Publications by authors named "Chiara Fiorillo"

96 Publications

An integrated approach to the evaluation of patients with asymptomatic or minimally symptomatic hyperCKemia.

Muscle Nerve 2021 Oct 23. Epub 2021 Oct 23.

Department of Neurosciences, Rehabilitation, Ophthalmology, Genetic and Maternal and Infantile Sciences (DINOGMI), University of Genova, Unit of Neurology, IRCCS Ospedale Policlinico San Martino, Genova, Italy.

Introduction/aims: Currently, there are no straightforward guidelines for the clinical and diagnostic management of hyperCKemia, a frequent and nonspecific presentation in muscle diseases. Therefore, we aimed to describe our diagnostic workflow for evaluating patients with this condition.

Methods: We selected 83 asymptomatic or minimally symptomatic patients with persistent hyperCKemia for participation in this Italian multicenter study. Patients with facial involvement and distal or congenital myopathies were excluded, as were patients with suspected inflammatory myopathies or predominant respiratory or cardiac involvement. All patients underwent a neurological examination and nerve conduction and electromyography studies. The first step of the investigation included a screening for Pompe disease. We then evaluated the patients for myotonic dystrophy type II-related CCTG expansion and excluded patients with copy number variations in the DMD gene. Subsequently, the undiagnosed patients were investigated using a target gene panel that included 20 genes associated with isolated hyperCKemia.

Results: Using this approach, we established a definitive diagnosis in one third of the patients. The detection rate was higher in patients with severe hyperCKemia and abnormal electromyographic findings.

Discussion: We have described our diagnostic workflow for isolated hyperCKemia, which is based on electrodiagnostic data, biochemical screening, and first-line genetic investigations, followed by successive targeted sequencing panels. Both clinical signs and electromyographic abnormalities are associated with increased diagnostic yields. This article is protected by copyright. All rights reserved.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mus.27446DOI Listing
October 2021

An integrated approach to the evaluation of patients with asymptomatic or minimally symptomatic hyperCKemia.

Muscle Nerve 2021 Oct 23. Epub 2021 Oct 23.

Department of Neurosciences, Rehabilitation, Ophthalmology, Genetic and Maternal and Infantile Sciences (DINOGMI), University of Genova, Unit of Neurology, IRCCS Ospedale Policlinico San Martino, Genova, Italy.

Introduction/aims: Currently, there are no straightforward guidelines for the clinical and diagnostic management of hyperCKemia, a frequent and nonspecific presentation in muscle diseases. Therefore, we aimed to describe our diagnostic workflow for evaluating patients with this condition.

Methods: We selected 83 asymptomatic or minimally symptomatic patients with persistent hyperCKemia for participation in this Italian multicenter study. Patients with facial involvement and distal or congenital myopathies were excluded, as were patients with suspected inflammatory myopathies or predominant respiratory or cardiac involvement. All patients underwent a neurological examination and nerve conduction and electromyography studies. The first step of the investigation included a screening for Pompe disease. We then evaluated the patients for myotonic dystrophy type II-related CCTG expansion and excluded patients with copy number variations in the DMD gene. Subsequently, the undiagnosed patients were investigated using a target gene panel that included 20 genes associated with isolated hyperCKemia.

Results: Using this approach, we established a definitive diagnosis in one third of the patients. The detection rate was higher in patients with severe hyperCKemia and abnormal electromyographic findings.

Discussion: We have described our diagnostic workflow for isolated hyperCKemia, which is based on electrodiagnostic data, biochemical screening, and first-line genetic investigations, followed by successive targeted sequencing panels. Both clinical signs and electromyographic abnormalities are associated with increased diagnostic yields. This article is protected by copyright. All rights reserved.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mus.27448DOI Listing
October 2021

The Role of Muscle Biopsy in Diagnostic Process of Infant Hypotonia: From Clinical Classification to the Genetic Outcome.

Front Neurol 2021 5;12:735488. Epub 2021 Oct 5.

Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.

The role of muscle biopsy in the diagnostic workup of floppy infants is controversial. Muscle sampling is invasive, and often, results are not specific. The rapid expansion of genetic approach has made the muscle histopathology analysis less crucial. This study aims to assess the role and efficacy of muscle histopathology in the diagnostic algorithm of hypotonia in early infancy through a retrospective analysis of 197 infants who underwent muscle biopsy in their first 18 months of life. Data analysis revealed that 92/197 (46.7%) of muscle biopsies were non-specific (80) or normal (12), not allowing a specific diagnosis. In 41/197 (20.8%) cases, biopsy suggested a metabolic or mitochondrial myopathy, while in 23/197 cases (11.7%), we found evidence of muscular dystrophy. In 19/197 cases (9.7%), histopathology characteristics of a congenital myopathy were reported. In 22/197 cases (11.7%), the histopathological study indicated presence of a neurogenic damage. Overall, 46 diagnoses were then achieved by oriented genetic tests. Muscle biopsy results were consistent with genetic results in 90% of cases. Diagnostic algorithms for the diagnosis of a floppy infant are largely missing. Muscle biopsy alone can lead to a diagnosis, help the clinician in the choice of a genetic test, or even modify a diagnosis made previously.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fneur.2021.735488DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8523832PMC
October 2021

Monoallelic KIF1A-related disorders: a multicenter cross sectional study and systematic literature review.

J Neurol 2021 Sep 6. Epub 2021 Sep 6.

Neurofisiopathology Unit, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168, Rome, Italy.

Background: Monoallelic variants in the KIF1A gene are associated with a large set of clinical phenotypes including neurodevelopmental and neurodegenerative disorders, underpinned by a broad spectrum of central and peripheral nervous system involvement.

Methods: In a multicenter study conducted in patients presenting spastic gait or complex neurodevelopmental disorders, we analyzed the clinical, genetic and neuroradiological features of 28 index cases harboring heterozygous variants in KIF1A. We conducted a literature systematic review with the aim to comparing our findings with previously reported KIF1A-related phenotypes.

Results: Among 28 patients, we identified nine novel monoallelic variants, and one a copy number variation encompassing KIF1A. Mutations arose de novo in most patients and were prevalently located in the motor domain. Most patients presented features of a continuum ataxia-spasticity spectrum with only five cases showing a prevalently pure spastic phenotype and six presenting congenital ataxias. Seventeen mutations occurred in the motor domain of the Kinesin-1A protein, but location of mutation did not correlate with neurological and imaging presentations. When tested in 15 patients, muscle biopsy showed oxidative metabolism alterations (6 cases), impaired respiratory chain complexes II + III activity (3/6) and low CoQ10 levels (6/9). Ubiquinol supplementation (1gr/die) was used in 6 patients with subjective benefit.

Conclusions: This study broadened our clinical, genetic, and neuroimaging knowledge of KIF1A-related disorders. Although highly heterogeneous, it seems that manifestations of ataxia-spasticity spectrum disorders seem to occur in most patients. Some patients also present secondary impairment of oxidative metabolism; in this subset, ubiquinol supplementation therapy might be appropriate.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00415-021-10792-3DOI Listing
September 2021

NGS in Hereditary Ataxia: When Rare Becomes Frequent.

Int J Mol Sci 2021 Aug 6;22(16). Epub 2021 Aug 6.

Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Stella Maris Foundation, 56128 Pisa, Italy.

The term hereditary ataxia (HA) refers to a heterogeneous group of neurological disorders with multiple genetic etiologies and a wide spectrum of ataxia-dominated phenotypes. Massive gene analysis in next-generation sequencing has entered the HA scenario, broadening our genetic and clinical knowledge of these conditions. In this study, we employed a targeted resequencing panel (TRP) in a large and highly heterogeneous cohort of 377 patients with a clinical diagnosis of HA, but no molecular diagnosis on routine genetic tests. We obtained a positive result (genetic diagnosis) in 33.2% of the patients, a rate significantly higher than those reported in similar studies employing TRP (average 19.4%), and in line with those performed using exome sequencing (ES, average 34.6%). Moreover, 15.6% of the patients had an uncertain molecular diagnosis. , , and were the most common causative genes. A comparison with published literature data showed that our panel would have identified 97% of the positive cases reported in previous TRP-based studies and 92% of those diagnosed by ES. Proper use of multigene panels, when combined with detailed phenotypic data, seems to be even more efficient than ES in clinical practice.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms22168490DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8395181PMC
August 2021

The Diagnostic Approach to Mitochondrial Disorders in Children in the Era of Next-Generation Sequencing: A 4-Year Cohort Study.

J Clin Med 2021 Jul 22;10(15). Epub 2021 Jul 22.

Department of Molecular Medicine, IRCCS Stella Maris Foundation, 56128 Pisa, Italy.

Mitochondrial diseases (MDs) are a large group of genetically determined multisystem disorders, characterized by extreme phenotypic heterogeneity, attributable in part to the dual genomic control (nuclear and mitochondrial DNA) of the mitochondrial proteome. Advances in next-generation sequencing technologies over the past two decades have presented clinicians with a challenge: to select the candidate disease-causing variants among the huge number of data provided. Unfortunately, the clinical tools available to support genetic interpretations still lack specificity and sensitivity. For this reason, the diagnosis of MDs continues to be difficult, with the new "genotype first" approach still failing to diagnose a large group of patients. With the aim of investigating possible relationships between clinical and/or biochemical phenotypes and definitive molecular diagnoses, we performed a retrospective multicenter study of 111 pediatric patients with clinical suspicion of MD. In this cohort, the strongest predictor of a molecular (in particular an mtDNA-related) diagnosis of MD was neuroimaging evidence of basal ganglia (BG) involvement. Regression analysis confirmed that normal BG imaging predicted negative genetic studies for MD. Psychomotor regression was confirmed as an independent predictor of a definitive diagnosis of MD. The findings of this study corroborate previous data supporting a role for neuroimaging in the diagnostic approach to MDs and reinforce the idea that mtDNA sequencing should be considered for first-line testing, at least in specific groups of children.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/jcm10153222DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8348083PMC
July 2021

Neuromuscular and Neuroendocrinological Features Associated With -Related Arthrogryposis Multiplex Congenita in a Sicilian Family: A Case Report.

Front Neurol 2021 12;12:704747. Epub 2021 Jul 12.

Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.

Wieacker-Wolff syndrome (WWS) is an X-linked Arthrogryposis Multiplex Congenita (AMC) disorder associated with broad neurodevelopmental impairment. The genetic basis of WWS lies in hemizygous pathogenic variants in , encoding a C4H2 type zinc-finger nuclear factor abundantly expressed in the developing human brain. The main clinical features described in WWS families carrying pathogenic variants encompass having a short stature, microcephaly, birth respiratory distress, arthrogryposis, hypotonia, distal muscle weakness, and broad neurodevelopmental delay. We hereby report a Sicilian family with a boy clinically diagnosed with WWS and genetically investigated with exome sequencing (ES), leading to the identification of a c.593G>A (p. R198Q) hemizygous pathogenic variant in the gene. During the first year of life, the onset of central hypoadrenalism led to recurrent hypoglycemic events, which likely contributed to seizure susceptibility. Also, muscle biopsy studies confirmed a pathology of the muscle tissue and revealed peculiar abnormalities of the neuromuscular junction. In conclusion, we expand the phenotypic spectrum of the WWS-related neurodevelopmental disorders and discuss the role of in the context of the potential neuroendocrinological and neuromuscular features associated with this condition.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fneur.2021.704747DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8313121PMC
July 2021

New phenotype caused by POMGNT2 mutations.

BMJ Case Rep 2021 Jul 22;14(7). Epub 2021 Jul 22.

Pediatrics and Neonatology Department, Ospedale Maggiore di Modica, Nino Baglieri, ASP Ragusa, Ragusa, Sicilia, Italy.

We present a case report about a Moroccan 3-year-old girl, with an intermediate phenotype of muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 8 form. We performed clinical and instrumental evaluation, muscle biopsy, genetic screening of 59 genes for different cerebral malformations, follow-up and review of literature. After investigations, we identified an intermediate new phenotype between the severe and mild form, characterised by significant malformations of the cortex with myopatic symptoms, this increases the genotype-phenotype correlation knowledge about POMGNT2 gene mutations. New homozygous missense mutation on POMGNT2 (c.511 G>A, p.Asp171Asn, rs768063378) was detected.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/bcr-2021-242358DOI Listing
July 2021

Muscle inflammatory pattern in alpha- and gamma-sarcoglycanopathies.

Clin Neuropathol 2021 Jul 20. Epub 2021 Jul 20.

Aim: Since the immune system plays a role in the pathogenesis of several muscular dystrophies, we aim to characterize several muscular inflammatory features in α- (LGMD R3) and γ-sarcoglycanopathies (LGMD R5).

Materials And Methods: We explored the expression of major histocompatibility complex class I molecules (MHCI), and we analyzed the composition of the immune infiltrates in muscle biopsies from 10 patients with LGMD R3 and 8 patients with LGMD R5, comparing the results to Duchenne muscular dystrophy patients (DMD).

Results: A consistent involvement of the immune response was observed in sarcoglycanopathies, although it was less evident than in DMD. LGMD R3-R5 and DMD shared an abnormal expression of MHCI, and the composition of the muscular immune cell infiltrate was comparable.

Conclusion: These findings might serve as a rationale to fine-tune a disease-specific immunomodulatory regimen, particularly relevant in view of the rapid development of gene therapy for sarcoglycanopathies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5414/NP301393DOI Listing
July 2021

Movement Disorders in Children with a Mitochondrial Disease: A Cross-Sectional Survey from the Nationwide Italian Collaborative Network of Mitochondrial Diseases.

J Clin Med 2021 May 12;10(10). Epub 2021 May 12.

IRCCS Fondazione Stella Maris, 56018 Pisa, Italy.

Movement disorders are increasingly being recognized as a manifestation of childhood-onset mitochondrial diseases (MDs). However, the spectrum and characteristics of these conditions have not been studied in detail in the context of a well-defined cohort of patients. We retrospectively explored a cohort of individuals with childhood-onset MDs querying the Nationwide Italian Collaborative Network of Mitochondrial Diseases database. Using a customized online questionnaire, we attempted to collect data from the subgroup of patients with movement disorders. Complete information was available for 102 patients. Movement disorder was the presenting feature of MD in 45 individuals, with a mean age at onset of 11 years. Ataxia was the most common movement disorder at onset, followed by dystonia, tremor, hypokinetic disorders, chorea, and myoclonus. During the disease course, most patients (67.7%) encountered a worsening of their movement disorder. Basal ganglia involvement, cerebral white matter changes, and cerebellar atrophy were the most commonly associated neuroradiological patterns. Forty-one patients harbored point mutations in the mitochondrial DNA, 10 carried mitochondrial DNA rearrangements, and 41 cases presented mutations in nuclear-DNA-encoded genes, the latter being associated with an earlier onset and a higher impairment in activities of daily living. Among our patients, 32 individuals received pharmacological treatment; clonazepam and oral baclofen were the most commonly used drugs, whereas levodopa and intrathecal baclofen administration were the most effective. A better delineation of the movement disorders phenotypes starting in childhood may improve our diagnostic workup in MDs, fine tuning management, and treatment of affected patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/jcm10102063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8151313PMC
May 2021

Childhood amyotrophic lateral sclerosis caused by excess sphingolipid synthesis.

Nat Med 2021 Jul 31;27(7):1197-1204. Epub 2021 May 31.

Department of Neurology, Hereditary Neuropathy Foundation Center of Excellence, Neuroscience Institute, Hackensack University Medical Center, Hackensack Meridian School of Medicine, Hackensack, NJ, USA.

Amyotrophic lateral sclerosis (ALS) is a progressive, neurodegenerative disease of the lower and upper motor neurons with sporadic or hereditary occurrence. Age of onset, pattern of motor neuron degeneration and disease progression vary widely among individuals with ALS. Various cellular processes may drive ALS pathomechanisms, but a monogenic direct metabolic disturbance has not been causally linked to ALS. Here we show SPTLC1 variants that result in unrestrained sphingoid base synthesis cause a monogenic form of ALS. We identified four specific, dominantly acting SPTLC1 variants in seven families manifesting as childhood-onset ALS. These variants disrupt the normal homeostatic regulation of serine palmitoyltransferase (SPT) by ORMDL proteins, resulting in unregulated SPT activity and elevated levels of canonical SPT products. Notably, this is in contrast with SPTLC1 variants that shift SPT amino acid usage from serine to alanine, result in elevated levels of deoxysphingolipids and manifest with the alternate phenotype of hereditary sensory and autonomic neuropathy. We custom designed small interfering RNAs that selectively target the SPTLC1 ALS allele for degradation, leave the normal allele intact and normalize sphingolipid levels in vitro. The role of primary metabolic disturbances in ALS has been elusive; this study defines excess sphingolipid biosynthesis as a fundamental metabolic mechanism for motor neuron disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41591-021-01346-1DOI Listing
July 2021

Biallelic variants in LIG3 cause a novel mitochondrial neurogastrointestinal encephalomyopathy.

Brain 2021 06;144(5):1451-1466

Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, 611-0011, Japan.

Abnormal gut motility is a feature of several mitochondrial encephalomyopathies, and mutations in genes such as TYMP and POLG, have been linked to these rare diseases. The human genome encodes three DNA ligases, of which only one, ligase III (LIG3), has a mitochondrial splice variant and is crucial for mitochondrial health. We investigated the effect of reduced LIG3 activity and resulting mitochondrial dysfunction in seven patients from three independent families, who showed the common occurrence of gut dysmotility and neurological manifestations reminiscent of mitochondrial neurogastrointestinal encephalomyopathy. DNA from these patients was subjected to whole exome sequencing. In all patients, compound heterozygous variants in a new disease gene, LIG3, were identified. All variants were predicted to have a damaging effect on the protein. The LIG3 gene encodes the only mitochondrial DNA (mtDNA) ligase and therefore plays a pivotal role in mtDNA repair and replication. In vitro assays in patient-derived cells showed a decrease in LIG3 protein levels and ligase activity. We demonstrated that the LIG3 gene defects affect mtDNA maintenance, leading to mtDNA depletion without the accumulation of multiple deletions as observed in other mitochondrial disorders. This mitochondrial dysfunction is likely to cause the phenotypes observed in these patients. The most prominent and consistent clinical signs were severe gut dysmotility and neurological abnormalities, including leukoencephalopathy, epilepsy, migraine, stroke-like episodes, and neurogenic bladder. A decrease in the number of myenteric neurons, and increased fibrosis and elastin levels were the most prominent changes in the gut. Cytochrome c oxidase (COX) deficient fibres in skeletal muscle were also observed. Disruption of lig3 in zebrafish reproduced the brain alterations and impaired gut transit in vivo. In conclusion, we identified variants in the LIG3 gene that result in a mitochondrial disease characterized by predominant gut dysmotility, encephalopathy, and neuromuscular abnormalities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/brain/awab056DOI Listing
June 2021

Functional analysis of p.ser605del variant: the aging phenotype of MDPL syndrome is associated with an impaired DNA repair capacity.

Aging (Albany NY) 2021 02 22;13(4):4926-4945. Epub 2021 Feb 22.

Department of Biomedicine and Prevention, Tor Vergata University, Rome 00133, Italy.

Mandibular hypoplasia, Deafness and Progeroid features with concomitant Lipodystrophy define a rare systemic disorder, named MDPL Syndrome, due to almost always a variant in gene, encoding the DNA polymerase δ. We report a MDPL female heterozygote for the recurrent p.Ser605del variant. In order to deepen the functional role of the in frame deletion affecting the polymerase catalytic site of the protein, cellular phenotype has been characterised. MDPL fibroblasts exhibit nuclear envelope anomalies, accumulation of prelamin A and presence of micronuclei. A decline of cell growth, cellular senescence and a blockage of proliferation in G0/G1 phase complete the aged cellular picture. The evaluation of the genomic instability reveals a delayed recovery from DNA induced-damage. Moreover, the rate of telomere shortening was greater in pathological cells, suggesting the telomere dysfunction as an emerging key feature in MDPL. Our results suggest an alteration in DNA replication/repair function of as a primary pathogenetic cause of MDPL. The understanding of the mechanisms linking these cellular characteristics to the accelerated aging and to the wide spectrum of affected tissues and clinical symptoms in the MDPL patients may provide opportunities to develop therapeutic treatments for progeroid syndromes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18632/aging.202680DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7950258PMC
February 2021

Musculoskeletal Features without Ataxia Associated with a Novel de novo Mutation in Impairing the Voltage Sensitivity of Kv1.1 Channel.

Biomedicines 2021 Jan 14;9(1). Epub 2021 Jan 14.

Paediatric Neurology and Neuromuscular Disorders Unit, IRCCS Institute "G. Gaslini", 80131 Genoa, Italy.

The gene encodes the α subunit of the voltage-gated Kv1.1 potassium channel that critically regulates neuronal excitability in the central and peripheral nervous systems. Mutations in have been classically associated with episodic ataxia type 1 (EA1), a movement disorder triggered by physical and emotional stress. Additional features variably reported in recent years include epilepsy, myokymia, migraine, paroxysmal dyskinesia, hyperthermia, hypomagnesemia, and cataplexy. Interestingly, a few individuals with neuromyotonia, either isolated or associated with skeletal deformities, have been reported carrying variants in the S2-S3 transmembrane segments of Kv1.1 channels in the absence of any other symptoms. Here, we have identified by whole-exome sequencing a novel de novo variant, T268K, in in a boy displaying recurrent episodes of neuromyotonia, muscle hypertrophy, and skeletal deformities. Through functional analysis in heterologous cells and structural modeling, we show that the mutation, located at the extracellular end of the S3 helix, causes deleterious effects, disrupting Kv1.1 function by altering the voltage dependence of activation and kinetics of deactivation, likely due to abnormal interactions with the voltage sensor in the S4 segment. Our study supports previous evidence suggesting that specific residues within the S2 and S3 segments of Kv1.1 result in a distinctive phenotype with predominant musculoskeletal presentation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/biomedicines9010075DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7829709PMC
January 2021

Maintenance treatment with subcutaneous immunoglobulins in the long-term management of anti-HMCGR myopathy.

Neuromuscul Disord 2021 02 28;31(2):134-138. Epub 2020 Dec 28.

Department of Neurosciences, Rehabilitation, Ophthalmology, Genetic and Maternal and Infantile Sciences (DINOGMI), University of Genova, Largo P. Daneo3, 16132 Genova, Italy; IRCCS Ospedale Policlinico San Martino, Genova, Italy. Electronic address:

We describe the clinical response to long-term subcutaneous immunoglobulins (SCIg) in anti-3‑hydroxy-3-methyl-glutaryl-coenzyme-A-reductase (anti-HMCGR) myopathy previously treated with intravenous immunoglobulins (IVIg). We collected data from patients affected by anti-HMGCR myopathy, switched from IVIg to SCIg therapy, after achieving clinical stabilization. The Medical Research Council sum score, creatine kinase (CK) levels, and anti-HMGCR antibodies were used to assess the response. We identified three patients with anti-HMGCR myopathy treated with SCIg with a favourable clinical course, allowing the maintenance of clinical stability, the reduction or suspension of steroids therapy and in two of them a complete CK normalization. Finally, anti-HMGCR antibodies tested in all patients after 12 months from SCIg starting, showed a global decrease. SCIg represent an useful alternative to long-term IVIg as already well known in several autoimmune neuromuscular disorders and inflammatory myopathies with advantages of lower side effects and home self-administration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.nmd.2020.12.012DOI Listing
February 2021

Pathogenic Variants in the Myosin Chaperone UNC-45B Cause Progressive Myopathy with Eccentric Cores.

Am J Hum Genet 2020 12 19;107(6):1078-1095. Epub 2020 Nov 19.

Department of Clinical Genome Analysis, Medical Genome Center, National Center of Neurology and Psychiatry, 187-8551 Tokyo, Japan.

The myosin-directed chaperone UNC-45B is essential for sarcomeric organization and muscle function from Caenorhabditis elegans to humans. The pathological impact of UNC-45B in muscle disease remained elusive. We report ten individuals with bi-allelic variants in UNC45B who exhibit childhood-onset progressive muscle weakness. We identified a common UNC45B variant that acts as a complex hypomorph splice variant. Purified UNC-45B mutants showed changes in folding and solubility. In situ localization studies further demonstrated reduced expression of mutant UNC-45B in muscle combined with abnormal localization away from the A-band towards the Z-disk of the sarcomere. The physiological relevance of these observations was investigated in C. elegans by transgenic expression of conserved UNC-45 missense variants, which showed impaired myosin binding for one and defective muscle function for three. Together, our results demonstrate that UNC-45B impairment manifests as a chaperonopathy with progressive muscle pathology, which discovers the previously unknown conserved role of UNC-45B in myofibrillar organization.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajhg.2020.11.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7820787PMC
December 2020

Genotype-phenotype correlations in recessive titinopathies.

Genet Med 2020 12 11;22(12):2029-2040. Epub 2020 Aug 11.

Department of Neurosciences, Nerve-Muscle Unit, Lausanne University Hospital (CHUV), 1011, Lausanne, Switzerland.

Purpose: High throughput sequencing analysis has facilitated the rapid analysis of the entire titin (TTN) coding sequence. This has resulted in the identification of a growing number of recessive titinopathy patients. The aim of this study was to (1) characterize the causative genetic variants and clinical features of the largest cohort of recessive titinopathy patients reported to date and (2) to evaluate genotype-phenotype correlations in this cohort.

Methods: We analyzed clinical and genetic data in a cohort of patients with biallelic pathogenic or likely pathogenic TTN variants. The cohort included both previously reported cases (100 patients from 81 unrelated families) and unreported cases (23 patients from 20 unrelated families).

Results: Overall, 132 causative variants were identified in cohort members. More than half of the cases had hypotonia at birth or muscle weakness and a delayed motor development within the first 12 months of life (congenital myopathy) with causative variants located along the entire gene. The remaining patients had a distal or proximal phenotype and a childhood or later (noncongenital) onset. All noncongenital cases had at least one pathogenic variant in one of the final three TTN exons (362-364).

Conclusion: Our findings suggest a novel association between the location of nonsense variants and the clinical severity of the disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41436-020-0914-2DOI Listing
December 2020

Randomized phase 2 trial and open-label extension of domagrozumab in Duchenne muscular dystrophy.

Neuromuscul Disord 2020 06 19;30(6):492-502. Epub 2020 May 19.

University of Massachusetts Medical School, Worcester, MA, USA.

We report results from a phase 2, randomized, double-blind, 2-period trial (48 weeks each) of domagrozumab and its open-label extension in patients with Duchenne muscular dystrophy (DMD). Of 120 ambulatory boys (aged 6 to <16 years) with DMD, 80 were treated with multiple ascending doses (5, 20, and 40 mg/kg) of domagrozumab and 40 treated with placebo. The primary endpoints were safety and mean change in 4-stair climb (4SC) time at week 49. Secondary endpoints included other functional tests, pharmacokinetics, and pharmacodynamics. Mean (SD) age was 8.4 (1.7) and 9.3 (2.3) years in domagrozumab- and placebo-treated patients, respectively. Difference in mean (95% CI) change from baseline in 4SC at week 49 for domagrozumab vs placebo was 0.27 (-7.4 to 7.9) seconds (p = 0.94). There were no significant between-group differences in any secondary clinical endpoints. Most patients had ≥1 adverse event in the first 48 weeks; most were mild and not treatment-related. Median serum concentrations of domagrozumab increased with administered dose within each dose level. Non-significant increases in muscle volume were observed in domagrozumab- vs placebo-treated patients. Domagrozumab was generally safe and well tolerated in patients with DMD. Efficacy measures did not support a significant treatment effect. Clinicaltrials.gov identifiers: NCT02310763 and NCT02907619.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.nmd.2020.05.002DOI Listing
June 2020

Optic Atrophy and Generalized Chorea in a Patient Harboring an OPA10/RTN4IP1 Pathogenic Variant.

Neuropediatrics 2020 12 11;51(6):425-429. Epub 2020 May 11.

Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal, and Child Health, University of Genoa, Genoa, Italy.

pathogenic variants (OPA10 syndrome) have been described in patients with early-onset recessive optic neuropathy and recently associated with a broader clinical spectrum, from isolated optic neuropathy to severe encephalopathies with epilepsy. Here we present a case of a patient with a complex clinical picture characterized by bilateral optic nerve atrophy, horizontal nystagmus, myopia, mild intellectual disability, generalized chorea, isolated small subependymal heterotopia, and asynchronous self-resolving midbrain MRI (magnetic resonance imaging) lesions. By using massive gene sequencing, we identified in this patient the c.308G > A (p.Arg103His) homozygous pathogenic variant in the gene. Complex movement disorders and relapsing-remitting neuroradiological lesions have not been previously reported in this condition. Our case expands the clinical spectrum of OPA10 syndrome and opens new opportunities for the molecular diagnosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1055/s-0040-1708539DOI Listing
December 2020

Interpretation of the Epigenetic Signature of Facioscapulohumeral Muscular Dystrophy in Light of Genotype-Phenotype Studies.

Int J Mol Sci 2020 Apr 10;21(7). Epub 2020 Apr 10.

Department of Clinical and Experimental Medicine, University of Messina, 98124 Messina, Italy.

Facioscapulohumeral muscular dystrophy (FSHD) is characterized by incomplete penetrance and intra-familial clinical variability. The disease has been associated with the genetic and epigenetic features of the D4Z4 repetitive elements at 4q35. Recently, D4Z4 hypomethylation has been proposed as a reliable marker in the FSHD diagnosis. We exploited the Italian Registry for FSHD, in which FSHD families are classified using the Clinical Comprehensive Evaluation Form (CCEF). A total of 122 index cases showing a classical FSHD phenotype (CCEF, category A) and 110 relatives were selected to test with the receiver operating characteristic (ROC) curve, the diagnostic and predictive value of D4Z4 methylation. Moreover, we performed DNA methylation analysis in selected large families with reduced penetrance characterized by the co-presence of subjects carriers of one D4Z4 reduced allele with no signs of disease or presenting the classic FSHD clinical phenotype. We observed a wide variability in the D4Z4 methylation levels among index cases revealing no association with clinical manifestation or disease severity. By extending the analysis to family members, we revealed the low predictive value of D4Z4 methylation in detecting the affected condition. In view of the variability in D4Z4 methylation profiles observed in our large cohort, we conclude that D4Z4 methylation does not mirror the clinical expression of FSHD. We recommend that measurement of this epigenetic mark must be interpreted with caution in clinical practice.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms21072635DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7178248PMC
April 2020

The Genetic Landscape of Dystrophin Mutations in Italy: A Nationwide Study.

Front Genet 2020 3;11:131. Epub 2020 Mar 3.

Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.

Dystrophinopathies are inherited diseases caused by mutations in the dystrophin () gene for which testing is mandatory for genetic diagnosis, reproductive choices and eligibility for personalized trials. We genotyped the gene in our Italian cohort of 1902 patients (BMD n = 740, 39%; DMD n =1162, 61%) within a nationwide study involving 11 diagnostic centers in a 10-year window (2008-2017). In DMD patients, we found deletions in 57%, duplications in 11% and small mutations in 32%. In BMD, we found deletions in 78%, duplications in 9% and small mutations in 13%. In BMD, there are a higher number of deletions, and small mutations are more frequent than duplications. Among small mutations that are generally frequent in both phenotypes, 44% of DMD and 36% of BMD are nonsense, thus, eligible for stop codon read-through therapy; 63% of all out-of-frame deletions are eligible for single exon skipping. Patients were also assigned to Italian regions and showed interesting regional differences in mutation distribution. The full genetic characterization in this large, nationwide cohort has allowed us to draw several correlations between DMD/BMD genotype landscapes and mutation frequency, mutation types, mutation locations along the gene, exon/intron architecture, and relevant protein domain, with effects on population genetic characteristics and new personalized therapies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fgene.2020.00131DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7063120PMC
March 2020

Distal motor neuropathy associated with novel EMILIN1 mutation.

Neurobiol Dis 2020 04 21;137:104757. Epub 2020 Jan 21.

Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy; Paediatric Neurology and Neuromuscular Disorders Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy. Electronic address:

Elastin microfibril interface-located proteins (EMILINs) are extracellular matrix glycoproteins implicated in elastogenesis and cell proliferation. Recently, a missense mutation in the EMILIN1 gene has been associated with autosomal dominant connective tissue disorder and motor-sensory neuropathy in a single family. We identified by whole exome sequencing a novel heterozygous EMILIN1 mutation c.748C>T [p.R250C] located in the coiled coil forming region of the protein, in four affected members of an autosomal dominant family presenting a distal motor neuropathy phenotype. In affected patient a sensory nerve biopsy showed slight and unspecific changes in the number and morphology of myelinated fibers. Immunofluorescence study of a motor nerve within a muscle biopsy documented the presence of EMILIN-1 in nerve structures. Skin section and skin derived fibroblasts displayed a reduced extracellular deposition of EMILIN-1 protein with a disorganized network of poorly ramified fibers in comparison with controls. Downregulation of emilin1a in zebrafish displayed developmental delay, locomotion defects, and abnormal axonal arborization from spinal cord motor neurons. The phenotype was complemented by wild-type zebrafish emilin1a, and partially the human wild-type EMILIN1 cRNA, but not by the cRNA harboring the novel c.748C>T [p.R250C]. These data suggest a role of EMILIN-1 in the pathogenesis of diseases affecting the peripheral nervous system.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.nbd.2020.104757DOI Listing
April 2020

Biallelic DMXL2 mutations impair autophagy and cause Ohtahara syndrome with progressive course.

Brain 2019 12;142(12):3876-3891

Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy.

Ohtahara syndrome, early infantile epileptic encephalopathy with a suppression burst EEG pattern, is an aetiologically heterogeneous condition starting in the first weeks or months of life with intractable seizures and profound developmental disability. Using whole exome sequencing, we identified biallelic DMXL2 mutations in three sibling pairs with Ohtahara syndrome, belonging to three unrelated families. Siblings in Family 1 were compound heterozygous for the c.5135C>T (p.Ala1712Val) missense substitution and the c.4478C>G (p.Ser1493*) nonsense substitution; in Family 2 were homozygous for the c.4478C>A (p.Ser1493*) nonsense substitution and in Family 3 were homozygous for the c.7518-1G>A (p.Trp2507Argfs*4) substitution. The severe developmental and epileptic encephalopathy manifested from the first day of life and was associated with deafness, mild peripheral polyneuropathy and dysmorphic features. Early brain MRI investigations in the first months of life revealed thin corpus callosum with brain hypomyelination in all. Follow-up MRI scans in three patients revealed progressive moderate brain shrinkage with leukoencephalopathy. Five patients died within the first 9 years of life and none achieved developmental, communicative or motor skills following birth. These clinical findings are consistent with a developmental brain disorder that begins in the prenatal brain, prevents neural connections from reaching the expected stages at birth, and follows a progressive course. DMXL2 is highly expressed in the brain and at synaptic terminals, regulates v-ATPase assembly and activity and participates in intracellular signalling pathways; however, its functional role is far from complete elucidation. Expression analysis in patient-derived skin fibroblasts demonstrated absence of the DMXL2 protein, revealing a loss of function phenotype. Patients' fibroblasts also exhibited an increased LysoTracker® signal associated with decreased endolysosomal markers and degradative processes. Defective endolysosomal homeostasis was accompanied by impaired autophagy, revealed by lower LC3II signal, accumulation of polyubiquitinated proteins, and autophagy receptor p62, with morphological alterations of the autolysosomal structures on electron microscopy. Altered lysosomal homeostasis and defective autophagy were recapitulated in Dmxl2-silenced mouse hippocampal neurons, which exhibited impaired neurite elongation and synaptic loss. Impaired lysosomal function and autophagy caused by biallelic DMXL2 mutations affect neuronal development and synapse formation and result in Ohtahara syndrome with profound developmental impairment and reduced life expectancy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/brain/awz326DOI Listing
December 2019

'Amish Nemaline Myopathy' in 2 Italian siblings harbouring a novel homozygous mutation in Troponin-I gene.

Neuromuscul Disord 2019 10 6;29(10):766-770. Epub 2019 Sep 6.

Unit of Muscular and Neurodegenerative Disorders, Department of Neurosciences and Neurorehabilitation, Bambino Gesù Children's Hospital, Piazza S. Onofrio 4, 00165 Rome, Italy.

Amish Nemaline Myopathy is a severe form of nemaline myopathy associated to mutation in TNNT1 gene, firstly reported among the Old Order Amish. Here we report two Italian siblings who manifested, by the age of 7 months, progressive and severe muscle weakness and wasting, respiratory insufficiency, pectus carinatum deformity and failure to thrive. Muscle biopsy was consistent with nemaline myopathy and novel homozygous missense mutation in TNNT1 was found. Our cases expand the mutational spectrum of TNNT1, confirm the invariable peculiar clinical phenotype also outside the Amish population, and suggest that TNNT1 should be considered for molecular analysis in NM patients with chest deformities and progressive contractures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.nmd.2019.09.005DOI Listing
October 2019

Stem Cell Modeling of Neuroferritinopathy Reveals Iron as a Determinant of Senescence and Ferroptosis during Neuronal Aging.

Stem Cell Reports 2019 11 3;13(5):832-846. Epub 2019 Oct 3.

Proteomic of Iron Metabolism Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy; Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milan, Italy. Electronic address:

Neuroferritinopathy (NF) is a movement disorder caused by alterations in the L-ferritin gene that generate cytosolic free iron. NF is a unique pathophysiological model for determining the direct consequences of cell iron dysregulation. We established lines of induced pluripotent stem cells from fibroblasts from two NF patients and one isogenic control obtained by CRISPR/Cas9 technology. NF fibroblasts, neural progenitors, and neurons exhibited the presence of increased cytosolic iron, which was also detectable as: ferritin aggregates, alterations in the iron parameters, oxidative damage, and the onset of a senescence phenotype, particularly severe in the neurons. In this spontaneous senescence model, NF cells had impaired survival and died by ferroptosis. Thus, non-ferritin-bound iron is sufficient per se to cause both cell senescence and ferroptotic cell death in human fibroblasts and neurons. These results provide strong evidence supporting the primary role of iron in neuronal aging and degeneration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.stemcr.2019.09.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6893074PMC
November 2019

Novel mutation in sarcotubular myopathy.

Acta Myol 2019 03 1;38(1):8-12. Epub 2019 Mar 1.

Pediatric Neurology and Neuromuscular Disorders, Istituto G. Gaslini and University of Genoa, Italy.

Tripartite motif-containing protein 32 () is a member of the TRIM ubiquitin E3 ligases which ubiquitinates different substrates in muscle including sarcomeric proteins. Mutations in are associated with Limb-Girdle Muscular Dystrophy 2H. In a 66 old woman with disto-proximal myopathy, we identified a novel homozygous mutation of gene c.1781G > A (p. Ser594Asn) localised in the c-terminus NHL domain. Mutations of this domain have been also associated to Sarcotubular Myopathy (STM), a form of distal myopathy with peculiar features in muscle biopsy, now considered in the spectrum of LGMD2H. Muscle biopsy revealed severe abnormalities of the myofibrillar network with core like areas, lobulated fibres, whorled fibres and multiple vacuoles. Desmin and Myotilin stainings also pointed to accumulation as in Myofibrillar Myopathy. This report further confirms that STM and LGMD2H represent the same disorder and suggests to consider mutations in the genetic diagnosis of Sarcotubular Myopathy and Myofibrillar Myopathy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6598407PMC
March 2019

Severe early-onset developmental and epileptic encephalopathy (DEE) associated with novel compound heterozygous pathogenic variants in SLC25A22: Case report and literature review.

Seizure 2019 Aug 27;70:56-58. Epub 2019 Jun 27.

Unit of Child Neuropsychiatry, Epilepsy Centre, Department of Medical and Surgical Neuroscience and Rehabilitation, IRCSS Istituto Giannina Gaslini, Genoa, Italy. Electronic address:

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.seizure.2019.06.029DOI Listing
August 2019

Novel homozygous TSFM pathogenic variant associated with encephalocardiomyopathy with sensorineural hearing loss and peculiar neuroradiologic findings.

Neurogenetics 2019 08 2;20(3):165-172. Epub 2019 Jul 2.

Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Calambrone, Pisa, Italy.

TSFM is a nuclear gene encoding the elongation factor Ts (EFTs), an essential component of mitochondrial translational machinery. Impaired mitochondrial translation is responsible for neurodegenerative disorders characterized by multiple respiratory chain complex defects, multisystemic involvement, and neuroradiological features of Leigh-like syndrome. With the use of a next-generation sequencing (NGS)-based multigene panel for mitochondrial disorders, we identified the novel TSFM homozygous variant c.547G>A (p.Gly183Ser) in a 5-year-old boy with infantile early onset encephalocardiomyopathy, sensorineural hearing loss, and peculiar partially reversible neuroimaging features. Our findings expand the phenotypic spectrum of TSFM-related encephalopathy, offering new insights into the natural history of brain involvement and suggesting that TSFM should be investigated in pediatric mitochondrial disorders with distinctive neurologic and cardiac involvement.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10048-019-00582-5DOI Listing
August 2019
-->