Predominant cerebellar phenotype in spastic paraplegia 7 (SPG7).
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ABSTRACT:
SUBMITTER: Yahikozawa H
PROVIDER: S-EPMC4785587 | biostudies-other | 2015
REPOSITORIES: biostudies-other
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Project description:IntroductionHereditary spastic paraplegias (HSPs) comprise a group of neurodegenerative disorders characterized by progressive degeneration of upper motor neurons. Homozygous or compound heterozygous variants in COQ4 have been reported to cause primary CoQ10 deficiency-7 (COQ10D7), which is a mitochondrial disease.AimsWe aimed to screened COQ4 variants in a cohort of HSP patients.MethodsA total of 87 genetically unidentified HSP index patients and their available family members were recruited. Whole exome sequencing (WES) was performed in all probands. Functional studies were performed to identify the pathogenicity of those uncertain significance variants.ResultsIn this study, five different COQ4 variants were identified in three Chinese HSP pedigrees and two variants were novel, c.87dupT (p.Arg30*), c.304C>T (p.Arg102Cys). More importantly, we firstly described two early-onset pure HSP caused by COQ4 variants. Functional studies in patient-derived fibroblast lines revealed a reduction cellular CoQ10 levels and the abnormal mitochondrial structure.ConclusionsOur findings revealed that bilateral variants in the COQ4 gene caused HSP predominant phenotype, expanding the phenotypic spectrum of the COQ4-related disorders.
| S-EPMC11017416 | biostudies-literature
Project description:ObjectivesThe term hereditary spastic paraplegia comprises an ever-expanding array of neurological disorders with distinct aetiologies. Spastic paraplegia gene 39 is one of the many genetically defined types with features of other organs and neurological systems in addition to paraspasticity. We describe a large kindred with a novel clinical phenotype as, in addition to spastic paraplegia, affected subjects suffered from a prominent cerebellar oculomotor dysfunction with two hitherto undescribed mutations of PNPLA6.MethodsThree of five genetically tested family members of a large kindred were affected by spastic gait and a unique and prominent cerebellar oculomotor dysfunction. Further clinical, imaging, laboratory and videonystagmographic data were analyzed. Genetic analysis was done using next-generation sequencing.ResultsThe most salient clinical feature, in addition to paraspasticity, in three of five subjects was cerebellar oculomotor dysfunction with an upbeating nystagmus provoked by downward gaze. Genetic analysis revealed two hitherto unknown sequence variants in the PNPLA6 gene, a splice-site variant c.1635 + 3G > T and a missense variant c.3401A > T, p.(Asp1134Val). In addition to cerebellar oculomotor dysfunction, compound-heterozygous siblings presented with paraspasticity and a moderate hypogonadotropic hypogonadism in the female. A paternal uncle being homozygous for the splice-site variant of PNPLA6 presented with increased lower limb reflexes and an unstable gait. Treatment with 4-aminopyridine, a potassium channel blocker, lead to meaningful improvement of clinical symptoms.ConclusionsThe unique and prominent cerebellar ocular motor disorder in our family broadens the spectrum of clinical phenotypes associated with variations in the PNLA6 gene. The finding of paraspasticity with cerebellar oculomotor dysfunction alongside inconspicuous brainstem imaging may raise suspicion of complex HSP with PNPLA6 mutations.
| S-EPMC9618546 | biostudies-literature
Project description:BackgroundX-linked adrenoleukodystrophy (ALD) is one of the most common peroxisomal disorders characterized by abnormal accumulation of very long-chain fatty acids (VLCFA) in plasma and tissues and caused by mutations within ABCD1. Clinically, ALD present with various phenotypes, ranging from asymptomatic type to rapidly progressive childhood cerebral form. However, no remarkable abnormality in cerebral white matter usually makes it difficult to distinguish adult ALD from hereditary spastic paraplegia (HSP).MethodsWe analyzed the features of seven Chinese ALD patients who had a primary phenotype of spastic paraplegia. Sequencing was performed in the probands and their familial members. Detailed clinical, VLCFAs test, hormone test, magnetic resonance imaging, and electromyogram are presented.ResultsWe reported seven ALD patients from a Chinese cohort of 142 HSP patients. Genetic investigations revealed five known ABCD1 mutations (c.346G>C, c.521A>G, c.829G>T, c.1415_1416delAG, and c.1849C>T) and two novel mutations (c.454C>G, c.1452_1482del). Further auxiliary testing revealed that they had higher VLCFA and/or adrenal insufficiency.ConclusionsOur findings expand the mutation spectrum of ABCD1 and indicate that ALD represent a significant portion (4.9%, 7/142) of the spastic paraplegia entities. ALD should be considered in male patients with spastic paraplegia, even if there was no positive family history.
| S-EPMC6978395 | biostudies-literature
Project description:Hereditary spastic paraplegia is a group of clinically and genetically heterogeneous neurodegenerative disorders, often characterized by weakness and spasticity in the lower limbs. In our study, we describe a spastic paraplegia type 7 patient with an expanded phenotype who was diagnosed after the discovery of pathogenic variants in SPG7.
| S-EPMC5628248 | biostudies-literature
Project description:Mutations in the kinesin family member 5A (KIF5A) gene are mainly associated with autosomal dominant spastic paraplegia 10 (SPG10). The additional complicated symptoms of SPG10 commonly include a wide spectrum. However, cerebellar ataxia is only noticed in a very few patients. Herein, we described a large autosomal dominant family, in which the affected individuals presented with progressive spastic paraparesis and marked cerebellar ataxia. Exome sequencing revealed that a novel variant in the KIF5A gene might be responsible for the phenotype. The obvious cerebellar ataxia indicated that the KIF5A gene should be included in the expanding gene list for spasticity-ataxia spectrum.
| S-EPMC6243379 | biostudies-literature
Project description:BackgroundPathogenic variants in SPTAN1 have been linked to a remarkably broad phenotypical spectrum. Clinical presentations include epileptic syndromes, intellectual disability, and hereditary motor neuropathy.ObjectivesWe investigated the role of SPTAN1 variants in rare neurological disorders such as ataxia and spastic paraplegia.MethodsWe screened 10,000 NGS datasets across two international consortia and one local database, indicative of the level of international collaboration currently required to identify genes causative for rare disease. We performed in silico modeling of the identified SPTAN1 variants.ResultsWe describe 22 patients from 14 families with five novel SPTAN1 variants. Of six patients with cerebellar ataxia, four carry a de novo SPTAN1 variant and two show a sporadic inheritance. In this group, one variant (p.Lys2083del) is recurrent in four patients. Two patients have novel de novo missense mutations (p.Arg1098Cys, p.Arg1624Cys) associated with cerebellar ataxia, in one patient accompanied by intellectual disability and epilepsy. We furthermore report a recurrent missense mutation (p.Arg19Trp) in 15 patients with spastic paraplegia from seven families with a dominant inheritance pattern in four and a de novo origin in one case. One further patient carrying a de novo missense mutation (p.Gln2205Pro) has a complex spastic ataxic phenotype. Through protein modeling we show that mutated amino acids are located at crucial interlinking positions, interconnecting the three-helix bundle of a spectrin repeat.ConclusionsWe show that SPTAN1 is a relevant candidate gene for ataxia and spastic paraplegia. We suggest that for the mutations identified in this study, disruption of the interlinking of spectrin helices could be a key feature of the pathomechanism. © 2022 International Parkinson and Movement Disorder Society.
| S-EPMC9232883 | biostudies-literature
Project description: Not available
| S-EPMC5458666 | biostudies-literature
Project description:Recessive mutations in GJA12/GJC2, the gene that encodes the gap junction protein connexin47 (Cx47), cause Pelizaeus-Merzbacher-like disease (PMLD), an early onset dysmyelinating disorder of the CNS, characterized by nystagmus, psychomotor delay, progressive spasticity and cerebellar signs. Here we describe three patients from one family with a novel recessively inherited mutation, 99C>G (predicted to cause an Ile>Met amino acid substitution; I33M) that causes a milder phenotype. All three had a late-onset, slowly progressive, complicated spastic paraplegia, with normal or near-normal psychomotor development, preserved walking capability through adulthood, and no nystagmus. MRI and MR spectroscopy imaging were consistent with a hypomyelinating leukoencephalopathy. The mutant protein forms gap junction plaques at cell borders similar to wild-type (WT) Cx47 in transfected cells, but fails to form functional homotypic channels in scrape-loading and dual whole-cell patch clamp assays. I33M forms overlapping gap junction plaques and functional channels with Cx43, however, I33M/Cx43 channels open only when a large voltage difference is applied to paired cells. These channels probably do not function under physiological conditions, suggesting that Cx47/Cx43 channels between astrocytes and oligodendrocytes are disrupted, similar to the loss-of-function endoplasmic reticulum-retained Cx47 mutants that cause PMLD. Thus, GJA12/GJC2 mutations can result in a milder phenotype than previously appreciated, but whether I33M retains a function of Cx47 not directly related to forming functional gap junction channels is not known.
| S-EPMC2640216 | biostudies-literature
Project description:BackgroundHereditary Spastic Paraplegias (HSPs) and Hereditary Cerebellar Ataxias (HCAs) are progressive neurodegenerative disorders encompassing a spectrum of neurogenetic conditions with significant overlaps of clinical features. Spastic ataxias are a group of conditions that have features of both cerebellar ataxia and spasticity, and these conditions are frequently clinically challenging to distinguish. Accurate genetic diagnosis is crucial but challenging, particularly in resource-limited settings. This study aims to investigate the genetic basis of HSPs and HCAs in Pakistani families.MethodsFamilies from Khyber Pakhtunkhwa with at least two members showing HSP or HCA phenotypes, and who had not previously been analyzed genetically, were included. Families were referred for genetic analysis by local neurologists based on the proband's clinical features and signs of a potential genetic neurodegenerative disorder. Whole Exome Sequencing (WES) and Sanger sequencing were then used to identify and validate genetic variants, and to analyze variant segregation within families to determine inheritance patterns. The mean age of onset and standard deviation were calculated to assess variability among affected individuals, and the success rate was compared with literature reports using differences in proportions and Cohen's h.ResultsPathogenic variants associated with these conditions were identified in five of eight families, segregating according to autosomal recessive inheritance. These variants included previously reported SACS c.2182 C > T, p.(Arg728*), FA2H c.159_176del, p.(Arg53_Ile58del) and SPG11 c.2146 C > T, p.(Gln716*) variants, and two previously unreported variants in SACS c.2229del, p.(Phe743Leufs*8) and ZFYVE26 c.1926_1941del, p.(Tyr643Metfs*2). Additionally, FA2H and SPG11 variants were found to have recurrent occurrences, suggesting a potential founder effect within the Pakistani population. Onset age among affected individuals ranged from 1 to 14 years (M = 6.23, SD = 3.96). The diagnostic success rate was 62.5%, with moderate effect sizes compared to previous studies.ConclusionsThe findings of this study expand the genotypic and phenotypic spectrum of HSPs and HCAs in Pakistan and emphasize the importance of utilizing exome/genome sequencing for accurate diagnosis or support accurate differential diagnosis. This approach can improve genetic counseling and clinical management, addressing the challenges of diagnosing neurodegenerative disorders in resource-limited settings.
| S-EPMC11414091 | biostudies-literature
Project description:BackgroundHereditary spastic paraplegias (HSP) are neurodegenerative disorders characterized by lower limb spasticity and weakness, with or without additional symptoms. Mutations in ATP13A2, known to cause Kufor-Rakeb syndrome (KRS), have been recently implicated in HSP.MethodsWhole-exome sequencing was done in a Canada-wide HSP cohort.ResultsThree additional patients with homozygous ATP13A2 mutations were identified, representing 0.7% of all HSP families. Spastic paraplegia was the predominant feature, all patients suffered from psychiatric symptoms, and one patient had developed seizures. Of the identified mutations, c.2126G>C;(p.[Arg709Thr]) is novel, c.2158G>T;(p.[Gly720Trp]) has not been reported in ATP13A2-related diseases, and c.2473_2474insAAdelC;p.[Leu825Asnfs*32]) has been previously reported in KRS but not in HSP. Structural analysis of the mutations suggested a disruptive effect, and enrichment analysis suggested the potential involvement of specific pathways.ConclusionOur study suggests that in HSP patients with psychiatric symptoms, ATP13A2 mutations should be suspected, especially if they also have extrapyramidal symptoms.
| S-EPMC7057081 | biostudies-literature