The c.-265G>A GLA gene promoter variant causes Fabry disease: The hidden culprit identified.

Here, we report the identification and functional characterization of a novel GLA variant, not detectable by routine molecular tests, in a family with FD suspicion.

Deficiency of Glucocerebrosidase Activity beyond Gaucher Disease: PSAP and LIMP-2 Dysfunctions.

Glucocerebrosidase (GCase) is a lysosomal enzyme that catalyzes the breakdown of glucosylceramide in the presence of its activator saposin C (SapC). SapC arises from the proteolytical cleavage of prosaposin (encoded by PSAP gene), which gives rise to four saposins. GCase is targeted to the lysosomes by LIMP-2, encoded by SCARB2 gene. GCase deficiency causes Gaucher Disease (GD), which is mainly due to biallelic pathogenetic variants in the GCase-encoding gene, GBA1. However, impairment of GCase activity can be rarely caused by SapC or LIMP-2 deficiencies. We report a new case of LIMP-2 deficiency and a new case of SapC deficiency (missing all four saposins, PSAP deficiency), and measured common biomarkers of GD and GCase activity. Glucosylsphingosine and chitotriosidase activity in plasma were increased in GCase deficiencies caused by PSAP and GBA1 mutations, whereas SCARB2-linked deficiency showed only Glucosylsphingosine elevation. GCase activity was reduced in fibroblasts and leukocytes: the decrease was sharper in GBA1- and SCARB2-mutant fibroblasts than PSAP-mutant ones; LIMP-2-deficient leukocytes displayed higher residual GCase activity than GBA1-mutant ones. Finally, we demonstrated that GCase mainly undergoes proteasomal degradation in LIMP-2-deficient fibroblasts and lysosomal degradation in PSAP-deficient fibroblasts. Thus, we analyzed the differential biochemical profile of GCase deficiencies due to the ultra-rare PSAP and SCARB2 biallelic pathogenic variants in comparison with the profile observed in GBA1-linked GCase deficiency.

Relief of nocturnal neuropathic pain with the use of cannabis in a patient with Fabry disease.

Neuropathic pain is one of the most invalidating symptoms in patients with Fabry disease (FD), affecting their quality of life, it is linked to small fiber neuropathy and it may not respond to available disease specific treatments. We report the case of a 32 years old man with classic FD and severe neuropathic pain who, after the failure of several standard pharmaceutical approaches, was treated with medical cannabis with relief of nocturnal pain and sleep improvement.

Understanding the phenotypic variability in Niemann-Pick disease type C (NPC): a need for precision medicine.

Niemann-Pick type C (NPC) disease is a lysosomal storage disease (LSD) characterized by the buildup of endo-lysosomal cholesterol and glycosphingolipids due to loss of function mutations in the NPC1 and NPC2 genes. NPC patients can present with a broad phenotypic spectrum, with differences at the age of onset, rate of progression, severity, organs involved, effects on the central nervous system, and even response to pharmacological treatments. This article reviews the phenotypic variation of NPC and discusses its possible causes, such as the remaining function of the defective protein, modifier genes, sex, environmental cues, and splicing factors, among others. We propose that these factors should be considered when designing or repurposing treatments for this disease. Despite its seeming complexity, this proposition is not far-fetched, considering the expanding interest in precision medicine and easier access to multi-omics technologies.

Exploring the Pathophysiologic Cascade Leading to Osteoclastogenic Activation in Gaucher Disease Monocytes Generated via CRISPR/Cas9 Technology.

Gaucher disease (GD) is caused by biallelic pathogenic variants in the acid ß-glucosidase gene (GBA1), leading to a deficiency in the ß-glucocerebrosidase (GCase) enzyme activity resulting in the intracellular accumulation of sphingolipids. Skeletal alterations are one of the most disabling features in GD patients. Although both defective bone formation and increased bone resorption due to osteoblast and osteoclast dysfunction contribute to GD bone pathology, the molecular bases are not fully understood, and bone disease is not completely resolved with currently available specific therapies. For this reason, using editing technology, our group has developed a reliable, isogenic, and easy-to-handle cellular model of GD monocytes (GBAKO-THP1) to facilitate GD pathophysiology studies and high-throughput drug screenings. In this work, we further characterized the model showing an increase in proinflammatory cytokines (Interleukin-1ß and Tumor Necrosis Factor-α) release and activation of osteoclastogenesis. Furthermore, our data suggest that GD monocytes would display an increased osteoclastogenic potential, independent of their interaction with the GD microenvironment or other GD cells. Both proinflammatory cytokine production and osteoclastogenesis were restored at least, in part, by treating cells with the recombinant human GCase, a substrate synthase inhibitor, a pharmacological chaperone, and an anti-inflammatory compound. Besides confirming that this model would be suitable to perform high-throughput screening of therapeutic molecules that act via different mechanisms and on different phenotypic features, our data provided insights into the pathogenic cascade, leading to osteoclastogenesis exacerbation and its contribution to bone pathology in GD.

Distribution of Exonic Variants in Glycogen Synthesis and Catabolism Genes in Late Onset Pompe Disease (LOPD).

Pompe disease (PD) is a monogenic autosomal recessive disorder caused by biallelic pathogenic variants of the GAA gene encoding lysosomal alpha-glucosidase; its loss causes glycogen storage in lysosomes, mainly in the muscular tissue. The genotype-phenotype correlation has been extensively discussed, and caution is recommended when interpreting the clinical significance of any mutation in a single patient. As there is no evidence that environmental factors can modulate the phenotype, the observed clinical variability in PD suggests that genetic variants other than pathogenic GAA mutations influence the mechanisms of muscle damage/repair and the overall clinical picture. Genes encoding proteins involved in glycogen synthesis and catabolism may represent excellent candidates as phenotypic modifiers of PD. The genes analyzed for glycogen synthesis included UGP2, glycogenin (GYG1-muscle, GYG2, and other tissues), glycogen synthase (GYS1-muscle and GYS2-liver), GBE1, EPM2A, NHLRC1, GSK3A, and GSK3B. The only enzyme involved in glycogen catabolism in lysosomes is α-glucosidase, which is encoded by GAA, while two cytoplasmic enzymes, phosphorylase (PYGB-brain, PGL-liver, and PYGM-muscle) and glycogen debranching (AGL) are needed to obtain glucose 1-phosphate or free glucose. Here, we report the potentially relevant variants in genes related to glycogen synthesis and catabolism, identified by whole exome sequencing in a group of 30 patients with late-onset Pompe disease (LOPD). In our exploratory analysis, we observed a reduced number of variants in the genes expressed in muscles versus the genes expressed in other tissues, but we did not find a single variant that strongly affected the phenotype. From our work, it also appears that the current clinical scores used in LOPD do not describe muscle impairment with enough qualitative/quantitative details to correlate it with genes that, even with a slightly reduced function due to genetic variants, impact the phenotype.

First experience of combined enzyme replacement therapy and hematopoietic stem cell transplantation in alpha-mannosidosis.

We describe the first case of bridge therapy in alpha-mannosidosis (AM) in an infant diagnosed at only 5 months of life who underwent enzyme replacement therapy (ERT) in the pre- and peri-transplant phases. Eight ERT infusions were administered before hematopoietic stem cell transplantation (HSCT) and continued for additional 90 days until complete engraftment. The clinical and laboratory data after 3 years post-HSCT show that the early combined intervention may reduce the disease progression and the urine and plasma content of mannosyl-oligosaccharides (OS) monitored by liquid chromatography tandem mass spectrometry (LC-MS/MS). This report highlights that early diagnosis and prompt initiation of such treatments in AM are the best chance to minimize the progression of symptoms.

Consensus clinical management guidelines for acid sphingomyelinase deficiency (Niemann-Pick disease types A, B and A/B).

BACKGROUND: Acid Sphingomyelinase Deficiency (ASMD) is a rare autosomal recessive disorder caused by mutations in the SMPD1 gene. This rarity contributes to misdiagnosis, delayed diagnosis and barriers to good care. There are no published national or international consensus guidelines for the diagnosis and management of patients with ASMD. For these reasons, we have developed clinical guidelines that defines standard of care for ASMD patients. METHODS: The information contained in these guidelines was obtained through a systematic literature review and the experiences of the authors in their care of patients with ASMD. We adopted the Appraisal of Guidelines for Research and Evaluation (AGREE II) system as method of choice for the guideline development process. RESULTS: The clinical spectrum of ASMD, although a continuum, varies substantially with subtypes ranging from a fatal infantile neurovisceral disorder to an adult-onset chronic visceral disease. We produced 39 conclusive statements and scored them according to level of evidence, strengths of recommendations and expert opinions. In addition, these guidelines have identified knowledge gaps that must be filled by future research. CONCLUSION: These guidelines can inform care providers, care funders, patients and their carers about best clinical practice and leads to a step change in the quality of care for patients with ASMD with or without enzyme replacement therapy (ERT).

Mucopolysaccharidoses Differential Diagnosis by Mass Spectrometry-Based Analysis of Urine Free Glycosaminoglycans-A Diagnostic Prediction Model.

Impaired glycosaminoglycans (GAGs) catabolism may lead to a cluster of rare metabolic and genetic disorders called mucopolysaccharidoses (MPSs). Each subtype is caused by the deficiency of one of the lysosomal hydrolases normally degrading GAGs. Affected tissues accumulate undegraded GAGs in cell lysosomes and in the extracellular matrix, thus leading to the MPS complex clinical phenotype. Although each MPS may present with recognizable signs and symptoms, these may often overlap between subtypes, rendering the diagnosis difficult and delayed. Here, we performed an exploratory analysis to develop a model that predicts MPS subtypes based on UHPLC-MS/MS measurement of a urine free GAG profile (or GAGome). We analyzed the GAGome of 78 subjects (38 MPS, 37 healthy and 3 with other MPS symptom-overlapping disorders) using a standardized kit in a central-blinded laboratory. We observed several MPS subtype-specific GAGome changes. We developed a multivariable penalized Lasso logistic regression model that attained 91.2% balanced accuracy to distinguish MPS type II vs. III vs. any other subtype vs. not MPS, with sensitivity and specificity ranging from 73.3% to 91.7% and from 98.4% to 100%, depending on the predicted subtype. In conclusion, the urine GAGome was revealed to be useful in accurately discriminating the different MPS subtypes with a single UHPLC-MS/MS run and could serve as a reliable diagnostic test for a more rapid MPS biochemical diagnosis.

Clinical disease characteristics of patients with Niemann-Pick Disease Type C: findings from the International Niemann-Pick Disease Registry (INPDR).

BACKGROUND: Niemann-Pick Disease Type C (NPC) is an autosomal recessive rare disease characterised by progressive neurovisceral manifestations. The collection of on-going large-scale NPC clinical data may generate better understandings of the natural history of the disease. Here we report NPC patient data from the International Niemann-Pick Disease Registry (INPDR). METHOD: The INPDR is a web-based, patient-led independent registry for the collection of prospective and retrospective clinical data from Niemann-Pick Disease patients. Baseline data from NPC patients enrolled into the INPDR from September 2014 to December 2019 was extracted to analyse the demographic, genetic and clinical features of the disease. RESULTS: A total of 203 NPC patients from six European countries were included in this study. The mean age (SD) at diagnosis was 11.2 years (14.2). Among enrolled patients, 168 had known neurological manifestations: 43 (24.2%) had early-infantile onset, 47 (26.4%) had late-infantile onset, 41 (23.0%) had juvenile onset, and 37 (20.8%) had adult onset. 10 (5.6%) patients had the neonatal rapidly fatal systemic form. Among the 97 patients with identified NPC1 variants, the most common variant was the c. 3182T > C variant responsible for the p.lle1061Thr protein change, reported in 35.1% (N = 34) of patients. The frequencies of hepatomegaly and neonatal jaundice were greatest in patients with early-infantile and late-infantile neurological onset. Splenomegaly was the most commonly reported observation, including 80% of adult-onset patients. The most commonly reported neurological manifestations were cognitive impairment (78.5%), dysarthria (75.9%), ataxia (75.9%), vertical supranuclear gaze palsy (70.9%) and dysphagia (69.6%). A 6-domain composite disability scale was used to calculate the overall disability score for each neurological form. Across all with neurological onset, the majority of patients showed moderate to severe impairments in all domains, except for 'swallowing' and 'seizure'. The age at diagnosis and death increased with increased age of neurological symptom onset. Miglustat use was recorded in 62.4% of patients and the most common symptomatic therapies used by patients were antiepileptics (32.9%), antidepressants (11.8%) and antacids (9.4%). CONCLUSION: The proportion of participants at each age of neurological onset was relatively equal across the cohort. Neurological manifestations, such as ataxia, dysphagia, and dysarthria, were frequently observed across all age categories.

Acid Sphingomyelinase Deficiency: A Clinical and Immunological Perspective.

Acid sphingomyelinase deficiency (ASMD) is a lysosomal storage disease caused by deficient activity of acid sphingomyelinase (ASM) enzyme, leading to the accumulation of varying degrees of sphingomyelin. Lipid storage leads to foam cell infiltration in tissues, and clinical features including hepatosplenomegaly, pulmonary insufficiency and in some cases central nervous system involvement. ASM enzyme replacement therapy is currently in clinical trial being the first treatment addressing the underlying pathology of the disease. Therefore, presently, it is critical to better comprehend ASMD to improve its diagnose and monitoring. Lung disease, including recurrent pulmonary infections, are common in ASMD patients. Along with lung disease, several immune system alterations have been described both in patients and in ASMD animal models, thus highlighting the role of ASM enzyme in the immune system. In this review, we summarized the pivotal roles of ASM in several immune system cells namely on macrophages, Natural Killer (NK) cells, NKT cells, B cells and T cells. In addition, an overview of diagnose, monitoring and treatment of ASMD is provided highlighting the new enzyme replacement therapy available.

Focal hepatic lesions in acid sphingomyelinase deficiency: Differential diagnosis between foamy macrophages aggregates and malignancy.

Acid sphingomyelinase deficiency (ASMD) is a rare metabolic disorder due to biallelic mutation in the SMPD1 gene. The defect leads to the accumulation of sphingomyelin within the cells of the reticulo-endothelial system, particularly in the spleen, liver, lungs, and bone marrow causing hepato-splenomegaly, lung disease and hematological abnormalities. At present, data on abdominal imaging in ASMD are limited. Here we describe the characteristics of focal liver lesions observed in a 30 years old female. During the Magnetic Resonance follow up an increase in number and size of the lesions, showing T1 hypointensity and T2 hyperintensity with contrast enhancement, was observed. Contrast enhanced ultrasound evidenced rapid wash-in and steady isoecogenicity without appreciable wash-out at 80 seconds. The main lesion was biopsied to rule out the presence of a hepatocellular carcinoma, and showed to be a benign foamy macrophages aggregate. In this report, we discuss the possible pathogenesis of focal hepatic lesions in ASMD and their differential diagnosis.

Plasma Neurofilament Light (NfL) in Patients Affected by Niemann-Pick Type C Disease (NPCD).

(1) Background: Niemann-Pick type C disease (NPCD) is an autosomal recessive lysosomal storage disorder caused by mutations in the NPC1 or NPC2 genes. The clinical presentation is characterized by visceral and neurological involvement. Apart from a small group of patients presenting a severe perinatal form, all patients develop progressive and fatal neurological disease with an extremely variable age of onset. Different biomarkers have been identified; however, they poorly correlate with neurological disease. In this study we assessed the possible role of plasma NfL as a neurological disease-associated biomarker in NPCD. (2) Methods: Plasma NfL levels were measured in 75 healthy controls and 26 patients affected by NPCD (24 NPC1 and 2 NPC2; 39 samples). (3) Results: Plasma NfL levels in healthy controls correlated with age and were significantly lower in pediatric patients as compared to adult subjects (p = 0.0017). In both pediatric and adult NPCD patients, the plasma levels of NfL were significantly higher than in age-matched controls (p < 0.0001). Most importantly, plasma NfL levels in NPCD patients with neurological involvement were significantly higher than the levels found in patients free of neurological signs at the time of sampling, both in the pediatric and the adult group (p = 0.0076; p = 0.0032, respectively). Furthermore, in adults the NfL levels in non-neurological patients were comparable with those found in age-matched controls. No correlations between plasma NfL levels and NPCD patient age at sampling or plasma levels of cholestan 3ß-5α-6ß-triol were found. (4) Conclusions: These data suggest a promising role of plasma NfL as a possible neurological disease-associated biomarker in NPCD.

Accurate Molecular Diagnosis of Gaucher Disease Using Clinical Exome Sequencing as a First-Tier Test.

Gaucher disease (GD) is an autosomal recessive lysosomal disorder due to beta-glucosidase gene (GBA) mutations. The molecular diagnosis of GD is complicated by the presence of recombinant alleles originating from a highly homologous pseudogene. Clinical exome sequencing (CES) is a rapid genetic approach for identifying disease-causing mutations. However, copy number variation and recombination events are poorly detected, and further investigations are required to avoid mis-genotyping. The aim of this work was to set-up an integrated strategy for GD patients genotyping using CES as a first-line test. Eight patients diagnosed with GD were analyzed by CES. Five patients were fully genotyped, while three were revealed to be homozygous for mutations that were not confirmed in the parents. Therefore, MLPA (multiplex ligation-dependent probe amplification) and specific long-range PCR were performed, and two recombinant alleles, one of them novel, and one large deletion were identified. Furthermore, an MLPA assay performed in one family resulted in the identification of an additional novel mutation (p.M124V) in a relative, in trans with the known p.N409S mutation. In conclusion, even though CES has become extensively used in clinical practice, our study emphasizes the importance of a comprehensive molecular strategy to provide proper GBA genotyping and genetic counseling.

Expression of the tumor-expressed protein MageB2 enhances rRNA transcription.

An essential requirement for cells to sustain a high proliferating rate is to be paired with enhanced protein synthesis through the production of ribosomes. For this reason, part of the growth-factor signaling pathways, are devoted to activate ribosome biogenesis. Enhanced production of ribosomes is a hallmark in cancer cells, which is boosted by different mechanisms. Here we report that the nucleolar tumor-protein MageB2, whose expression is associated with cell proliferation, also participates in ribosome biogenesis. Studies carried out in both siRNA-mediated MageB2 silenced cells and CRISPR/CAS9-mediated MageB2 knockout (KO) cells showed that its expression is linked to rRNA transcription increase independently of the cell proliferation status. Mechanistically, MageB2 interacts with phospho-UBF, a protein which causes the recruitment of RNA Pol I pre-initiation complex required for rRNA transcription. In addition, cells expressing MageB2 displays enhanced phospho-UBF occupancy at the rDNA gene promoter. Proteomic studies performed in MageB2 KO cells revealed impairment in ribosomal protein (RPs) content. Functionally, enhancement in rRNA production in MageB2 expressing cells, was directly associated with an increased dynamic in protein synthesis. Altogether our results unveil a novel function for a tumor-expressed protein from the MAGE-I family. Findings reported here suggest that nucleolar MageB2 might play a role in enhancing ribosome biogenesis as part of its repertoire to support cancer cell proliferation.

Deferoxamine mesylate improves splicing and GAA activity of the common c.-32-13T>G allele in late-onset PD patient fibroblasts.

Pompe disease (PD) is an autosomal recessive lysosomal storage disorder due to deficient activity of the acid alpha glucosidase enzyme (GAA). As a consequence of the enzymatic defect, undigested glycogen accumulates within lysosomes. Most patients affected by the late-onset (LO) phenotype carry in at least one allele the c.-32-13T>G variant, which leads to exon 2 exclusion from the pre-mRNA. These patients display a variable and suboptimal response to enzyme replacement therapy. To identify novel therapeutic approaches, we developed a fluorescent GAA exon 2 splicing assay and screened a library of US Food and Drug Administration (FDA)-approved compounds. This led to the identification of several drugs able to restore normal splicing. Among these, we further validated the effects of the iron chelator deferoxamine (Defe) in c.-32-13T>G fibroblasts. Defe treatment resulted in a 2-fold increase of GAA exon 2 inclusion and a 40% increase in enzymatic activity. Preliminary results suggest that this effect is mediated by the regulation of iron availability, at least partially. RNA-seq experiments also showed that Defe might shift the balance of splicing factor levels toward a profile promoting GAA exon 2 inclusion. This work provides the basis for drug repurposing and development of new chemically modified molecules aimed at improving the clinical outcome in LO-PD patients.

In vitro and in vivo effects of Ambroxol chaperone therapy in two Italian patients affected by neuronopathic Gaucher disease and epilepsy.

Gaucher disease (GD) is an autosomal recessive lysosomal storage disorder caused by mutations in the acid ß-glucosidase encoding gene (GBA1), resulting in the deficient activity of acid ß-glucosidase (GCase). To date, there is no approved treatment for the neurological manifestations of the disease. The role of Ambroxol as a chaperone for mutant GCase has been extensively demonstrated in vitro. Furthermore, different authors have reported beneficial effects of high doses of Ambroxol on neurological manifestations in patients affected by GD. In this report, we describe the in vitro and in vivo effects of Ambroxol in two patients (P1 and P2) affected by the neurological form of GD and epilepsy, carrying mutations already reported as responsive to the chaperone. Indeed, P1 presented the N188S mutation in compound heterozygous with a null allele (IVS2 + 1G > A) and P2 was homozygous for the L444P mutation. As expected, a beneficial effect of Ambroxol was observed in cultured fibroblasts as well as in vivo, both on epilepsy and on biomarkers of GD, in P1. However, Ambroxol was completely undefective in P2, suggesting that other factors besides the GBA1 mutation itself would be involved in the response therapy which would be difficult to predict based on the patient genotype. The present report expands the experience of Ambroxol treatment in neurological GD patients and highlights the need to in vitro test the individual response to Ambroxol even in patients carrying mutations already classified as responsive to the chaperone.

Early biochemical effects of velmanase alfa in a 7-month-old infant with alpha-mannosidosis.

Alpha mannosidosis is an ultrarare pathology with variable phenotypic manifestations, characterized by the deficiency of lysosomal alpha mannosidase which causes accumulation of neutral oligosaccharides. Until recently, the hematopoietic stem cell transplantation was the only clinical feasible therapeutic option. Only in 2018, the European Medicines Agency's committee approved the recombinant enzyme velmanase alfa for long-term treatment of non-neurological manifestations in mild and moderate forms of alpha-mannosidosis. In this study, the very early biochemical effects of enzyme replacement therapy in in a 7-month-old patient with alpha-mannosidosis were described. Velmanase alpha was administered as supporting therapy awaiting for hematopoietic stem cell transplantation, the treatment chosen for the patient because of the early onset form. The results showed that the enzyme replacement therapy was able to reduce the content of three different mannosyl-oligosaccharides monitored by tandem mass spectrometry after 2 months of treatment. In particular, the mean relative changes from baseline values were -67% in urine and -53% in serum at the latest observation. The study also showed that the enzymatic activity detected in serum 1 week after the first infusion was four times higher than the normal values and constant in the following points of observation. These findings led us to assume that velmanase alfa might be biologically active in this young patient.

Exercise training alone or in combination with high-protein diet in patients with late onset Pompe disease: results of a cross over study.

BACKGROUND: Late onset Pompe disease (LOPD) is a lysosomal neuromuscular disorder which can progressively impair the patients' exercise tolerance, motor and respiratory functions, and quality of life. The available enzyme replacement therapy (ERT) does not completely counteract disease progression. We investigated the effect of exercise training alone, or associated with a high-protein diet, on the exercise tolerance, muscle and pulmonary functions, and quality of life of LOPD patients on long term ERT. METHODS: The patients were asked to participate to a crossover randomized study comprehending a control period (free diet, no exercise) followed by 2 intervention periods: exercise or exercise + diet, each lasting 26 weeks and separated by 13 weeks washout periods. Exercise training included moderate-intensity aerobic exercise on a cycle ergometer, stretching and balance exercises, strength training. The diet was composed by 25-30% protein, 30-35% carbohydrate and 35-40% fat. Before and after each period patients were assessed for: exercise tolerance test on a cycle-ergometer, serum muscle enzymes, pulmonary function tests and SF36 questionnaire for quality of life. Compliance was evaluated by training and dietary diaries. Patients were contacted weekly by researchers to optimize adherence to treatments. RESULTS: Thirteen LOPD patients, median age 49 ± 11 years, under chronic ERT (median 6.0 ± 4.0 years) were recruited. Peak aerobic power (peak pulmonary O2 uptake) decreased after control, whereas it increased after exercise, and more markedlyafter exercise + diet. Serum levels of lactate dehydrogenase (LDH) significantly decreased after exercise + diet; both creatine kinase (CK) and LDH levels were significantly reduced after exercise + diet compared to exercise. Pulmonary function showed no changes after control and exercise, whereas a significant improvement of forced expiratory volume in 1 sec (FEV1) was observed after exercise + diet. SF36 showed a slight improvement in the "mental component" scale after exercise, and a significant improvement in "general health" and "vitality" after exercise + diet. The compliance to prescriptions was higher than 70% for both diet and exercise. CONCLUSIONS: Exercise tolerance (as evaluated by peak aerobic power) showed a tendency to decrease in LOPD patients on long term ERT. Exercise training, particularly if combined with high-protein diet, could reverse this decrease and result in an improvement, which was accompanied by improved quality of life. The association of the two lifestyle interventions resulted also in a reduction of muscle enzyme levels and improved pulmonary function.

Pre-mRNA splicing defects and RNA binding protein involvement in Niemann Pick type C disease.

Niemann-Pick type C (NPC) is an autosomal recessive lysosomal storage disorder due to mutations in NPC1 (95 % cases) or NPC2 genes, encoding NPC1 and NPC2 proteins, respectively. Both NPC1 and NPC2 proteins are involved in transport of intracellular cholesterol and their alteration leads to the accumulation of unesterified cholesterol and other lipids within the lysosomes. The disease is characterized by visceral, neurological and psychiatric symptoms. However, the pathogenic mechanisms that lead to the fatal neurodegeneration are still unclear. To date, several mutations leading to the generation of aberrant splicing variants or mRNA degradation in NPC1 and NPC2 genes have been reported. In addition, different lines of experimental evidence have highlighted the possible role of RNA-binding proteins and RNA-metabolism, in the onset and progression of many neurodegenerative disorders, that could explain NPC neurological features and in general, the disease pathogenesis. In this review, we will provide an overview of the impact of mRNA processing and metabolism on NPC disease pathology.