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1.
Muscle Nerve ; 70(1): 152-156, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38687249

RESUMEN

INTRODUCTION/AIMS: The frequency and distribution of upper motor neuron (UMN) signs in primary lateral sclerosis (PLS) are unknown. We aimed to study the spectrum of UMN signs in PLS and compare it with hereditary spastic paraplegia (HSP). METHODS: We retrospectively analyzed the frequency of different UMN signs, including hyperreflexia (limbs and jaw), limb and tongue spasticity, Babinski, and Hoffman signs, in PLS patients at first observation and compared this respect to onset region and symptom duration. We also compared PLS versus HSP patients. RESULTS: We included 34 PLS and 20 HSP patients, with a median symptom duration at first visit of 3.0 (interquartile range, IQR = 4.0) and 19.0 (IQR = 22.0) years, respectively. In PLS patients, hyperreflexia of upper (UL) (88.2%) and lower (LL) (91.2%) limbs, and LL spasticity (79.4%) were the most common findings. Spasticity of LL was significantly (p = .012) more frequent in LL-spinal onset subgroup, tongue spasticity in bulbar-onset subgroup (p = .021), and Hoffman sign in UL-spinal onset subgroup (p = .024). The PLS subgroup with shorter disease duration had a higher frequency of abnormal jaw jerk reflex (p = .037). Compared with HSP, PLS patients had a higher frequency of UL hyperreflexia (88.2% vs. 42.1%, p < .001) and UL spasticity (44.1% vs. 0.0%, p < .001). Asymmetric distribution of UMN signs was present in PLS and not in HSP. DISCUSSION: In PLS, UL UMN signs are nearly always present and UMN sign distribution appears to be associated with onset region. At first observation, bulbar involvement, asymmetrical distribution of UMN signs and UL spasticity may indicate PLS versus HSP.


Asunto(s)
Paraplejía Espástica Hereditaria , Humanos , Paraplejía Espástica Hereditaria/fisiopatología , Paraplejía Espástica Hereditaria/diagnóstico , Masculino , Femenino , Persona de Mediana Edad , Adulto , Estudios Retrospectivos , Neuronas Motoras/fisiología , Anciano , Espasticidad Muscular/fisiopatología , Espasticidad Muscular/diagnóstico , Enfermedad de la Neurona Motora/fisiopatología , Enfermedad de la Neurona Motora/diagnóstico
2.
J Neuroophthalmol ; 42(1): e147-e152, 2022 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-33870938

RESUMEN

BACKGROUND: Type III 3-methylglutaconic aciduria (OPA 3) is a neuro-ophthalmologic syndrome consisting of early-onset bilateral optic atrophy. Since Costeff described the phenotype of 19 patients in 1989, several reports described approximately 50 patients, but most of them lack details about neuro-ophthalmic phenotype. Our aim was to characterize the clinical neuro-ophthalmic phenotype of this syndrome. METHODS: Nine patients underwent meticulous visual function history and medical documents' review. Results of best-corrected visual acuity (VA), color vision, visual field (VF), ocular motility, pupillary reaction, slit-lamp, and dilated fundus examinations were recorded. Optical coherence tomography (OCT) was performed whenever possible. RESULTS: The average VA was 1.4 ± 0.8 logarithm of the minimum angle of resolution. Poor vision was the presenting symptom in 5 patients. Six patients had decreased VA and variable degrees of optic atrophy. Humphrey VF testing of 7 patients revealed generalized depression in 5 and a cecocentral defect in 2. All patients demonstrated dysmetric saccades. Four patients had strabismus, 3 with exotropia, and one with esotropia. Seven patients had nystagmus. Ocular motility abnormality is possibly the result of cerebellar atrophy that was found in MRI studies of our patients. OCT of the retina was possible in 6 patients and revealed retinal nerve fiber layer (RNFL) thinning as well as average retinal thinning. Three patients, in whom ganglion cell layer-inner plexiform layer (IPL) measurement was possible, also showed diffused thinning. CONCLUSIONS: This study compiled data regarding neuro-ophthalmic manifestation of OPA 3 Type III patients. Contrary to established literature, poor vision was the presenting symptom in only 50% of our patients. This is the first report of OCT findings in 3MGA patients. The results demonstrated diffused thinning of the RNFL and ganglion cell complex-IPL with correlation to VA, which is in contrast to OPA1 patients in whom the most severe thinning is at the level of the papillomacular bundle. Average retinal thinning was identified at second and third decades of life, possibly resulting from early ganglion cell loss. These results may contribute to visual prognosis, and OCT may help monitor experimental therapies.


Asunto(s)
Corea , Errores Innatos del Metabolismo , Atrofia Óptica , Paraplejía Espástica Hereditaria , Corea/diagnóstico , Corea/fisiopatología , Humanos , Errores Innatos del Metabolismo/diagnóstico , Errores Innatos del Metabolismo/fisiopatología , Atrofia Óptica/diagnóstico , Atrofia Óptica/fisiopatología , Fenotipo , Paraplejía Espástica Hereditaria/diagnóstico , Paraplejía Espástica Hereditaria/fisiopatología , Tomografía de Coherencia Óptica/métodos , Agudeza Visual
3.
Int J Mol Sci ; 23(3)2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-35163618

RESUMEN

Hereditary spastic paraplegia (HSP) is a rare neurodegenerative disorder with the predominant clinical manifestation of spasticity in the lower extremities. HSP is categorised based on inheritance, the phenotypic characters, and the mode of molecular pathophysiology, with frequent degeneration in the axon of cervical and thoracic spinal cord's lateral region, comprising the corticospinal routes. The prevalence ranges from 0.1 to 9.6 subjects per 100,000 reported around the globe. Though modern medical interventions help recognize and manage the disorder, the symptomatic measures remain below satisfaction. The present review assimilates the available data on HSP and lists down the chromosomes involved in its pathophysiology and the mutations observed in the respective genes on the chromosomes. It also sheds light on the treatment available along with the oral/intrathecal medications, physical therapies, and surgical interventions. Finally, we have discussed the related diagnostic techniques as well as the linked pharmacogenomics studies under future perspectives.


Asunto(s)
Paraplejía Espástica Hereditaria/genética , Humanos , Mutación , Paraplejía Espástica Hereditaria/fisiopatología
4.
Hum Mol Genet ; 28(7): 1136-1152, 2019 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-30520996

RESUMEN

Mutations of the SPAST gene, which encodes the microtubule-severing protein spastin, are the most common cause of hereditary spastic paraplegia (HSP). Haploinsufficiency is the prevalent opinion as to the mechanism of the disease, but gain-of-function toxicity of the mutant proteins is another possibility. Here, we report a new transgenic mouse (termed SPASTC448Y mouse) that is not haploinsufficient but expresses human spastin bearing the HSP pathogenic C448Y mutation. Expression of the mutant spastin was documented from fetus to adult, but gait defects reminiscent of HSP (not observed in spastin knockout mice) were adult onset, as is typical of human patients. Results of histological and tracer studies on the mouse are consistent with progressive dying back of corticospinal axons, which is characteristic of the disease. The C448Y-mutated spastin alters microtubule stability in a manner that is opposite to the expectations of haploinsufficiency. Neurons cultured from the mouse display deficits in organelle transport typical of axonal degenerative diseases, and these deficits were worsened by depletion of endogenous mouse spastin. These results on the SPASTC448Y mouse are consistent with a gain-of-function mechanism underlying HSP, with spastin haploinsufficiency exacerbating the toxicity of the mutant spastin proteins. These findings reveal the need for a different therapeutic approach than indicated by haploinsufficiency alone.


Asunto(s)
Paraplejía Espástica Hereditaria/genética , Espastina/genética , Animales , Transporte Axonal/fisiología , Axones/metabolismo , Modelos Animales de Enfermedad , Mutación con Ganancia de Función/genética , Haploinsuficiencia , Haplotipos , Ratones , Ratones Transgénicos , Microtúbulos/metabolismo , Proteínas Mutantes/genética , Mutación , Neuronas/metabolismo , Paraplejía Espástica Hereditaria/fisiopatología , Espastina/fisiología
5.
J Neurogenet ; 35(2): 84-94, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33771085

RESUMEN

Hereditary spastic paraplegia (HSP) is a clinically and genetically heterogeneous neurodegenerative disorder, characterized by lower-limb spasticity and weakness. To date, more than 82 loci/genes (SPG1-SPG82) have been identified that contribute to the cause of HSP. Despite the use of next-generation sequencing-based methods, genetic-analysis has failed in the finding of causative genes in more than 50% of HSP patients, indicating a more significant heterogeneity and absence of a given phenotype-genotype correlation. Here, we performed whole-exome sequencing (WES) to identify HSP-causing genes in three unrelated-Iranian probands. Candidate variants were detected and confirmed in the probands and co-segregated in the family members. The phenotypic data gathered and compared with earlier cases with the same sub-types of disease. Three novel homozygous variants, c.978delT; p.Q327Kfs*39, c.A1208G; p.D403G and c.3811delT; p.S1271Lfs*44, in known HSP-causing genes including ENTPD1, CYP7B1, and ZFYVE26 were identified, respectively. Intra and interfamilial clinical variability were observed among affected individuals. Mutations in CYP7B1 and ZFYVE26 are relatively common causes of HSP and associated with SPG5A and SPG15, respectively. However, mutations in ENTPD1 are related to SPG64 which is an ultra-rare form of HSP. The research affirmed more complexities of phenotypic manifestations and allelic heterogeneity in HSP. Due to these complexities, it is not feasible to show a clear phenotype-genotype correlation in HSP cases. Identification of more families with mutations in HSP-causing genes may help the establishment of this correlation, further understanding of the molecular basis of the disease, and would provide an opportunity for genetic-counseling in these families.


Asunto(s)
Apirasa/genética , Proteínas Portadoras/genética , Familia 7 del Citocromo P450/genética , Paraplejía Espástica Hereditaria/genética , Esteroide Hidroxilasas/genética , Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Masculino , Mutación , Linaje , Fenotipo , Paraplejía Espástica Hereditaria/fisiopatología , Secuenciación del Exoma , Adulto Joven
6.
Phys Occup Ther Pediatr ; 41(1): 99-113, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-32942942

RESUMEN

AIMS: The aim of this two-part, prospective study was to determine therapist familiarity with HSP and examine diagnostic accuracy between individuals with HSP and those with Spastic Diplegic Cerebral Palsy (SD-CP). METHODS: Part-one surveyed physical therapists (PT) and physical therapist assistants (PTA) throughout Texas to determine familiarity with HSP and its gait deviations. Part-two examined accuracy in differential diagnosis of HSP versus SD-CP using gait analysis and the effects of an educational module on upper body gait deviations observed in individuals with HSP. RESULTS: Both PTs and PTAs indicated a high degree (≥73.2%) of unfamiliarity with HSP. While a majority of respondents (≥88.7%) indicated use of observational gait analysis in clinical practice, ≥92.5% indicated never receiving instruction on HSP or its associated gait deviations. Whole group analysis revealed diagnostic accuracy increased 21.7% post educational module. In addition, individual case diagnostic accuracy yielded significant improvement in 14 out of 20 cases. CONCLUSIONS: Physical and occupational therapists are in a unique position to assist with the identification and distinction of HSP from CP. This study demonstrated that brief instruction on common upper body gait deviations seen in individuals with HSP may improve a clinician's ability to distinguish SD-CP from HSP via gait analysis.


Asunto(s)
Parálisis Cerebral/diagnóstico , Parálisis Cerebral/fisiopatología , Competencia Clínica , Asistentes de Fisioterapeutas/educación , Fisioterapeutas/educación , Paraplejía Espástica Hereditaria/diagnóstico , Paraplejía Espástica Hereditaria/fisiopatología , Niño , Diagnóstico Diferencial , Trastornos Neurológicos de la Marcha/diagnóstico , Trastornos Neurológicos de la Marcha/fisiopatología , Humanos , Estudios Prospectivos
7.
Hum Mol Genet ; 27(14): 2517-2530, 2018 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-29726929

RESUMEN

Mechanisms by which long corticospinal axons degenerate in hereditary spastic paraplegia (HSP) are largely unknown. Here, we have generated induced pluripotent stem cells (iPSCs) from patients with two autosomal recessive forms of HSP, SPG15 and SPG48, which are caused by mutations in the ZFYVE26 and AP5Z1 genes encoding proteins in the same complex, the spastizin and AP5Z1 proteins, respectively. In patient iPSC-derived telencephalic glutamatergic and midbrain dopaminergic neurons, neurite number, length and branching are significantly reduced, recapitulating disease-specific phenotypes. We analyzed mitochondrial morphology and noted a significant reduction in both mitochondrial length and their densities within axons of these HSP neurons. Mitochondrial membrane potential was also decreased, confirming functional mitochondrial defects. Notably, mdivi-1, an inhibitor of the mitochondrial fission GTPase DRP1, rescues mitochondrial morphology defects and suppresses the impairment in neurite outgrowth and late-onset apoptosis in HSP neurons. Furthermore, knockdown of these HSP genes causes similar axonal defects, also mitigated by treatment with mdivi-1. Finally, neurite outgrowth defects in SPG15 and SPG48 cortical neurons can be rescued by knocking down DRP1 directly. Thus, abnormal mitochondrial morphology caused by an imbalance of mitochondrial fission and fusion underlies specific axonal defects and serves as a potential therapeutic target for SPG15 and SPG48.


Asunto(s)
Proteínas Adaptadoras del Transporte Vesicular/genética , Proteínas Portadoras/genética , GTP Fosfohidrolasas/genética , Proteínas Asociadas a Microtúbulos/genética , Proteínas Mitocondriales/genética , Paraplejía Espástica Hereditaria/genética , Axones/efectos de los fármacos , Axones/patología , Neuronas Dopaminérgicas/metabolismo , Neuronas Dopaminérgicas/patología , Dinaminas , Humanos , Células Madre Pluripotentes Inducidas , Potencial de la Membrana Mitocondrial/genética , Mesencéfalo/metabolismo , Mesencéfalo/patología , Mitocondrias/genética , Mitocondrias/patología , Dinámicas Mitocondriales/genética , Neuronas Motoras/metabolismo , Neuronas Motoras/patología , Mutación , Proyección Neuronal/efectos de los fármacos , Proyección Neuronal/genética , Quinazolinonas/farmacología , Paraplejía Espástica Hereditaria/tratamiento farmacológico , Paraplejía Espástica Hereditaria/fisiopatología
8.
Annu Rev Neurosci ; 35: 25-47, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22540978

RESUMEN

Human voluntary movement is controlled by the pyramidal motor system, a long CNS pathway comprising corticospinal and lower motor neurons. Hereditary spastic paraplegias (HSPs) are a large, genetically diverse group of inherited neurologic disorders characterized by a length-dependent distal axonopathy of the corticospinal tracts, resulting in lower limb spasticity and weakness. A range of studies are converging on alterations in the shaping of organelles, particularly the endoplasmic reticulum, as well as intracellular membrane trafficking and distribution as primary defects underlying the HSPs, with clear relevance for other long axonopathies affecting peripheral nerves and lower motor neurons.


Asunto(s)
Fibras Nerviosas Mielínicas/fisiología , Tractos Piramidales/fisiología , Paraplejía Espástica Hereditaria/fisiopatología , Animales , Proteínas Morfogenéticas Óseas/genética , Proteínas Morfogenéticas Óseas/fisiología , Retículo Endoplásmico/genética , Retículo Endoplásmico/fisiología , Humanos , Modelos Neurológicos , Enfermedades del Sistema Nervioso/genética , Enfermedades del Sistema Nervioso/fisiopatología , Neurogénesis/genética , Neurogénesis/fisiología , Transporte de Proteínas/genética , Transporte de Proteínas/fisiología , Tractos Piramidales/crecimiento & desarrollo , Paraplejía Espástica Hereditaria/genética
10.
BMC Neurol ; 20(1): 2, 2020 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-31900114

RESUMEN

BACKGROUND: Spastic paraplegia type 11 (SPG11) mutations are the most frequent cause of autosomal recessive hereditary spastic paraplegia (ARHSP). We are aiming to identify the causative mutations in SPG11 among families referred to our center with ARHSP in a Chinese population. METHODS: Targeted next-generation sequencing was performed on the patients to identify disease-causing mutations. Variants were analyzed according to their predicted pathogenicity and their relevance to the clinical phenotypes. The segregation in the family members was validated by Sanger sequencing. RESULTS: A total of 12 mutations in SPG11 gene from 9 index cases were identified, including 6 frameshift mutations, 3 missense mutations, 1 nonsense mutation, 1 splicing mutation, and 1 intron deletion mutation. In 6 of these patients, the mutations were homozygous, and the other 3 patients carried two compound heterozygous mutations. Six mutations were novel; 2 were classified as pathogenic, 1 were considered as likely pathogenic, and the other 3 were variants of unknown significance. Additionally, 1 missense heterozygous variant we found was also carried by amyotrophic lateral sclerosis (ALS) patient. Clinically and electrophysiologically, some of our ARHSP patients partially shared various features of autosomal-recessive juvenile amyotrophic lateral sclerosis (ARJALS), including combination of both UMN and LMN degeneration. CONCLUSIONS: The results contribute to extending of the SPG11 gene mutation spectrum and emphasizing a putative link between ARHSP and ARJALS.


Asunto(s)
Pueblo Asiatico/genética , Genes Recesivos/genética , Proteínas/genética , Paraplejía Espástica Hereditaria , Adolescente , Adulto , Niño , China , Femenino , Humanos , Masculino , Mutación/genética , Paraplejía Espástica Hereditaria/genética , Paraplejía Espástica Hereditaria/fisiopatología , Adulto Joven
11.
J Peripher Nerv Syst ; 25(2): 117-124, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32096284

RESUMEN

KIF1A-related disorders (KRD) were first described in 2011 and the phenotypic spectrum has subsequently expanded to encompass a range of central and peripheral nervous system involvement. Here we present a case series demonstrating the range of clinical, neurophysiological, and radiological features which may occur in childhood-onset KRD. We report on all the children and young people seen at a single large tertiary centre. Data were collected through a retrospective case-notes review. Twelve individuals from 10 families were identified. Eight different mutations were present, including four novel mutations. Two patients displayed a very severe phenotype including congenital contractures, severe spasticity and/or dystonia, dysautonomia, severe sensorimotor polyneuropathy and optic atrophy, significant white matter changes on brain MRI, respiratory insufficiency, and complete lack of neurodevelopmental progress. The remaining 10 patients represented a spectrum of severity with common features including a movement disorder with spasticity and/or dystonia, subtle features of dysautonomia, sensory axonal neuropathy, varying degrees of optic atrophy and of learning and/or behavioural difficulties, and subtle or absent-but sometimes progressive-changes in white matter on MRI. Epilepsy was common among the more severely affected children. This case series demonstrates that KRD comprise a range of neurological disorders, with both the milder and the more severe forms combining central and peripheral (including autonomic) nervous system deficits.


Asunto(s)
Enfermedades del Sistema Nervioso Central , Distonía , Cinesinas/genética , Enfermedades del Sistema Nervioso Periférico , Disautonomías Primarias , Paraplejía Espástica Hereditaria , Adulto , Enfermedades del Sistema Nervioso Central/diagnóstico , Enfermedades del Sistema Nervioso Central/genética , Enfermedades del Sistema Nervioso Central/patología , Enfermedades del Sistema Nervioso Central/fisiopatología , Niño , Distonía/diagnóstico , Distonía/genética , Distonía/patología , Distonía/fisiopatología , Femenino , Humanos , Lactante , Masculino , Enfermedades del Sistema Nervioso Periférico/diagnóstico , Enfermedades del Sistema Nervioso Periférico/genética , Enfermedades del Sistema Nervioso Periférico/patología , Enfermedades del Sistema Nervioso Periférico/fisiopatología , Disautonomías Primarias/diagnóstico , Disautonomías Primarias/genética , Disautonomías Primarias/patología , Disautonomías Primarias/fisiopatología , Estudios Retrospectivos , Paraplejía Espástica Hereditaria/diagnóstico , Paraplejía Espástica Hereditaria/genética , Paraplejía Espástica Hereditaria/patología , Paraplejía Espástica Hereditaria/fisiopatología , Adulto Joven
12.
Neuropediatrics ; 51(2): 146-153, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-31805580

RESUMEN

Several de novo variants in the KIF1A gene have been reported to cause a complicated form of hereditary spastic paraplegia. Additional symptoms include cognitive impairment and varying degrees of peripheral neuropathy, epilepsy, decreased visual acuity, and ataxia. We describe four patients (ages 10-18 years), focusing on their mobility and gait characteristics. Two patients were not able to walk without assistance and showed a severe abnormal gait pattern, crouch gait. At examination, severe contractures were found.In addition to describing the different phenotypes with specific attention to gait in our cases, we reviewed known KIF1A mutations and summarized their associated phenotypes.We conclude that mobility and cognition are severely affected in children with spastic paraplegia due to de novo KIF1A mutations. Deterioration in mobility is most likely due to progressive spasticity, muscle weakness, and the secondary development of severe contractures, possibly combined with an additional progressive polyneuropathy. Close follow-up and treatment of these patients are warranted.


Asunto(s)
Disfunción Cognitiva/fisiopatología , Trastornos Neurológicos de la Marcha/fisiopatología , Cinesinas/genética , Limitación de la Movilidad , Enfermedades del Sistema Nervioso Periférico/fisiopatología , Paraplejía Espástica Hereditaria/genética , Paraplejía Espástica Hereditaria/fisiopatología , Adolescente , Ataxia/etiología , Ataxia/fisiopatología , Niño , Disfunción Cognitiva/etiología , Epilepsia/etiología , Epilepsia/fisiopatología , Femenino , Trastornos Neurológicos de la Marcha/etiología , Humanos , Masculino , Enfermedades del Sistema Nervioso Periférico/etiología , Fenotipo , Paraplejía Espástica Hereditaria/complicaciones , Trastornos de la Visión/etiología , Trastornos de la Visión/fisiopatología
13.
Neurol Sci ; 41(3): 699-703, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31814071

RESUMEN

BACKGROUND: Spastic paraplegia type 8 (SPG8) is an autosomal-dominant form of hereditary spastic paraplegia (AD-HSP) caused by a mutation in the KIAA0196 gene. SPG8 accounts for 1% of less of all AD-HSP and the genotype-phenotype correlation remains poorly understood. METHODS: We report the first clinical and genetic description of SPG8 disease in Italian patients. We identified four new mutations in KIAA0196 gene. These variants were identified using a multigene targeted resequencing HSP panel. We took this opportunity to review the pertinent literature. RESULTS: Age at disease onset was in the third or fourth decade of life. Stiffness of the lower limb with spastic gait, walking impairment, and decreased vibration sense were common early symptoms. Subjects of two families had bladder control abnormalities. Unlike previous reported cases, Italian SPG8 subjects have pure form of spastic paraparesis without cranial nerve involvement, and onset is in adult life. DISCUSSION: By a clinical point of view, it is hard to differentiate SPG8 from the SPG4, in which bladder and vibration sense dysfunctions are frequent signs. The differential diagnosis with other forms of AD-HSPs seems relatively easier if one considers the early-onset manifestations in SPG3A and the peripheral nervous system and cerebellar involvement seen in SPG31.


Asunto(s)
Paraplejía/genética , Paraplejía/fisiopatología , Proteínas/genética , Paraplejía Espástica Hereditaria/genética , Paraplejía Espástica Hereditaria/fisiopatología , Adulto , Estudios de Asociación Genética , Humanos , Italia , Persona de Mediana Edad , Paraplejía/diagnóstico , Linaje , Paraplejía Espástica Hereditaria/diagnóstico
14.
J Cell Sci ; 130(20): 3507-3516, 2017 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-28860117

RESUMEN

Hereditary spastic paraplegias (HSPs) are characterized by spasticity and weakness of the lower limbs, resulting from length-dependent axonopathy of the corticospinal tracts. In humans, the HSP-related atlastin genes ATL1-ATL3 catalyze homotypic membrane fusion of endoplasmic reticulum (ER) tubules. How defects in neuronal Atlastin contribute to axonal degeneration has not been explained satisfactorily. Using Drosophila, we demonstrate that downregulation or overexpression of Atlastin in motor neurons results in decreased crawling speed and contraction frequency in larvae, while adult flies show progressive decline in climbing ability. Broad expression in the nervous system is required to rescue the atlastin-null Drosophila mutant (atl2 ) phenotype. Importantly, both spontaneous release and the reserve pool of synaptic vesicles are affected. Additionally, axonal secretory organelles are abnormally distributed, whereas presynaptic proteins diminish at terminals and accumulate in distal axons, possibly in lysosomes. Our findings suggest that trafficking defects produced by Atlastin dysfunction in motor neurons result in redistribution of presynaptic components and aberrant mobilization of synaptic vesicles, stressing the importance of ER-shaping proteins and the susceptibility of motor neurons to their mutations or depletion.


Asunto(s)
Proteínas de Drosophila/fisiología , GTP Fosfohidrolasas/fisiología , Terminales Presinápticos/fisiología , Animales , Transporte Biológico , Drosophila melanogaster , Larva/fisiología , Locomoción , Neuronas Motoras/metabolismo , Paraplejía Espástica Hereditaria/genética , Paraplejía Espástica Hereditaria/fisiopatología , Transmisión Sináptica , Vesículas Sinápticas/metabolismo
15.
J Cell Sci ; 130(2): 453-465, 2017 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-27909242

RESUMEN

The locomotor deficits in the group of diseases referred to as hereditary spastic paraplegia (HSP) reflect degeneration of upper motor neurons, but the mechanisms underlying this neurodegeneration are unknown. We established a Drosophila model for HSP, atlastin (atl), which encodes an ER fusion protein. Here, we show that neuronal atl loss causes degeneration of specific thoracic muscles that is preceded by other pathologies, including accumulation of aggregates containing polyubiquitin, increased generation of reactive oxygen species and activation of the JNK-Foxo stress response pathway. We show that inhibiting the Tor kinase, either genetically or by administering rapamycin, at least partially reversed many of these pathologies. atl loss from muscle also triggered muscle degeneration and rapamycin-sensitive locomotor deficits, as well as polyubiquitin aggregate accumulation. These results indicate that atl loss triggers muscle degeneration both cell autonomously and nonautonomously.


Asunto(s)
Drosophila melanogaster/fisiología , Sirolimus/farmacología , Paraplejía Espástica Hereditaria/patología , Animales , Modelos Animales de Enfermedad , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/efectos de los fármacos , Técnicas de Silenciamiento del Gen , Larva/efectos de los fármacos , Larva/metabolismo , Longevidad/efectos de los fármacos , Masculino , Actividad Motora/efectos de los fármacos , Actividad Motora/fisiología , Células Musculares/efectos de los fármacos , Células Musculares/metabolismo , Neuronas/metabolismo , Fenotipo , Poliubiquitina/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal/efectos de los fármacos , Sirolimus/administración & dosificación , Paraplejía Espástica Hereditaria/fisiopatología
16.
BMC Med Genet ; 20(1): 119, 2019 07 04.
Artículo en Inglés | MEDLINE | ID: mdl-31272422

RESUMEN

BACKGROUND: Mutations in ARL6IP1, which encodes a tetraspan membrane protein localized to the endoplasmic reticulum (ER), have been recently described in a large family with a complicated form of hereditary spastic paraplegia (HSP). CASE PRESENTATION: We sought to expand the HSP phenotype associated with ARL6IP1 variants by examining a Saudi kindred with a clinically more severe presentation, which resulted in spontaneous neonatal death of both affected siblings. Clinical features encompassed not only spastic paraplegia but also developmental delay, microcephaly, cerebral atrophy, periventricular leukoencephalopathy, hypotonia, seizures, spasticity, jejunal stricture, gastrointestinal reflux, neuropathy, dysmorphism and respiratory distress. We performed clinical assessment and radiological studies of this family, in addition to homozygosity mapping and whole exome sequencing (WES) to identify the disease-associated variant. Homozygosity mapping localized the causative gene to a region on chromosome 16 harboring ARL6IP1. WES of the index case identified the homoallelic nonsense variant, c.112C > T in ARL6IP1 that segregated with the phenotype and was predicted to result in loss of the protein. Allelic expression analysis of the parents demonstrated downward pressure on the mutant allele, suggestive of nonsense-mediated decay. CONCLUSIONS: Our report shows that the phenotype associated with ARL6IP1 variants may be broader and more acute than so far reported and identifies fatal HSP as the severe end of the phenotypic spectrum of ARL6IP1 variants.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/genética , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad/genética , Variación Genética , Proteínas de la Membrana/genética , Mutación , Paraplejía Espástica Hereditaria/genética , Alelos , Preescolar , Retículo Endoplásmico/metabolismo , Femenino , Regulación de la Expresión Génica , Homocigoto , Humanos , Masculino , Mutación/genética , Linaje , Fenotipo , Arabia Saudita , Paraplejía Espástica Hereditaria/diagnóstico por imagen , Paraplejía Espástica Hereditaria/fisiopatología , Secuenciación del Exoma
17.
J Hum Genet ; 64(11): 1055-1065, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31515522

RESUMEN

We aimed to find a new causative gene and elucidate the molecular mechanisms underlying a new type of hereditary spastic paraplegia (HSP). Patients with HSP were recruited from the Japan Spastic Paraplegia Research Consortium (JASPAC). Exome sequencing of genomic DNA from patients in four families was carried out, followed by Sanger sequencing of the UBAP1 gene. A mouse homolog of one UBAP1 frameshift mutation carried by one of the patients was created as a disease model. Functional properties of the UBAP1 wild type and UBAP1-mutant in mouse hippocampus neurons were examined. We identified three novel heterozygous loss of function mutations (c.425_426delAG, c.312delC, and c.535G>T) in the UBAP1 gene as the genetic cause of a new type of HSP (SPG80). All the patients presented identical clinical features of a pure type of juvenile-onset HSP. Functional studies on mouse hippocampal neurons revealed that the C-terminal deletion UBAP1-mutant of our disease model had lost its ability to bind ubiquitin in vitro. Overexpression of the UBAP1 wild type interacts directly with ubiquitin on enlarged endosomes, while the UBAP1-mutant cannot be recruited to endosome membranes. Our study demonstrated that mutations in the UBAP1 gene cause a new type of HSP and elucidated its pathogenesis. The full-length UBAP1 protein is involved in endosomal dynamics in neurons, while loss of UBAP1 function may perturb endosomal fusion and sorting of ubiquitinated cargos. These effects could be more prominent in neurons, thereby giving rise to the phenotype of a neurodegenerative disease such as HSP.


Asunto(s)
Proteínas Portadoras/genética , Predisposición Genética a la Enfermedad , Enfermedades Neurodegenerativas/genética , Paraplejía Espástica Hereditaria/genética , Adolescente , Adulto , Edad de Inicio , Anciano , Anciano de 80 o más Años , Animales , Pueblo Asiatico , Niño , Modelos Animales de Enfermedad , Endosomas/genética , Femenino , Mutación del Sistema de Lectura/genética , Humanos , Japón , Masculino , Ratones , Persona de Mediana Edad , Enfermedades Neurodegenerativas/fisiopatología , Neuronas/metabolismo , Neuronas/patología , Linaje , Fenotipo , Paraplejía Espástica Hereditaria/fisiopatología , Secuenciación del Exoma
18.
Am J Med Genet A ; 179(7): 1122-1125, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31087769

RESUMEN

Variants in FA2H have been associated with a wide range of phenotypes including hereditary spastic paraplegia type 35 (SPG35); however, genetically confirmed cases have not been reported in Africa. We report here the first African family with a variant in the FA2H gene causing SPG35. Four affected siblings with consanguineous parents presented with walking difficulty at age 2-3 and progressive limb weakness. They became wheelchair-bound 2 years after disease onset. Neurological examination confirmed lower greater than upper limb weakness and atrophy, brisk reflexes throughout, and spasticity with scissor legs. The patients also had choking, urinary urgency, and mental retardation. A brain MRI showed thin corpus callosum and periventricular leucodystrophy. Testing of 58 SPG genes showed a homozygous variant in FA2H at the exon 5 donor site c.786+1G>A, which has previously been shown to cause skipping of exons 5 and 6 of the gene transcript. This variant segregated with the disease in the family. This variant has been reported previously with a similar phenotype and slow progression in a population with different background. Here, we confirm its pathogenicity and expand its genetic epidemiology. Studying diverse populations may help to increase understanding of the disease mechanism and ultimately lead to therapeutic targets.


Asunto(s)
Discapacidad Intelectual/genética , Oxigenasas de Función Mixta/genética , Mutación , Paraplejía Espástica Hereditaria/genética , Adolescente , Adulto , Obstrucción de las Vías Aéreas/fisiopatología , Niño , Consanguinidad , Cuerpo Calloso/diagnóstico por imagen , Cuerpo Calloso/metabolismo , Cuerpo Calloso/patología , Exones , Femenino , Homocigoto , Humanos , Discapacidad Intelectual/diagnóstico por imagen , Discapacidad Intelectual/fisiopatología , Imagen por Resonancia Magnética , Masculino , Malí , Linaje , Fenotipo , Hermanos , Paraplejía Espástica Hereditaria/diagnóstico por imagen , Paraplejía Espástica Hereditaria/fisiopatología
19.
Eur J Neurol ; 26(4): 687-693, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30489674

RESUMEN

BACKGROUND AND PURPOSE: SPAST mutations are the most common cause of hereditary spastic paraplegia (SPG4-HSP), which is characterized by progressive lower limb weakness, spasticity and hyperreflexia. There are few studies about non-motor manifestations in this disease and none about autonomic involvement. Therefore, the aim was to determine the frequency and pattern of autonomic complaints in patients with SPG4-HSP, as well as to determine the clinical relevance and the possible factors associated with these manifestations. METHODS: Thirty-four molecularly confirmed SPG4 patients were recruited in a multicenter cross-sectional study, of whom 26 underwent detailed neurophysiological testing (heart rate variability, sympathetic skin response and the Quantitative Sudomotor Axonal Reflex Test). The Scales for Outcomes in Parkinson's Disease - Autonomic Questionnaire (SCOPA-AUT) was applied to quantify the severity of autonomic symptoms. Results were compared with 44 age- and gender-matched healthy controls using non-parametric tests. P values <0.05 were considered significant. RESULTS: In the SPG4-HSP group, there were 18 men with a mean age of 47.7 ± 12.6 years. SCOPA-AUT scores were similar between patients and controls (P = 0.238). Only the urinary domain subscore was significantly higher amongst patients (4 vs. 2.5, P = 0.05). Absent sympathetic skin response in the hands and feet was more frequent amongst patients (20% vs. 0%, P < 0.001, and 64% vs. 0%, P = 0.006, respectively). Quantitative Sudomotor Axonal Reflex Test responses were also smaller throughout all recording regions in the SPG4-HSP group. CONCLUSION: Our results indicate that SPG4-HSP patients have sudomotor dysfunction caused by damaged small post-ganglionic cholinergic fibers. Damage in SPG4-HSP extends to the peripheral nervous system.


Asunto(s)
Sistema Nervioso Autónomo/fisiopatología , Mutación , Paraplejía/fisiopatología , Paraplejía Espástica Hereditaria/fisiopatología , Espastina/genética , Adenosina Trifosfatasas/genética , Adulto , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Paraplejía/genética , Paraplejía Espástica Hereditaria/genética
20.
Neurourol Urodyn ; 38(4): 1081-1085, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30848841

RESUMEN

AIMS: Purposes of this study were to describe lower urinary tract symptoms (LUTS) and related urodynamic patterns in patients with hereditary spastic paraplegia (HSP), and to characterize LUTS management and associated uronephrological complications. METHODS: We retrospectively reviewed medical files of HSP patients, consecutively followed in our Physical and Rehabilitation Medicine Department between 1999 and 2016. Clinical, urodynamic, and radiological data were collected and analyzed. Different treatments which have been prescribed and uronephrological complications were also recorded. Patients with other neurological or urological diseases were excluded. RESULTS: Thirty-three patients with HSP were included. Mean duration of follow-up was 8.1 ± 5 years, mean age 62 ± 14 years, and 70% were men. The most frequent LUTS was urgency and voiding dysfunction (both 69.7%). Incontinence and retention with a significant postvoid residue above 100 mL accounted for 66.7% and 57.6% of initial symptoms respectively. Neurogenic detrusor overactivity was diagnosed in 80.7% of patients. Two-thirds of our cohort were treated with anticholinergics and 9.1% required intradetrusor botulinum-toxin injections. Only 27.3% of patients performed clean intermittent self-catheterization. Febrile urinary tract infections (21.2%), urolithiasis (15,1%), hydronephrosis (6%), and chronic renal failure (9.1%) were found. CONCLUSION: Given their high prevalence and the risk of uronephrological complications, LUTS should be systematically assessed in HSP patients. The systematic screening of urological dysfunction in this population would improve its management, decrease the incidence of uronephrological complications, and increase the quality of life.


Asunto(s)
Síntomas del Sistema Urinario Inferior/etiología , Calidad de Vida , Paraplejía Espástica Hereditaria/complicaciones , Urodinámica/fisiología , Anciano , Manejo de la Enfermedad , Femenino , Humanos , Cateterismo Uretral Intermitente , Síntomas del Sistema Urinario Inferior/fisiopatología , Síntomas del Sistema Urinario Inferior/terapia , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Paraplejía Espástica Hereditaria/fisiopatología
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