Pathological 25 kDa C-Terminal Fragments of TDP-43 Are Present in Lymphoblastoid Cell Lines and Extracellular Vesicles from Patients Affected by Frontotemporal Lobar Degeneration and Neuronal Ceroidolipofuscinosis Carrying a GRN Mutation.

Frontotemporal lobar degeneration (FTLD) is a complex disease, characterized by progressive degeneration of frontal and temporal lobes. Mutations in progranulin (GRN) gene have been found in up to 50% of patients with familial FTLD. Abnormal deposits of post-translationally-modified TAR DNA-binding protein of 43 kDa (TDP-43) represent one of the main hallmarks of the brain pathology. To investigate in peripheral cells the presence of the different TDP-43 forms, especially the toxic 25 kDa fragments, we analyzed lymphoblastoid cell lines (LCLs) and the derived extracellular vesicles (EVs) from patients carrying a GRN mutation, together with wild-type (WT) healthy controls. After characterizing EV sizes and concentrations by nanoparticle tracking analysis, we investigated the levels of different forms of the TDP-43 protein in LCLs and respective EVs by Western blot. Our results showed a trend of concentration decreasing in EVs derived from GRN-mutated LCLs, although not reaching statistical significance. A general increase in p-TDP-43 levels in GRN-mutated LCLs and EVs was observed. In particular, the toxic 25 kDa fragments of p-TDP-43 were only present in GRN-mutated LCLs and were absent in the WT controls. Furthermore, these fragments appeared to be more concentrated in EVs than in LCLs, suggesting a relevant role of EVs in spreading pathological molecules between cells.

Plasma Small Extracellular Vesicle Cathepsin D Dysregulation in GRN/C9orf72 and Sporadic Frontotemporal Lobar Degeneration.

Emerging data suggest the roles of endo-lysosomal dysfunctions in frontotemporal lobar degeneration (FTLD) and in other dementias. Cathepsin D is one of the major lysosomal proteases, mediating the degradation of unfolded protein aggregates. In this retrospective study, we investigated cathepsin D levels in human plasma and in the plasma small extracellular vesicles (sEVs) of 161 subjects (40 sporadic FTLD, 33 intermediate/pathological C9orf72 expansion carriers, 45 heterozygous/homozygous GRN mutation carriers, and 43 controls). Cathepsin D was quantified by ELISA, and nanoparticle tracking analysis data (sEV concentration for the cathepsin D level normalization) were extracted from our previously published dataset or were newly generated. First, we revealed a positive correlation of the cathepsin D levels with the age of the patients and controls. Even if no significant differences were found in the cathepsin D plasma levels, we observed a progressive reduction in plasma cathepsin D moving from the intermediate to C9orf72 pathological expansion carriers. Observing the sEVs nano-compartment, we observed increased cathepsin D sEV cargo (ng/sEV) levels in genetic/sporadic FTLD. The diagnostic performance of this biomarker was fairly high (AUC = 0.85). Moreover, sEV and plasma cathepsin D levels were positively correlated with age at onset. In conclusion, our study further emphasizes the common occurrence of endo-lysosomal dysregulation in GRN/C9orf72 and sporadic FTLD.

Singular cases of Alzheimer's disease disclose new and old genetic "acquaintances".

BACKGROUND: Alzheimer's disease (AD) is the most common age-related dementia. Besides its typical presentation with amnestic syndrome at onset, atypical AD cases are being increasingly recognized, often in presenile age. OBJECTIVES: To provide an extensive clinical and genetic characterization of six AD patients carrying one or more singular features, including age of onset, atypical phenotype and disease progression rate. By reviewing the pertinent literature and accessing publicly available databases, we aimed to assess the frequency and the significance of the identified genetic variants. METHODS: Biomarkers of amyloid-ß deposition and neurodegeneration were used to establish the in vivo diagnosis of probable AD, in addition to neurological and neuropsychological evaluation, extensive laboratory assays and neuroradiological data. Considering the presenile onset of the majority of the cases, we hypothesized genetically determined AD and performed extensive genetic analyses by both Sanger sequencing and next generation sequencing (NGS). RESULTS: We disclosed two known missense variants, one in PSEN1 and the other in PSEN2, and a novel silent variant in PSEN2. Most notably, we identified several additional variants in other dementia-related genes by NGS. Some of them have never been reported in any control or disease databases, representing variants unique to our cases. CONCLUSIONS: This work underlines the difficulties in reaching a confident in vivo diagnosis in cases of atypical dementia. Moreover, a wider genetic analysis by NGS approach may prove to be useful in specific cases, especially when the study of the so-far known AD causative genes produces negative or conflicting results.

Clinical and Genetic Heterogeneity in a Large Family with Pseudoxanthoma Elasticum: MTHFR and SERPINE1 Variants as Possible Disease Modifiers in Developing Ischemic Stroke.

BACKGROUND AND OBJECTIVES: Pseudoxanthoma elasticum (PXE) is a rare autosomal recessive disorder caused by pathogenic variants in the ABCC6 gene. The phenotypic spectrum of PXE is highly variable and includes principally three major features: skin lesions, eye and vascular manifestations, while brain manifestations are less common. To date about 400 different PXE associated variants in ABCC6 gene are described without any evident genotype-phenotype correlation. Herein, we report the clinical and molecular findings of a large PXE family with clinical and genetic intra-familial variability with significant cerebrovascular involvement. METHODS: The analysis of the ABCC6 gene was performed in the proband and her familiars for the definition of genetic background. Then, in order to determine why some affected individuals had more prominent brain involvement, we investigated classic thrombophilic gene variants. RESULTS: Molecular findings disclosed two different ABCC6 mutations, i.e., the recurrent p.(Arg518Gln) and the novel p.(Val1285Met) missense substitution responsible of a pseudo-dominant inheritance. The study of thrombophilic gene variants revealed the presence of 4G/4G SERPINE1 genotype in the proband and in her father, which both developed ischemic stroke. The proband carried also the C677T variant the MTHFR gene. CONCLUSION: We argue, for the first time, that the 4G/4G SERPINE1 genotype could represent an additional risk factor in PXE for developing ischemic stroke, which adds up to the already known predisposing conditions. Therapeutic implications are discussed, we also advise that PXE patients should be adequately screened for cerebral vasculopathy, even more if familial history is suggestive of brain complications.

Expanding the spectrum of SPTLC1-related disorders beyond hereditary sensory and autonomic neuropathies: A novel case of the distinct "S331 syndrome".

Hereditary sensory and autonomic neuropathies (HSAN) encompass a group of peripheral nervous system disorders characterized by remarkable heterogeneity from a clinical and genetic point of view. Mutations in SPTLC1 gene are responsible for HSAN type IA, which usually starts from the second to fourth decade with axonal neuropathy, sensory loss, painless distal ulcerations, and mild autonomic features, while motor involvement usually occur later as disease progresses. Beyond the classic presentation of HSAN type IA, an exceedingly rare distinct phenotype related to SPTLC1 mutations at residue serine 331 (S331) has recently been reported, characterized by earlier onset, prominent muscular atrophy, growth retardation, oculo-skeletal abnormalities, and possible respiratory complications. In this report, we describe clinical, instrumental, and genetic aspects of a 13-year-old Sri Lankan male carrying the rare de novo p.S331Y heterozygous mutation in SPTLC1 gene found by whole exome sequencing. Patient's phenotype partly overlaps with the first case previously reported, however with some additional features not described before. This work represent the second report about this rare mutation and our findings strongly reinforce the hypothesis of a clearly distinct "S331 syndrome", thus expanding the spectrum of SPTLC1-related disorders.

Human prion diseases: surgical lessons learned from iatrogenic prion transmission.

The human prion diseases, or transmissible spongiform encephalopathies, have captivated our imaginations since their discovery in the Fore linguistic group in Papua New Guinea in the 1950s. The mysterious and poorly understood "infectious protein" has become somewhat of a household name in many regions across the globe. From bovine spongiform encephalopathy (BSE), commonly identified as mad cow disease, to endocannibalism, media outlets have capitalized on these devastatingly fatal neurological conditions. Interestingly, since their discovery, there have been more than 492 incidents of iatrogenic transmission of prion diseases, largely resulting from prion-contaminated growth hormone and dura mater grafts. Although fewer than 9 cases of probable iatrogenic neurosurgical cases of Creutzfeldt-Jakob disease (CJD) have been reported worldwide, the likelihood of some missed cases and the potential for prion transmission by neurosurgery create considerable concern. Laboratory studies indicate that standard decontamination and sterilization procedures may be insufficient to completely remove infectivity from prion-contaminated instruments. In this unfortunate event, the instruments may transmit the prion disease to others. Much caution therefore should be taken in the absence of strong evidence against the presence of a prion disease in a neurosurgical patient. While the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) have devised risk assessment and decontamination protocols for the prevention of iatrogenic transmission of the prion diseases, incidents of possible exposure to prions have unfortunately occurred in the United States. In this article, the authors outline the historical discoveries that led from kuru to the identification and isolation of the pathological prion proteins in addition to providing a brief description of human prion diseases and iatrogenic forms of CJD, a brief history of prion disease nosocomial transmission, and a summary of the CDC and WHO guidelines for prevention of prion disease transmission and decontamination of prion-contaminated neurosurgical instruments.

Heidenhain variant in two patients with inherited V210I Creutzfeldt-Jakob disease.

OBJECTIVE: To report two members of the same family carrying the valine to isoleucine point mutation of the prion protein gene (PRNP) and presenting with visual symptoms as initial manifestation as in the "Heidenhain variant" of sporadic Creutzfeldt-Jakob disease (CJD). METHODS: Patients underwent neurological examination, electroencephalogram (EEG), brain magnetic resonance images (MRI) and cerebrospinal fluid (CSF) analysis including the Real Time Quaking Induced Conversion (RT-QuIC) test. Disease-specific mutations and polymorphism at codon 129 of the PRNP gene were also studied. RESULTS: Isolated visual symptoms characterized disease onset of both patients followed by progressive neurological signs, dementia and death in 3 (proband) and 9 (his aunt) months. RT-QuIC analysis of CSF samples of both patients revealed the presence of the pathological prion protein and DNA analysis the V210I point mutation of the PRNP and methionine homozygosity at the polymorphic codon 129. CONCLUSIONS: This report suggests to consider the diagnosis of V210I genetic CJD in patients presenting with the Heidenhain form of CJD and highlights the importance of genetic testing in all patients with isolated visual manifestations at onset followed by progressive neurological signs and dementia.

Sporadic Creutzfeldt-Jakob disease in a native Puerto Rican patient.

The diagnosis of Creutzfeldt-Jakob disease (CJD) is often a challenge for most physicians given its extremely low incidence and different clinico-pathological presentations. We report the case of a 56-year old patient native to Puerto Rico suspected of sporadic Creutzfeldt-Jakob disease (sCD). The symptoms at onset were notorious for bilateral cortical blindness followed by rapidly progressive cognitive decline, visual deficit, increased levels of CSF 14-3-3 and tau along with positive brain MRI and EEG, are highly indicative of CJD. The definite diagnosis was confirmed by the National Prion Disease Pathology Surveillance Center (NPDPSC), in Cleveland, Ohio, USA. Lack of genetic mutations in the prion protein (PrP) gene, widespread histopathological changes and the accumulation of scrapie PrP (PrPSc) in the brain confirmed the diagnosis of sCJD. The patient, admitted to our institution in 2011, represents the first detailed report of sCJD in a native Puerto Rican patient living in Puerto Rico.

Novel histotypes of sporadic Creutzfeldt-Jakob disease linked to 129MV genotype.

The MV1 and MV2 subtypes of sporadic Creutzfeldt-Jakob disease (sCJD) are linked to the heterozygous methionine (M)/valine (V) polymorphism at codon 129 of the prion protein (PrP) gene. MV2 is phenotypically heterogeneous, whereas MV1, due to its low prevalence, is one of the least well characterized subtypes. In this study, we investigated the biochemical properties of PrPSc and phenotypic expression of cases diagnosed as sCJD MV1 and MV2. We describe four MV2 histotypes: 2C, with cortical (C) coarse pathology; 2K, with kuru (K) plaque deposits; 2C-K, with co-existing C and K histotypic features; and the novel histotype 2C-PL that mimics 2C in the cerebral cortex and cerebellum, but exhibits plaque-like (PL) PrP deposits in subcortical regions (e.g., basal nuclei, thalamus and midbrain). Histotype prevalence is highest for 2C-K (55%), intermediate for 2C (31%), and lowest for 2C-PL and 2K (7%). Nearly every MV2 case expressed both PrPSc types, with T2 being the predominant type ("MV2-1"). MV1 cases typically show a rapid disease course (≤ 4 months), and feature the 1C histotype, phenotypically identical to sCJDMM1. Co-existing PrPSc types, with T1 significantly exceeding T2 ("MV1-2"), are detected in patients diagnosed as MV1 with longer disease courses. We observed four histotypes among MV1-2 cases, including two novel histotypes: 1V, reminiscent of sCJDVV1; 1C-2C, resembling sCJDMM1-2 with predominant MM1 histotypic component; and novel histotypes 1C-2PL and 1C-2K, overall mimicking 1C in the cerebral cortex, but harboring T2 and plaque-like PrP deposits in subcortical regions (1C-2PL), and T2 and kuru plaques in the cerebellum (1C-2K). Lesion profiles of 1C, 1V, and 1C-2C are similar, but differ from 1C-2PL and 1C-2K, as the latter two groups show prominent hippocampal and nigral degeneration. We believe that the novel "C-PL" histotypes are distinct entities rather than intermediate forms between "C" and "C-K" groups, and that 1C-2PL and 1C-2K histotypes may be characterized by different T1 variants of the same size.

Alemtuzumab-Related Lymphocyte Subset Dynamics and Disease Activity or Autoimmune Adverse Events: Real-World Evidence.

BACKGROUND AND OBJECTIVES: alemtuzumab is a monoclonal anti-CD52 antibody acting on B and T cells in highly active multiple sclerosis (MS). We analyzed changes in lymphocyte subsets after alemtuzumab administration in relation to disease activity and autoimmune adverse events. METHODS: lymphocyte subset counts were assessed longitudinally using linear mixed models. Subset counts at baseline and during follow-up were correlated with relapse rate, adverse events, or magnetic resonance (MRI) activity. RESULTS: we recruited 150 patients followed for a median of 2.7 years (IQR: 1.9-3.7). Total lymphocytes, CD4, CD8, and CD20 significantly decreased in all patients over 2 years (p < 0.001). Previous treatment with fingolimod increased the risk of disease activity and adverse events (p = 0.029). We found a higher probability of disease reactivation in males and in patients with over three active lesions at baseline. Higher EDSS scores at baseline and longer disease duration predicted the switch to other treatments after alemtuzumab. DISCUSSION AND CONCLUSIONS: Our real-world study supports data from clinical trials in which lymphocyte subsets were not useful for predicting disease activity or autoimmune disease during treatment. The early use of an induction therapy such as alemtuzumab in patients with a lower EDSS score and short history of disease could mitigate the risk of treatment failure.

Amyloid-beta42 interacts mainly with insoluble prion protein in the Alzheimer brain.

The prion protein (PrP) is best known for its association with prion diseases. However, a controversial new role for PrP in Alzheimer disease (AD) has recently emerged. In vitro studies and mouse models of AD suggest that PrP may be involved in AD pathogenesis through a highly specific interaction with amyloid-ß (Aß42) oligomers. Immobilized recombinant human PrP (huPrP) also exhibited high affinity and specificity for Aß42 oligomers. Here we report the novel finding that aggregated forms of huPrP and Aß42 are co-purified from AD brain extracts. Moreover, an anti-PrP antibody and an agent that specifically binds to insoluble PrP (iPrP) co-precipitate insoluble Aß from human AD brain. Finally, using peptide membrane arrays of 99 13-mer peptides that span the entire sequence of mature huPrP, two distinct types of Aß binding sites on huPrP are identified in vitro. One specifically binds to Aß42 and the other binds to both Aß42 and Aß40. Notably, Aß42-specific binding sites are localized predominantly in the octapeptide repeat region, whereas sites that bind both Aß40 and Aß42 are mainly in the extreme N-terminal or C-terminal domains of PrP. Our study suggests that iPrP is the major PrP species that interacts with insoluble Aß42 in vivo. Although this work indicated the interaction of Aß42 with huPrP in the AD brain, the pathophysiological relevance of the iPrP/Aß42 interaction remains to be established.

Is the pathology of posterior cortical atrophy clinically predictable?

Posterior cortical atrophy (PCA) is a neurodegenerative disorder characterized by an early prominent deficit of visual functions associated with signs and symptoms that are the expression of dysfunction of posterior brain regions. Although PCA is commonly associated with Alzheimer's disease (AD), in recent years new pathological substrates have emerged. Among them, frontotemporal lobar degeneration (FTLD) is the most commonly reported but, to date, little is known about the clinical features of PCA due to FTLD. We conducted a systematic search in the main biomedical database MEDLINE. We searched for all clinical PCA reports that assessed the pathological basis of such syndrome with at least one of the following: (1) neuropathological examination, (2) cerebrospinal fluid biomarkers, (3) amyloid-PET imaging and (4) genetic testing. Of 369 potentially eligible studies, 40 fulfilled the inclusion criteria with an overall number of 144 patients (127 PCA-AD vs. 17 PCA-FTD/non-AD). We found that hallucinations/illusions were present in none of the probable PCA-FTD/non-AD subjects while were reported in 15 out of 97 PCA-AD individuals. Optic ataxia and Parkinsonism showed a significantly greater prevalence in probable PCA FTD/non-AD than in PCA-AD whereas myoclonus and disorientation in time and space were significantly more frequent in PCA-AD than in probable PCA FTD/non-AD. We also found a predominance of a left-side pattern of atrophy/hypometabolism in the probable PCA FTD/non-AD. Clinical features such as optic ataxia, Parkinsonism, myoclonus, hallucinations and disorientation in time and space suggest the underlying pathological basis of PCA and help in leading the diagnostic protocol consequently.

Systematic Review on the Role of Lobar Cerebral Microbleeds in Cognition.

BACKGROUND: Cerebral microbleeds (CMBs) are small round/oval lesions seen in MRI-specific sequences. They are divided in deep and lobar according to their location. Lobar CMBs (L-CMBs) are commonly associated with amyloid angiopathy. Although CMBs have been considered clinically silent for a long time, a growing body of evidence has shown that they could play a crucial role in cognitive functioning. OBJECTIVE: The aim of this systematic review was to estimate the role of L-CMBs in cognitive performance. METHODS: We selected, from the Cochrane Library, Embase, PubMed, and ScienceDirect databases, clinical studies, published from January 2000 to January 2020 and focused on the association between L-CMBs and cognitive functions. The inclusion criteria were: 1) participants grouped according to presence or absence of CMBs, 2) extensive neuropsychological examination, 3) CMBs differentiation according to topographical distribution, and 4) MRI-based CMB definition (< 10 mm and low signal in T2*/SWI). The impact of L-CMBs was separately assessed for executive functions, visuospatial skills, language, and memory. RESULTS: Among 963 potentially eligible studies, six fulfilled the inclusion criteria. Four studies reported a greater reduction in executive performances in participants with L-CMB and two studies showed a statistically significant association between visuospatial dysfunction and L-CMBs. No association was found between hippocampal memory or language abilities and L-CMBs. CONCLUSION: Lobar CMBs are associated with a reduction of processing speed and visuospatial performances, thus suggesting the contribution of vascular amyloid deposition to this cognitive profile. This occurrence enables us to suspect an underlying Alzheimer's disease pathology even in absence of typical hippocampal memory impairment.

Plasma Small Extracellular Vesicles with Complement Alterations in GRN/C9orf72 and Sporadic Frontotemporal Lobar Degeneration.

Cutting-edge research suggests endosomal/immune dysregulation in GRN/C9orf72-associated frontotemporal lobar degeneration (FTLD). In this retrospective study, we investigated plasma small extracellular vesicles (sEVs) and complement proteins in 172 subjects (40 Sporadic FTLD, 40 Intermediate/Pathological C9orf72 expansion carriers, and 49 Heterozygous/Homozygous GRN mutation carriers, 43 controls). Plasma sEVs (concentration, size) were analyzed by nanoparticle tracking analysis; plasma and sEVs C1q, C4, C3 proteins were quantified by multiplex assay. We demonstrated that genetic/sporadic FTLD share lower sEV concentrations and higher sEV sizes. The diagnostic performance of the two most predictive variables (sEV concentration/size ratio) was high (AUC = 0.91, sensitivity 85.3%, specificity 81.4%). C1q, C4, and C3 cargo per sEV is increased in genetic and sporadic FTLD. C4 (cargo per sEV, total sEV concentration) is increased in Sporadic FTLD and reduced in GRN+ Homozygous, suggesting its specific unbalance compared with Heterozygous cases. C3 plasma level was increased in genetic vs. sporadic FTLD. Looking at complement protein compartmentalization, in control subjects, the C3 and C4 sEV concentrations were roughly half that in respect to those measured in plasma; interestingly, this compartmentalization was altered in different ways in patients. These results suggest sEVs and complement proteins as potential therapeutic targets to mitigate neurodegeneration in FTLD.

Variably protease-sensitive prionopathy: a new sporadic disease of the prion protein.

OBJECTIVE: The objective of the study is to report 2 new genotypic forms of protease-sensitive prionopathy (PSPr), a novel prion disease described in 2008, in 11 subjects all homozygous for valine at codon 129 of the prion protein (PrP) gene (129VV). The 2 new PSPr forms affect individuals who are either homozygous for methionine (129MM) or heterozygous for methionine/valine (129MV). METHODS: Fifteen affected subjects with 129MM, 129MV, and 129VV underwent comparative evaluation at the National Prion Disease Pathology Surveillance Center for clinical, histopathologic, immunohistochemical, genotypical, and PrP characteristics. RESULTS: Disease duration (between 22 and 45 months) was significantly different in the 129VV and 129MV subjects. Most other phenotypic features along with the PrP electrophoretic profile were similar but distinguishable in the 3 129 genotypes. A major difference laid in the sensitivity to protease digestion of the disease-associated PrP, which was high in 129VV but much lower, or altogether lacking, in 129MV and 129MM. This difference prompted the substitution of the original designation with "variably protease-sensitive prionopathy" (VPSPr). None of the subjects had mutations in the PrP gene coding region. INTERPRETATION: Because all 3 129 genotypes are involved, and are associated with distinguishable phenotypes, VPSPr becomes the second sporadic prion protein disease with this feature after Creutzfeldt-Jakob disease, originally reported in 1920. However, the characteristics of the abnormal prion protein suggest that VPSPr is different from typical prion diseases, and perhaps more akin to subtypes of Gerstmann-Sträussler-Scheinker disease.

Characterization of Prion Disease Associated with a Two-Octapeptide Repeat Insertion.

Genetic prion disease accounts for 10-15% of prion disease. While insertion of four or more octapeptide repeats are clearly pathogenic, smaller repeat insertions have an unclear pathogenicity. The goal of this case series was to provide an insight into the characteristics of the 2-octapeptide repeat genetic variant and to provide insight into the risk for Creutzfeldt-Jakob disease in asymptomatic carriers. 2-octapeptide repeat insertion prion disease cases were collected from the National Prion Disease Pathology Surveillance Center (US), the National Prion Clinic (UK), and the National Creutzfeldt-Jakob Disease Registry (Australia). Three largescale population genetic databases were queried for the 2-octapeptide repeat insertion allele. Eight cases of 2-octapeptide repeat insertion were identified. The cases were indistinguishable from the sporadic Creutzfeldt-Jakob cases of the same molecular subtype. Western blot characterization of the prion protein in the absence of enzymatic digestion with proteinase K revealed that 2-octapeptide repeat insertion and sporadic Creutzfeldt-Jakob disease have distinct prion protein profiles. Interrogation of large-scale population datasets suggested the variant is of very low penetrance. The 2-octapeptide repeat insertion is at most a low-risk genetic variant. Predictive genetic testing for asymptomatic blood relatives is not likely to be justified given the low risk.

A novel missense mutation in CAV3 gene in an Italian family with persistent hyperCKemia, myalgia and hypercholesterolemia: Double-trouble.

Caveolins are essential proteins in caveolae architecture, small plasma membrane invaginations that play a key role in a variety of cellular processes, including vesicular trafficking and signal transduction. Mutations in the gene encoding caveolin-3 (CAV3) cause a broad spectrum of clinical phenotypes, ranging from isolated hyperCKemia to most severe limb girdle muscular dystrophy and cardiomyopathy. We report a novel heterozygous p.Val44Met (c.130G > A) CAV3 mutation in two brothers presenting with persistent elevation of serum creatine kinase, myalgia and hypercholesterolemia. Immunofluorescence study with anticaveolin-3 antibodies on muscle biopsy of the proband confirmed a reduced immuno-reactivity of caveolin-3 on the sarcolemma. This findings support the pathogenic effect of this novel mutation and extend the genotypic and clinical spectrum of Caveolinopathies. Finally, we discuss the hypothesis that the association between CAV3 mutations and hypercholesterolemia may not be coincidental.