128-3p, hsa-miR-23a-3p, and hsa-miR-24-3p as potential HD-biomarkers. The diminished expression of hsa-miR-100-5p reflects the general maintenance of the functional status. Cognitive status is improved in six of 11 participants, while only three present better motor-score values. A customized HD-diet prevents UWL and modified miRNAs HD-footprint. The normalization of miRNA values suggests its potentially use as HD-biomarkers.

Cytochrome C oxydase deficiency: SURF1 gene investigation in patients with Leigh syndrome

Leigh syndrome (LS) is a rare progressive neurodegenerative disorder occurring in infancy. The most common clinical signs reported in LS are growth retardation, optic atrophy, ataxia, psychomotor retardation, dystonia, hypotonia, seizures and respiratory disorders. The paper reported a manifestation of 3 Tunisian patients presented with LS syndrome. The aim of this study is the MT[HYPHEN]ATP6 and SURF1 gene screening in Tunisian patients affected with classical Leigh syndrome and the computational investigation of the effect of detected mutations on its structure and functions by clinical and bioinformatics analyses. After clinical investigations, three Tunisian patients were tested for mutations in both MT-ATP6 and SURF1 genes by direct sequencing followed by in silico analyses to predict the effects of sequence variation. The result of mutational analysis revealed the absence of mitochondrial mutations in MT-ATP6 gene and the presence of a known homozygous splice site mutation c.516-517delAG in sibling patients added to the presence of a novel double het mutations in LS patient (c.752-18 A > C/c. c.751 + 16G > A). In silico analyses of theses intronic variations showed that it could alters splicing processes as well as SURF1 protein translation. Leigh syndrome (LS) is a rare progressive neurodegenerative disorder occurring in infancy. The most common clinical signs reported in LS are growth retardation, optic atrophy, ataxia, psychomotor retardation, dystonia, hypotonia, seizures and respiratory disorders. The paper reported a manifestation of 3 Tunisian patients presented with LS syndrome. The aim of this study is MT-ATP6 and SURF1 genes screening in Tunisian patients affected with classical Leigh syndrome and the computational investigation of the effect of detected mutations on its structure and functions. After clinical investigations, three Tunisian patients were tested for mutations in both MT-ATP6 and SURF1 genes by direct sequencing followed by in silico analysis to predict the effects of sequence variation. The result of mutational analysis revealed the absence of mitochondrial mutations in MT-ATP6 gene and the presence of a known homozygous splice site mutation c.516-517delAG in sibling patients added to the presence of a novel double het mutations in LS patient (c.752-18 A>C/ c.751+16G>A). In silico analysis of theses intronic vaiations showed that it could alters splicing processes as well as SURF1 protein translation.

CRISPR-Cas9-Mediated Correction of the 1.02 kb Common Deletion in CLN3 in Induced Pluripotent Stem Cells from Patients with Batten Disease.

Juvenile neuronal ceroid lipofuscinosis (Batten disease) is a rare progressive neurodegenerative disorder caused by mutations in CLN3. Patients present with early-onset retinal degeneration, followed by epilepsy, progressive motor deficits, cognitive decline, and premature death. Approximately 85% of individuals with Batten disease harbor at least one allele containing a 1.02 kb genomic deletion spanning exons 7 and 8. This study demonstrates CRISPR-Cas9-based homology-dependent repair of this mutation in induced pluripotent stem cells generated from two independent patients: one homozygous and one compound heterozygous for the 1.02 kb deletion. Our strategy included delivery of a construct that carried >3 kb of DNA: wild-type CLN3 sequence and a LoxP-flanked, puromycin resistance cassette for positive selection. This strategy resulted in correction at the genomic DNA and mRNA levels in the two independent patient lines. These CRISPR-corrected isogenic cell lines will be a valuable tool for disease modeling and autologous retinal cell replacement.

Activation of PKC triggers rescue of NPC1 patient specific iPSC derived glial cells from gliosis

BackgroundNiemann-Pick disease Type C1 (NPC1) is a rare progressive neurodegenerative disorder caused by mutations in the NPC1 gene. The pathological mechanisms, underlying NPC1 are not yet completely understood. Especially the contribution of glial cells and gliosis to the progression of NPC1, are controversially discussed. As an analysis of affected cells is unfeasible in NPC1-patients, we recently developed an in vitro model system, based on cells derived from NPC1-patient specific iPSCs. Here, we asked if this model system recapitulates gliosis, observed in non-human model systems and NPC1 patient post mortem biopsies. We determined the amount of reactive astrocytes and the regulation of the intermediate filaments GFAP and vimentin, all indicating gliosis. Furthermore, we were interested in the assembly and phosphorylation of these intermediate filaments and finally the impact of the activation of protein kinase C (PKC), which is described to ameliorate the pathogenic phenotype of NPC1-deficient fibroblasts, including hypo-phosphorylation of vimentin and cholesterol accumulation.MethodsWe analysed glial cells derived from NPC1 patient specific induced pluripotent stem cells, carrying different NPC1 mutations. The amount of reactive astrocytes was determined by means of immuncytochemical stainings and FACS-analysis. Semi-quantitative western blot was used to determine the amount of phosphorylated GFAP and vimentin. Cholesterol accumulation was analysed by Filipin staining and quantified by Amplex Red Assay. U18666A was used to induce NPC1 phenotype in unaffected cells of the control cell line. Phorbol 12-myristate 13-acetate (PMA) was used to activate PKC.ResultsImmunocytochemical detection of GFAP, vimentin and Ki67 revealed that NPC1 mutant glial cells undergo gliosis. We found hypo-phosphorylation of the intermediate filaments GFAP and vimentin and alterations in the assembly of these intermediate filaments in NPC1 mutant cells. The application of U18666A induced not only NPC1 phenotypical accumulation of cholesterol, but characteristics of gliosis in glial cells derived from unaffected control cells. The application of phorbol 12-myristate 13-acetate, an activator of protein kinase C resulted in a significantly reduced number of reactive astrocytes and further characteristics of gliosis in NPC1-deficient cells. Furthermore, it triggered a restoration of cholesterol amounts to level of control cells.ConclusionOur data demonstrate that glial cells derived from NPC1-patient specific iPSCs undergo gliosis. The application of U18666A induced comparable characteristics in un-affected control cells, suggesting that gliosis is triggered by hampered function of NPC1 protein. The activation of protein kinase C induced an amelioration of gliosis, as well as a reduction of cholesterol amount. These results provide further support for the line of evidence that gliosis might not be only a secondary reaction to the loss of neurons, but might be a direct consequence of a reduced PKC activity due to the phenotypical cholesterol accumulation observed in NPC1. In addition, our data support the involvement of PKCs in NPC1 disease pathogenesis and suggest that PKCs may be targeted in future efforts to develop therapeutics for NPC1 disease.

Validity and reliability of a pilot scale for assessment of multiple system atrophy symptoms

BackgroundMultiple system atrophy (MSA) is a rare progressive neurodegenerative disorder for which brief yet sensitive scale is required in order for use in clinical trials and general screening. We previously compared several scales for the assessment of MSA symptoms and devised an eight-item pilot scale with large standardized response mean [handwriting, finger taps, transfers, standing with feet together, turning trunk, turning 360°, gait, body sway]. The aim of the present study is to investigate the validity and reliability of a simple pilot scale for assessment of multiple system atrophy symptoms.MethodsThirty-two patients with MSA (15 male/17 female; 20 cerebellar subtype [MSA-C]/12 parkinsonian subtype [MSA-P]) were prospectively registered between January 1, 2014 and February 28, 2015. Patients were evaluated by two independent raters using the Unified MSA Rating Scale (UMSARS), Scale for Assessment and Rating of Ataxia (SARA), and the pilot scale. Correlations between UMSARS, SARA, pilot scale scores, intraclass correlation coefficients (ICCs), and Cronbach’s alpha coefficients were calculated.ResultsPilot scale scores significantly correlated with scores for UMSARS Parts I, II, and IV as well as with SARA scores. Intra-rater and inter-rater ICCs and Cronbach’s alpha coefficients remained high (> 0.94) for all measures.ConclusionThe results of the present study indicate the validity and reliability of the eight-item pilot scale, particularly for the assessment of symptoms in patients with early state multiple system atrophy.

Decreased calcium flux in Niemann-Pick type C1 patient-specific iPSC-derived neurons due to higher amount of calcium-impermeable AMPA receptors.

Niemann-Pick disease type C1 (NPC1) is a rare progressive neurodegenerative disorder caused by mutations in the NPC1 gene, resulting mainly in the accumulation of cholesterol and the ganglioside GM2. Recently, we described accumulations of these lipids in neuronal differentiated cells derived from NPC1 patient-specific induced pluripotent stem cells (iPSCs). As these lipids are essential for proper cell membrane composition, we were interested in the expression and function of voltage-gated ion channels and excitatory AMPA receptors (AMPARs) in neurons derived from three patient-specific iPSC lines. By means of patch clamp recordings and microfluorimetric measurements of calcium (Ca2+), we examined the expression of voltage-gated ion channels and AMPARs. Cells of the three used cell lines carrying the c.1836A>C/c.1628delC, the c.1180T>C or the c.3182T>C mutation demonstrated a significantly reduced AMPA-induced Ca2+-influx, suggesting an altered expression profile of these receptors. RT-qPCR revealed a significant upregulation of mRNA for the AMPA receptor subunits GluA1 and GluA2 and western blot analysis showed increased protein level of GluA2. Thus, we conclude that the observed reduced Ca2+-influx is based on an increase of GluA2 containing Ca2+-impermeable AMPARs. An attenuated function of GluRs in neurons potentially contributes to the progressive neurodegeneration observed in NPC1 and might represent an objective in regard of the development of new therapeutic approaches in NPC1.

Diversity of glycosphingolipid GM2 and cholesterol accumulation in NPC1 patient-specific iPSC-derived neurons

Niemann-Pick disease Type C1 (NPC1) is a rare progressive neurodegenerative disorder caused by mutations in the NPC1 gene. On the cellular level NPC1 mutations lead to an accumulation of cholesterol and gangliosides. As a thorough analysis of the severely affected neuronal cells is unfeasible in NPC1 patients, we recently described the cellular phenotype of neuronal cells derived from NPC1 patient iPSCs carrying the compound heterozygous mutation c.1836A>C/c.1628delC. Here we expanded the analysis to cell lines carrying the prevalent mutation c.3182T>C and the novel mutation c.1180T>C, as well as to the determination of GM2 and GM3 gangliosides in NPC1 patient-specific iPSC-derived neurons and glia cells. Immunocytochemical detection of GM2 revealed punctated staining pattern predominantly localized in neurons. Detection of cholesterol by filipin staining showed a comparable staining pattern, colocalized with GM2, indicating a deposit of GM2 and cholesterol in the same cellular compartments. Accumulations were not only restricted to cell bodies, but were also found in the neuronal extensions. A quantification of the GM2 amount by HPLC-MS/MS confirmed significantly higher amounts in neurons carrying a mutation. Additionally, these cells displayed a lowered activity of the catabolic enzyme Hex A, but not B4GALNT1. Molecular docking simulations indicated binding of cholesterol to Hex A, suggesting cholesterol influences the GM2 degradation pathway and, subsequently, leading to the accumulation of GM2. Taken together, this is the first study showing an accumulation of GM2 in neuronal derivatives of patient-specific iPSCs and thus proving further disease-specific hallmarks in this human in vitro model of NPC1.

MAPT haplotype diversity in multiple system atrophy

IntroductionMultiple system atrophy (MSA) is a rare progressive neurodegenerative disorder. MSA was originally considered exclusively sporadic but reports of association with genes such as SNCA, COQ2 and LRRK2 have demonstrated that there is a genetic contribution to the disease. MAPT has been associated with several neurodegenerative diseases and we previously reported a protective association of the MAPT H2 haplotype with MSA in 61 pathologically confirmed cases. MethodsIn the present study, we assessed the full MAPT haplotype diversity in MSA patients using six MAPT tagging SNPs. We genotyped a total of 127 pathologically confirmed MSA cases, 86 patients with clinically diagnosed MSA and 1312 controls. ResultsWe identified four significant association signals in our pathologically confirmed cases, two from the protective haplotypes H2 (MSA:16.2%, Controls:22.7%, p = 0.024) and H1E (MSA:3.0%, Controls:9.0%, p = 0.014), and two from the rare risk haplotypes H1x (MSA:3.7%, Controls:1.3%, p = 0.030) and H1J (MSA:3.0%, Controls:0.9%, p = 0.021). We evaluated the association of MSA subtypes with the common protective H2 haplotype and found a significant difference with controls for MSA patients with some degree of MSA-C (MSA-C or MSA-mixed), for whom H2 occurred in only 8.6% of patients in our pathologically confirmed series (P < 0.0001). ConclusionsOur findings provide further evidence that MAPT variation is associated with risk of MSA. Interestingly, our results suggest a greater effect size in the MSA-C compared to MSA-P for H2. Additional genetic studies in larger pathologically confirmed MSA series and meta-analytic studies will be needed to fully assess the role of MAPT and other genes in MSA.

LC-MS/MS based assay and reference intervals in children and adolescents for oxysterols elevated in Niemann–Pick diseases

BackgroundNiemann–Pick type C (NP-C) is a rare progressive neurodegenerative lipid storage disorder with heterogeneous clinical presentation and challenging diagnostic procedures. Recently oxysterols have been reported to be specific biomarkers for NP-C but knowledge on the intra-individual variation and on reference intervals in children and adolescents are lacking. MethodsWe established a LC-MS/MS assay to measure Cholestane-3β, 5α, 6β-triol (C-triol) and 7-Ketocholesterol (7-KC) following Steglich esterification. To assess reference intervals and intra-individual variation we determined oxysterols in 148 children and adolescents from 0 to 18 years and repeat measurements in 19 of them. ResultsThe reported method is linear (r>0.99), sensitive (detection limit of 0.03 ng/mL [0.07 nM] for C-triol, and 0.54 ng/mL [1.35 nM] for 7-KC) and precise, with an intra-day imprecision of 4.8% and 4.1%, and an inter-day imprecision of 7.0% and 11.0% for C-triol (28 ng/ml, 67 nM) and 7-KC (32 ng/ml, 80 nM), respectively. Recoveries for 7-KC and C-triol range between 93% and 107%.The upper reference limit obtained for C-triol is 40.4 ng/mL (95% CI: 26.4–61.7 ng/mL, 96.0 nM, 95% CI: 62.8–146.7 nM) and 75.0 ng/mL for 7-KC (95% CI: 55.5–102.5 ng/mL, 187.2 nM, 95% CI: 138.53–255.8 nM), with no age or gender dependency. Both oxysterols have a broad intra-individual variation of 46%±23% for C-triol and 52%±29% for 7-KC. Nevertheless, all Niemann–Pick patients showed increased C-triol levels including Niemann–Pick type A and B patients. ConclusionsThe LC-MS/MS assay is a robust assay to quantify C-triol and 7-KC in plasma with well documented reference intervals in children and adolescents to screen for NP-C in the pediatric population. In addition our results suggest that especially the C-triol is a biomarker for all three Niemann–Pick diseases.

Niemann-Pick Disease Type C Presenting as a Developmental Coordination Disorder with Bullying by Peers in a School-Age Child.

Niemann-Pick disease type C (NPC) is a rare progressive neurodegenerative disorder, often with onset after normal early childhood development. Juvenile onset NPC patients slowly develop cerebellar symptoms and cognitive impairment and often experience difficulties at school. However, these problems may be overlooked due to the unpublicized nature of NPC, given that it is a rare metabolic disorder. In this report, we present an 11-year-old male NPC patient, who suffered from clumsiness and difficulties in attention and academic and social skills. His symptoms were initially considered to be due to developmental coordination disorder (DCD) coexisting with bullying by peers. DCD is a type of neurodevelopmental disorder defined according to DSM-IV and is characterized by clumsiness that interferes with academic achievement and social integration not due to other general medical conditions. However, a detailed investigation of the patient suggested that the problems could be attributed to the onset of NPC. Clinicians should keep neurodegenerative disorders as differential diagnosis of children with multiple school problems.

THE MULTIDISCIPLINARY ADULT ATAXIA TELANGIECTASIA SERVICE

Background Ataxia Telangiectasia (AT) is a rare progressive neurodegenerative disorder with no proven interventions to prevent or delay disease progression. Papworth Hospital NHS Foundation Trust is nationally commissioned to provide an annual multidisciplinary team (MDT) review for adult patients with AT following on from their paediatric care. Methods We conducted a retrospective evaluation of patients seen between May and November 2013 specifically assessing the outcomes of MDT discussion for each patient and new recommendations made to local healthcare providers following a 36-hour admission for annual review. The MDT consisted of a neurologist, respiratory physician, immunologist, physiotherapist, occupational therapist (OT), social worker (SW) and speech and language therapist. Results Seventeen patients (3 new/14 follow-up) were assessed. A minimum of six out of seven MDT members attended meetings. A total of 65 new recommendations were made. All members of the team contributed with the most recommendations provided by OT and SW. Examples of recommendations include: optimisation of home ergonomics, initiation of anti-depressants and botox for dystonia. Conclusion In a rare degenerative neurological condition re-evaluation by a specialist MDT, whilst not affecting disease progression, leads to novel interventions to improve patient care.

GM1-gangliosidosis in American black bears: Clinical, pathological, biochemical and molecular genetic characterization

GM1-gangliosidosis is a rare progressive neurodegenerative disorder due to an autosomal recessively inherited deficiency of lysosomal β-galactosidase. We have identified seven American black bears (Ursus americanus) found in the Northeast United States suffering from GM1-gangliosidosis. This report describes the clinical features, brain MRI, and morphologic, biochemical and molecular genetic findings in the affected bears. Brain lipids were compared with those in the brain of a GM1-mouse. The bears presented at ages 10–14months in poor clinical condition, lethargic, tremulous and ataxic. They continued to decline and were humanely euthanized. The T2-weighted MR images of the brain of one bear disclosed white matter hyperintensity. Morphological studies of the brain from five of the bears revealed enlarged neurons with foamy cytoplasm containing granules. Axonal spheroids were present in white matter. Electron microscopic examination revealed lamellated membrane structures within neurons. Cytoplasmic vacuoles were found in the liver, kidneys and chondrocytes and foamy macrophages within the lungs. Acid β-galactosidase activity in cultured skin fibroblasts was only 1–2% of control values. In the brain, ganglioside-bound sialic acid was increased more than 2-fold with GM1-ganglioside predominating. GA1 content was also increased whereas cerebrosides and sulfatides were markedly decreased. The distribution of gangliosides was similar to that in the GM1-mouse brain, but the loss of myelin lipids was greater in the brain of the affected bear than in the brain of the GM1 mouse. Isolated full-length cDNA of the black bear GLB1 gene revealed 86% homology to its human counterpart in nucleotide sequence and 82% in amino acid sequence. GLB1 cDNA from liver tissue of an affected bear contained a homozygous recessive T1042 to C transition inducing a Tyr348 to His mutation (Y348H) within a highly conserved region of the GLB1 gene. The coincidence of several black bears with GM1-gangliosidosis in the same geographic area suggests increased frequency of a founder mutation in this animal population.

Incidence and carrier frequency of Sandhoff disease in Saskatchewan determined using a novel substrate with detection by tandem mass spectrometry and molecular genetic analysis

Sandhoff disease is a rare progressive neurodegenerative genetic disorder with a high incidence among certain isolated communities and ethnic groups around the world. Previous reports have shown a high occurrence of Sandhoff disease in northern Saskatchewan. Newborn screening cards from northern Saskatchewan were retrospectively screened in order to investigate the incidence and determine the carrier frequency of Sandhoff disease in these communities. PCR-based screening was conducted for the c.115delG (p.(Val39fs)) variant in the HEXB gene that was previously found in 4 Sandhoff disease patients from this area. The carrier frequency for this allele was estimated to be ~1:27. MS/MS-based screening of hexosaminidase activity along with genetic sequencing allowed for the identification of additional variants based on low total hexosaminidase activity and high % hexosaminidase A activity relative to c.115delG carriers. In total 4 pathogenic variants were discovered in the population (c.115delG, c.619A>G, c.1601G>T, and c.1652G>A) of which two are previously unreported (c.1601G>T and c.1652G>A). The combined carrier frequency of these alleles in the study area was estimated at ~1:15. Based on the number of cases of Sandhoff disease from this area we estimate the incidence to be ~1:390 corresponding to a child being born with the disease every 1–2years on average. The results from our study were then compared with variants in the HEXB gene from the genomes available from the 1000 Genomes project. A total of 19 HEXB variants were found in the 1092 genomes of which 5 are suspected of having a deleterious effect on hexosaminidase activity. The estimated carrier frequency of Sandhoff disease in Saskatchewan at 1:15 is more than 3 times higher than the carrier frequency in the global sample provided by the 1000 Genomes project at 1:57.