Pathogenic Variant of REEP1 in a Korean Family with Autosomal-Dominant Hereditary Spastic Paraplegia.
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ABSTRACT:
SUBMITTER: Park HJ
PROVIDER: S-EPMC5897212 | biostudies-literature | 2018 Apr
REPOSITORIES: biostudies-literature
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Pathogenic Variant of REEP1 in a Korean Family with Autosomal-Dominant Hereditary Spastic Paraplegia.
Park Hyung Jun HJ Lee Myung Jun MJ Lee Jee Eun JE Park Kee Duk KD Choi Young Chul YC
Journal of clinical neurology (Seoul, Korea) 20180401 2
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Project description:BackgroundMutations in the SPG4 gene (spastin) and in the SPG3A gene (atlastin) account for the majority of 'pure' autosomal dominant form of hereditary spastic paraplegia (HSP). Recently, mutations in the REEP1 gene were identified to cause autosomal dominant HSP type SPG31. The purpose of this study was to determine the prevalence of REEP1 mutations in a cohort of 162 unrelated Caucasian index patients with 'pure' HSP and a positive family history (at least two persons per family presented symptoms).Methods162 patients were screened for mutations by, both, DHPLC and direct sequencing.ResultsTen mutations were identified in the REEP1 gene, these included eight novel mutations comprising small insertions/deletions causing frame shifts and subsequently premature stop codons, one nonsense mutation and one splice site mutation as well as two missense mutations. Both missense mutations and the splice site mutation were not identified in 170 control subjects.ConclusionIn our HSP cohort we found pathogenic mutations in 4.3% of cases with autosomal dominant inheritance. Our results confirm the previously observed mutation range of 3% to 6.5%, respectively, and they widen the spectrum of REEP1 mutations.
| S-EPMC2492855 | biostudies-literature
Project description:Autosomal recessive KIF1A missense mutations cause hereditary spastic paraplegia (HSP) type SPG30, while recessive truncations lead to sensory and autonomic neuropathy (HSN2C) and many de novo missense mutations are associated with cognitive impairment. Here, we describe family members across three generations with pure HSP. A heterozygous p.Ser69Leu KIF1A mutation segregates with those afflicted. The same variant was previously reported in a Finnish father and son with pure HSP as well as four members of a Sicilian kindred with more intrafamilial phenotypic variability. This further validates the pathogenicity of the p.Ser69Leu mutation and suggests that it may represent a mutation hot spot.
| S-EPMC5682118 | biostudies-literature
Project description:Background and purposeHereditary spastic paraplegia (HSP) is a genetically heterogeneous group of neurodegenerative disorders that are characterized by progressive spasticity and weakness of the lower limbs. Mutations in the spastin gene (SPAST) are the most common causes of HSP, accounting for 40-67% of autosomal dominant HSP (AD-HSP) and 12-18% of sporadic cases. Mutations in the atlastin-1 gene (ATL1) and receptor expression-enhancing protein 1 gene (REEP1) are the second and third most common causes of AD-HSP, respectively.MethodsDirect sequence analysis was used to screen mutations in SPAST, ATL1, and REEP1 in 27 unrelated Korean patients with pure and complicated HSP. Multiplex ligation-dependent probe amplification was also performed to detect copy-number variations of the three genes.ResultsTen different SPAST mutations were identified in 11 probands, of which the following 6 were novel: c.760A>T, c.131C>A, c.1351_1353delAGA, c.376_377dupTA, c.1114A>G, and c.1372A>C. Most patients with SPAST mutations had AD-HSP (10/11, 91%), and the frequency of SPAST mutations accounted for 66.7% (10/15) of the AD-HSP patients. No significant correlation was found between the presence of the SPAST mutation and any of the various clinical parameters of pure HSP. No ATL1 and REEP1 mutations were detected.ConclusionsWe conclude that SPAST mutations are responsible for most Korean cases of genetically confirmed AD-HSP. Our observation of the absence of ATL1 and REEP1 mutations needs to be confirmed in larger series.
| S-EPMC4101104 | biostudies-literature
Project description:The hereditary spastic paraplegias (HSPs) are genetically heterogeneous disorders characterized by progressive lower-extremity weakness and spasticity. The molecular pathogenesis is poorly understood. We report discovery of a dominant negative mutation in the NIPA1 gene in a kindred with autosomal dominant HSP (ADHSP), linked to chromosome 15q11-q13 (SPG6 locus); and precisely the same mutation in an unrelated kindred with ADHSP that was too small for meaningful linkage analysis. NIPA1 is highly expressed in neuronal tissues and encodes a putative membrane transporter or receptor. Identification of the NIPA1 function and ligand will aid an understanding of axonal neurodegeneration in HSP and may have important therapeutic implications.
| S-EPMC1180617 | biostudies-literature
Project description:Hereditary spastic paraplegia (HSP) is a clinically and genetically heterogeneous group of disorders characterized by insidiously progressive spastic weakness in the legs. Genetic loci for autosomal dominant HSP exist on chromosomes 2p, 14q, and 15q. These loci are excluded in 45% of autosomal dominant HSP kindreds, indicating the presence of additional loci for autosomal dominant HSP. We analyzed a Caucasian kindred with autosomal dominant HSP and identified tight linkage between the disorder and microsatellite markers on chromosome 8q (maximum two-point LOD score 5.51 at recombination fraction 0). Our results clearly establish the existence of a locus for autosomal dominant HSP on chromosome 8q23-24. Currently this locus spans 6.2 cM between D8S1804 and D8S1774 and includes several potential candidate genes. Identifying this novel HSP locus on chromosome 8q23-24 will facilitate discovery of this HSP gene, improve genetic counseling for families with linkage to this locus, and extend our ability to correlate clinical features with different HSP loci.
| S-EPMC1377766 | biostudies-other
Project description:Variants in the KIF1A gene can cause autosomal recessive spastic paraplegia 30, autosomal recessive hereditary sensory neuropathy, or autosomal (de novo) dominant mental retardation type 9. More recently, variants in KIF1A have also been described in a few cases with autosomal dominant spastic paraplegia. Here, we describe 20 KIF1A variants in 24 patients from a clinical exome sequencing cohort of 347 individuals with a mostly 'pure' spastic paraplegia. In these patients, spastic paraplegia was slowly progressive and mostly pure, but with a highly variable disease onset (0-57 years). Segregation analyses showed a de novo occurrence in seven cases, and a dominant inheritance pattern in 11 families. The motor domain of KIF1A is a hotspot for disease causing variants in autosomal dominant spastic paraplegia, similar to mental retardation type 9 and recessive spastic paraplegia type 30. However, unlike these allelic disorders, dominant spastic paraplegia was also caused by loss-of-function variants outside this domain in six families. Finally, three missense variants were outside the motor domain and need further characterization. In conclusion, KIF1A variants are a frequent cause of autosomal dominant spastic paraplegia in our cohort (6-7%). The identification of KIF1A loss-of-function variants suggests haploinsufficiency as a possible mechanism in autosomal dominant spastic paraplegia.
| S-EPMC6906463 | biostudies-literature
Project description:Genetic loci for autosomal dominant pure hereditary spastic paraplegia (ADPHSP) have been mapped to chromosomes 2p, 8q, 12q, 14q, and 15q. We undertook a genomewide linkage screen of a large family with ADPHSP, for which linkage at all previously identified ADPHSP loci was excluded. Analysis of markers on chromosome 19q gave a peak pairwise LOD score of 3.72 at D19S420, allowing assignment of a novel ADPHSP locus (which we have termed "SPG12") to this region. Haplotype construction and analysis of recombination events narrowed the SPG12 locus to a 16.1-cM region between markers D19S868 and D19S902.
| S-EPMC1288126 | biostudies-literature
Project description:ObjectiveTFG mutations have previously been implicated in autosomal recessive hereditary spastic paraplegia (HSP), also known as SPG57. This study aimed to investigate the clinical and molecular features of TFG mutations in a Taiwanese HSP cohort.MethodsGenetic analysis of TFG was conducted in 242 unrelated Taiwanese HSP patients using a targeted resequencing panel covering the entire coding regions of TFG. Functional assays were performed using an in vitro cell model to assess the impact of TFG variants on protein function. Additionally, other representative TFG mutant proteins were examined to understand the broader implications of TFG mutations in HSP.ResultsThe study identified a novel homozygous TFG c.177A>C (p.(Lys59Asn)) variant in a family with adolescent-onset, pure form HSP. Functional analysis revealed that the Lys59Asn TFG variant, similar to other HSP-associated TFG mutants, exhibited a low affinity between TFG monomers and abnormal assembly of TFG homo-oligomers. These structural alterations led to aberrant intracellular distribution, compromising TFG's protein secretion function and resulting in decreased cellular viability.InterpretationThese findings confirm that the homozygous TFG c.177A>C (p.(Lys59Asn)) variant is a novel cause of SPG57. The study expands our understanding of the clinical and mutational spectrum of TFG-associated diseases, highlighting the functional defects associated with this specific TFG variant. Overall, this research contributes to the broader comprehension of the genetic and molecular mechanisms underlying HSP.
| S-EPMC11251477 | biostudies-literature
Project description:Mutations in the receptor expression enhancing protein 1 (REEP1) have recently been reported to cause autosomal dominant hereditary spastic paraplegia (HSP) type SPG31. In a large collaborative effort, we screened a sample of 535 unrelated HSP patients for REEP1 mutations and copy number variations. We identified 13 novel and 2 known REEP1 mutations in 16 familial and sporadic patients by direct sequencing analysis. Twelve out of 16 mutations were small insertions, deletions or splice site mutations. These changes would result in shifts of the open-reading-frame followed by premature termination of translation and haploinsufficiency. Interestingly, we identified two disease associated variations in the 3'-UTR of REEP1 that fell into highly conserved micro RNA binding sites. Copy number variation analysis in a subset of 133 HSP index patients revealed a large duplication of REEP1 that involved exons 2-7 in an Irish family. Clinically most SPG31 patients present with a pure spastic paraplegia; rare complicating features were restricted to symptoms or signs of peripheral nerve involvement. Interestingly, the distribution of age at onset suggested a bimodal pattern with the appearance of initial symptoms of disease either before the age of 20 years or after the age of 30 years. The overall mutation rate in our clinically heterogeneous sample was 3.0%; however, in the sub-sample of pure HSP REEP1 mutations accounted for 8.2% of all patients. These results firmly establish REEP1 as a relatively frequent autosomal dominant HSP gene for which genetic testing is warranted. We also establish haploinsufficiency as the main molecular genetic mechanism in SPG31, which should initiate and guide functional studies on REEP1 with a focus on loss-of-function mechanisms. Our results should be valid as a reference for mutation frequency, spectrum of REEP1 mutations, and clinical phenotypes associated with SPG31.
| S-EPMC2841798 | biostudies-literature
Project description:Hereditary spastic paraplegia (HSP) comprises a group of clinically and genetically heterogeneous diseases that affect the upper motor neurons and their axonal projections. For the novel SPG31 locus on chromosome 2p12, we identified six different mutations in the receptor expression-enhancing protein 1 gene (REEP1). REEP1 mutations occurred in 6.5% of the patients with HSP in our sample, making it the third-most common HSP gene. We show that REEP1 is widely expressed and localizes to mitochondria, which underlines the importance of mitochondrial function in neurodegenerative disease.
| S-EPMC1559498 | biostudies-literature