rs752623413
Variant summary
Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM2PP3_ModeratePP5_Very_Strong
The NM_003119.4(SPG7):c.2228T>C(p.Ile743Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000632 in 1,613,982 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).
Frequency
Consequence
NM_003119.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 12 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
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SPG7 | NM_003119.4 | c.2228T>C | p.Ile743Thr | missense_variant | Exon 17 of 17 | ENST00000645818.2 | NP_003110.1 | |
SPG7 | XM_047434540.1 | c.914T>C | p.Ile305Thr | missense_variant | Exon 9 of 9 | XP_047290496.1 | ||
SPG7 | NM_001363850.1 | c.*6T>C | 3_prime_UTR_variant | Exon 18 of 18 | NP_001350779.1 | |||
SPG7 | XM_047434537.1 | c.*6T>C | 3_prime_UTR_variant | Exon 13 of 13 | XP_047290493.1 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000526 AC: 8AN: 152186Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000517 AC: 13AN: 251340Hom.: 0 AF XY: 0.0000589 AC XY: 8AN XY: 135900
GnomAD4 exome AF: 0.0000643 AC: 94AN: 1461796Hom.: 0 Cov.: 31 AF XY: 0.0000646 AC XY: 47AN XY: 727196
GnomAD4 genome AF: 0.0000526 AC: 8AN: 152186Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74352
ClinVar
Submissions by phenotype
Hereditary spastic paraplegia 7 Pathogenic:13Other:1
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This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 743 of the SPG7 protein (p.Ile743Thr). This variant is present in population databases (rs752623413, gnomAD 0.01%). This missense change has been observed in individuals with autosomal recessive primary lateral sclerosis and hereditary spastic paraplegia and adult-onset upper motor neuron syndrome, ataxia, or progressive external ophthalmoplegia (PMID: 18799786, 22964162, 24727571, 25681447, 27123479). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 215218). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt SPG7 protein function with a positive predictive value of 80%. For these reasons, this variant has been classified as Pathogenic. -
Variant summary: SPG7 c.2228T>C (p.Ile743Thr) results in a non-conservative amino acid change located in the Peptidase M41 domain (IPR000642) of the encoded protein sequence. Four of four in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 5.2e-05 in 251340 control chromosomes (gnomAD). c.2228T>C has been reported in the literature in multiple individuals affected with Ataxia/Hereditary Spastic Paraplegia 7 (e.g. van Gassen_2012, Coutelier_2018, Mancini_2019, Bogdanova-Mihaylova_2021). These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Seven ClinVar submitters (evaluation after 2014) cite the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
A Heterozygous Missense variant c.2228T>C in Exon 17 of the SPG7 gene that results in the amino acid substitution p.Ile743Thr was identified. The observed variant has a minor allele frequency of 0.00005/0.00003% in gnomAD exomes and genomes, respectively. The severity of the impact of this variant on the protein is medium, based on the effect of the protein and REVEL score . Rare Exome Variant Ensemble Learner (REVEL) is an ensembl method for predicting the pathogenicity of missense variants based on a combination of scores from 13 individual tools: MutPred, FATHMM v2.3, VEST 3.0, PolyPhen-2, SIFT, PROVEAN, MutationAssessor, MutationTaster, LRT, GERP++, SiPhy, phyloP, and phastCons. The REVEL score for an individual missense variant can range from 0 to 1, with higher scores reflecting greater likelihood that the variant is disease-causing. ClinVar has also classified this variant as PathogenicLikelyPathogenic(Variant ID 215218). This variant has been previously reported in Pfeffer et al., 2015. Based on the above evidence this variant has been classified as Likely Pathogenic according to the ACMG guidelines. -
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GenomeConnect assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. GenomeConnect staff make no attempt to reinterpret the clinical significance of the variant. -
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The observed missense variant c.2228T>Cp.Ile743Thr in SPG7 gene has been reported in homozygous/compound heterozygous state in multiple individuals affected with Ataxia/Hereditary Spastic Paraplegia 7 Bogdanova-Mihaylova et al., 2021, Mancini et al., 2019. The p.Ile743Thr variant is reported with 0.005% allele freqeuncy in gnomAD Exomes. It has been submitted to ClinVar as Likely Pathogenic/ Pathogenic multiple submissions. Multiple lines of computational evidence Polyphen-probably damaging, SIFT-damaging and Mutation Taster-disease causing predict a damaging effect on protein structure and function for this variant. The amino acid Ile at position 743 is changed to a Thr changing protein sequence and it might alter its composition and physico-chemical properties. The reference amino acid p.Ile743Thr in SPG7 is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. However, experimental studies on the pathogenicity of the variant are not available. For these reasons, this variant has been classified as Pathogenic. -
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Spastic ataxia Pathogenic:2
Missense variant of SPG7 predicted that is predicted to disrupt the function of the mitochondrial metalloprotease. The allele frequency is low (gnomAD AF = 4.95e-5) but the variant has previously been reported multiple times (13) through ClinVar for Hereditary Spastic Paraplegia 7, and spastic ataxia. In silico predictions support loss-of-function of the allele (CADD = 25.4; SIFT = 0.99). The metalloprotease is important for mitochondrial function, which correlates with the mitochondrial-related phenotypes of associated condition. Causes Spastic ataxia with episodic manifestations in compound heterozygosity with NM_003119.4 c.1861C>T. -
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not provided Pathogenic:2
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In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 32816195, 34758253, 25681447, 22964162, 18799786, 29023604, 27790088, 29482223, 28362824, 30098094, 24727571, 33300680, 35869996, 34983064, 34445196, 35872528, 27123479) -
SPG7-related disorder Pathogenic:1
The SPG7 c.2228T>C variant is predicted to result in the amino acid substitution p.Ile743Thr. This variant has been reported in the compound heterozygous state in multiple individuals with spastic paraplegia, upper motor disease, or ataxia (Brugman et al. 2008. PubMed ID: 18799786; Pfeffer et al. 2015. PubMed ID: 25681447; Coutelier et al. 2018. PubMed ID: 29482223). This variant is reported in 0.0096% of alleles in individuals of Ashkenazi Jewish descent in gnomAD (http://gnomad.broadinstitute.org/variant/16-89623341-T-C). This variant has been classified as pathogenic or likely pathogenic by multiple independent submitters to the ClinVar database (https://www.ncbi.nlm.nih.gov/clinvar/variation/215218/). Given the evidence, we interpret c.2228T>C (p.Ile743Thr) as pathogenic for autosomal recessive disease. -
Hereditary spastic paraplegia Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at