9-36217448-C-T
Variant summary
Our verdict is Likely pathogenic. Variant got 7 ACMG points: 9P and 2B. PP2PP5_Very_StrongBP4BS1_Supporting
The NM_005476.7(GNE):c.2086G>A(p.Val696Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000745 in 1,614,208 control chromosomes in the GnomAD database, including 12 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).
Frequency
Consequence
NM_005476.7 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_pathogenic. Variant got 7 ACMG points.
Transcripts
RefSeq
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
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GNE | ENST00000396594.8 | c.2179G>A | p.Val727Met | missense_variant | Exon 12 of 12 | 1 | NM_001128227.3 | ENSP00000379839.3 | ||
GNE | ENST00000642385.2 | c.2086G>A | p.Val696Met | missense_variant | Exon 12 of 12 | NM_005476.7 | ENSP00000494141.2 |
Frequencies
GnomAD3 genomes AF: 0.000453 AC: 69AN: 152208Hom.: 1 Cov.: 32
GnomAD3 exomes AF: 0.00167 AC: 419AN: 251452Hom.: 2 AF XY: 0.00226 AC XY: 307AN XY: 135898
GnomAD4 exome AF: 0.000775 AC: 1133AN: 1461882Hom.: 11 Cov.: 31 AF XY: 0.00113 AC XY: 822AN XY: 727242
GnomAD4 genome AF: 0.000460 AC: 70AN: 152326Hom.: 1 Cov.: 32 AF XY: 0.000671 AC XY: 50AN XY: 74490
ClinVar
Submissions by phenotype
GNE myopathy Pathogenic:13Uncertain:1Other:1
The observed variant c.2179G>A (p.V727M) is a known pathogenic variant found very commonly in Indian patients related to GNE Myopathy, has been observed in compound heterozygous status with the other observed variant c.97G>T (p.E33X), which has not been reported in 1000 Genomes and ExAC databases but its in-silico prediction was found to be pathogenic by PolyPhen-2, MutationTaster2 and SIFT. -
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The missense c.2086G>Ap.Val696Met variant in GNE gene has been reported previously in compound heterozygous state in multiple individuals affected with GNE myopathy Garland J, et al., 2017; Khadilkar SV, et al., 2017; Zhu W, et al., 2017. This variant has been observed to segregate with disease in related individuals Boyden SE, et al., 2011. The variant has been reported as a founder mutation in South-East Asian populations, and it is one of the most frequent alleles in Indian patients Bhattacharya S, et al., 2018. The p.Val696Met variant has been reported with allele frequency of 0.2% in gnomAD Exomes. This variant has been reported to the ClinVar database as Likely Benign / Uncertain Significance / Likely Pathogenic / Pathogenic multiple submissions. The amino acid Val at position 696 is changed to a Met changing protein sequence and it might alter its composition and physico-chemical properties. Multiple lines of computational evidences Polyphen - Probabaly damaging, SIFT - Damaging and MutationTaster - Disease causing predict a damaging effect on protein structure and function for this variant. The reference amino acid change at this position on the GNE gene is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. For these reasons, this variant has been classified as Pathogenic. -
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A Heterozygous Missense variant c.2086G>A in Exon 12 of the GNE gene that results in the amino acid substitution p.Val696Met was identified. The observed variant has a maximum allele frequency of 0.00167/0.00010% 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 Pathogenic (variant ID: 430940). This variant was reported among patients for myopathies in the Indian Subcontinent (Chakravorty S et al., 2020). Based on the above evidence this variant has been classified as Pathogenic according to the ACMG guidelines. -
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Variant summary: GNE c.2179G>A (p.Val727Met) results in a conservative amino acid change located in the N-acetylmannosamine kinase domain (UniProt) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.0017 in 251452 control chromosomes, predominantly at a frequency of 0.013 within the South Asian subpopulation in the gnomAD database, including 2 homozygotes. The observed variant frequency within South Asian control individuals in the gnomAD database is approximately 10-fold of the estimated maximal expected allele frequency for a pathogenic variant in GNE causing Inclusion Body Myopathy 2 phenotype (0.0011), suggesting that the variant is a benign polymorphism found primarily in populations of South Asian origin. However, the variant, c.2179G>A, has also been reported in the literature in numerous compound heterozygous individuals affected with Inclusion Body Myopathy 2 (IBM2) (e.g. Eisenberg_2003, Voermans_2010, Boyden_2011, Cerino_2015, Zhu_2017, Garland_2017, Bhattacharya_2018, Chakravorty_2020), and in some of these reports the variant was noted to segregate with the diseases in the affected families (Boyden_2011, Zhu_2017, Garland_2017). The variant has been reported as a founder mutation in South-East Asian populations, and it is one of the most frequent alleles in Indian patients (see e.g. Bhattacharya_2018, Chakravorty_2020). The variant was also reported in a few homozygous patients (Cerino_2015, Bhattacharya_2018, Chakravorty_2020). However, in at least one of these cases the variant was present on both chromosomes in combination with another variant, thus making this case compound heterozygous; authors of this study concluded that the near absence of homozygous p.Val727Met patients probably suggests that disease may not develop in such individuals (Bhattacharya_2018). A recent genotype-phenotype correlation study concluded that patients carrying the variant, p.Val727Met, appear to have a milder phenotype with later onset (Pogoryelova_2018). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 29480215, 21708040, 27858732, 33250842, 12497639, 28717665, 27535533, 30842975, 20175955, 27829678, Attri_2021). ClinVar contains an entry for this variant (Variation ID: 6028). Based on the evidence outlined above, this variant likely represents a hypomorphic allele, which in compound heterozygous state, together with another more severe variant in trans, can cause IBM2 and related phenotypes, however in homozygous form it might not (always) result in disease; therefore, the variant was classified as likely pathogenic. -
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NM_001128227.2:c.2179G>A in the GNE gene has an allele frequency of 0.013 in South Asian subpopulation in the gnomAD database. This variant has been reported in the compound heterozygous state with p.R160X in a patient with GNE myopathy (PMID: 25182749), and in another four cases in the compound heterozygous state with c. 910G>A, c. 1258C>T, c. 1539G>A, and c. 1703G>T(PMID: 24005727). This variant has been reported to segregate with GNE myopathy in affected families (PMID: 21708040; 28717665; 27829678). Taken together, we interprete this variant as Pathogenic/Likely pathogenic variant. ACMG/AMP Criteria applied: PM3_Strong; PP1_Moderate; PP4. -
Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with Nonaka myopathy (MIM#605820) and Sialuria (MIM#269921). (I) 0108 - This gene is associated with both recessive and dominant disease. Variants associated with Sialuria (MIM#2699210) are located at codons Arg263 and Arg266 (PMID: 23842869). (I) 0200 - Variant is predicted to result in a missense amino acid change from alanine to valine. (I) 0251 - This variant is heterozygous. (I) 0305 - Variant is present in gnomAD (v2) >=0.01 and <0.03 for a recessive condition (418 heterozygotes, 2 homozygotes). (I) 0309 - An alternative amino acid change at the same position has been observed in gnomAD (v2) (252 heterozygotes, 0 homozygotes). (I) 0502 - Missense variant with conflicting in silico predictions and very? high conservation. (I) 0600 - Variant is located in an annotated kinase domain (PMID: 11528398). (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been observed as compound heterozygous in many individuals with GNE-related myopathy, and has also been observed as homozygous in at least three individuals with late onset myopathy (ClinVar, PMIDs: 11528398, 33250842, 27858732, 28320138). (SP) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
This variant (c. 2086G>A; p.V696M) has been previously reported as a pathogenic variant in individuals of Indian and Thai origin. It has been shown to segregate with disease in at least one family, including 3 affected and 4 unaffected individuals (Eisenberg et al 2001; Boyden et al 2011: Liewluck et al 2006; Eisenberg et al 2003). -
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This variant has been associated with GNE myopathy when in combination with a pathogenic variant on the other allele. No current reports of affected individuals het or hom for this variant. -
34 years old female, no family history, started having frequent falls at the age of 29 years of age followed by progressively increasing weakness of lower limbs. The weakness appears to be more in distal areas than proximal limb and lower limb is affected more than upper limbs. Next generation DNA sequencing of peripheral blood sample has revealed the presence of two pathogenic variants c.2086 G>A and c.1571C>T in the GNE gene consistent with the diagnosis of Nonaka myopathy or inclusion body myopathy 2/ distal myopathy with rimmed vacuoles. -
not provided Pathogenic:5
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Missense variants in this gene are a common cause of disease and they are underrepresented in the general population; In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 31561939, 25002140, 20059379, 24796702, 24695763, 24707269, 11528398, 27535533, 27829678, 20175955, 19917666, 28717665, 27457812, 24005727, 29997562, 12497639, 16810679, 25182749, 25617006, 14972325, 21708040, 29480215, 30564623, 31589614, 33250842, 37366078, 35933247, 36344503, 33197058, 34825065, 31069529, 35723113, 35398442) -
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Sialuria;C1853926:GNE myopathy Pathogenic:4
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This sequence change replaces valine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 727 of the GNE protein (p.Val727Met). This variant is present in population databases (rs121908627, gnomAD 1.4%), including at least one homozygous and/or hemizygous individual. This missense change has been observed in individual(s) with autosomal recessive GNE myopathy/distal myopathy with rimmed vacuoles (PMID: 11528398, 12497639, 20175955, 21708040, 23437777, 24005727, 25182749, 27829678, 28320138, 28717665). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. This variant is also known as p.Val696Met. ClinVar contains an entry for this variant (Variation ID: 6028). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on GNE protein function. For these reasons, this variant has been classified as Pathogenic. -
GNE-related disorder Pathogenic:2
The GNE c.2179G>A variant is predicted to result in the amino acid substitution p.Val727Met. This variant is also known as c.2086G>A, p.Val696Met using an alternative transcript NM_005476.5. This variant has been reported in many individuals in the compound heterozygous state to be causative for recessive GNE myopathy (Eisenberg et al. 2001. PubMed ID: 11528398; Chaouch et al. 2014. PubMed ID: 24695763; Boyden et al. 2011. PubMed ID: 21708040; Voermans et al. 2010. PubMed ID: 20175955). The c.2179G>A variant has a minor allele frequency of 1.36% in South Asian populations which is consistent with this variant likely being a pathogenic founder mutation in individuals of Indian and Thai descent (Nalini et al. 2013. PubMed ID: 24005727; Tanboon et al. 2014. PubMed ID: 24707269; Voermans et al. 2010. PubMed ID: 20175955). Variants in GNE are also associated with autosomal dominant sialuria (Leroy et al. 2001. PubMed ID: 11326336). Some patients with GNE myopathy were reported to have mild, asymptomatic thrombocytopenia (Mori-Yoshimura et al. 2014. PubMed ID: 25303967). Two recent studies report patients with severe congenital thrombocytopenia with no clinical evidence of GNE myopathy who harbored homozygous variants in GNE (Revel-Vilk et al. 2018. PubMed ID: 30171045; Futterer et al. 2018. PubMed ID: 29941673). In addition to large platelets, patients showed bruising and bleeding tendencies though platelet aggregation appeared to be unaffected. In summary, the c.2179G>A variant is pathogenic for recessive GNE myopathy and may also be associated with other GNE-related conditions. -
PS4, PM3, PP1 -
Sialuria Pathogenic:1
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Sialuria;C1853926:GNE myopathy;C5935593:Thrombocytopenia 12 with or without myopathy Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at