rs192044702
Variant summary
Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1PP5_Very_Strong
The NM_000158.4(GBE1):c.691+2T>C variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00101 in 1,502,074 control chromosomes in the GnomAD database, with no homozygous occurrence. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).
Frequency
Consequence
NM_000158.4 splice_donor, intron
Scores
Clinical Significance
Conservation
Publications
- glycogen storage disease due to glycogen branching enzyme deficiencyInheritance: AR Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Laboratory for Molecular Medicine, Ambry Genetics, G2P, ClinGen
- adult polyglucosan body diseaseInheritance: AR Classification: MODERATE, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics
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ACMG classification
Our verdict: Pathogenic. The variant received 16 ACMG points.
Transcripts
RefSeq
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| GBE1 | ENST00000429644.7 | c.691+2T>C | splice_donor_variant, intron_variant | Intron 5 of 15 | 1 | NM_000158.4 | ENSP00000410833.2 | |||
| GBE1 | ENST00000489715.1 | c.568+2T>C | splice_donor_variant, intron_variant | Intron 5 of 15 | 2 | ENSP00000419638.1 | ||||
| GBE1 | ENST00000498468.1 | n.219+2T>C | splice_donor_variant, intron_variant | Intron 2 of 3 | 3 | |||||
| GBE1 | ENST00000486920.1 | n.*113T>C | downstream_gene_variant | 3 |
Frequencies
GnomAD3 genomes AF: 0.000756 AC: 115AN: 152098Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.000895 AC: 173AN: 193326 AF XY: 0.000797 show subpopulations
GnomAD4 exome AF: 0.00103 AC: 1396AN: 1349858Hom.: 0 Cov.: 22 AF XY: 0.000989 AC XY: 661AN XY: 668278 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000756 AC: 115AN: 152216Hom.: 0 Cov.: 32 AF XY: 0.000605 AC XY: 45AN XY: 74402 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Pathogenic:14
Identified in patients with features of GBE1-related glycogen storage disease or GBE1-related polyglucosan body disease referred for genetic testing at GeneDx or in published literature (PMID: 23218673, 19813197, 28507268); Canonical splice site variant predicted to result in a null allele in a gene for which loss of function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 33060286, 34626176, 33879512, 23352160, 23218673, 25489661, 28507268, 31980526, 31862442, 30569318, 29379554, 31589614, 33726816, 32528171, 33332610, 31127727, 32668698, 34426522, 33820833, 35627109, 37273706, 37301908, 26166723, 19813197) -
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GBE1: PM3:Very Strong, PVS1, PM2, PP1:Moderate -
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PP1, PP3, PS3, PS4_moderate, PVS1 -
Glycogen storage disease, type IV Pathogenic:10
The c.691+2T>C variant in GBE1 has been reported in at least 10 individuals with GBE1-related disorders (PMID: 19813197, 23218673, 25489661, 26166723, 26886200, 28507268, 29379554, 30569318, Akman 2015, Thomsen 2016) and has been identified in 0.1% (160/110918) of European (non-Finnish) chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP ID: rs192044702). Although this variant has been seen in the general population in a heterozygous state, its frequency is not high enough to rule out a pathogenic role. Of the many affected individuals, 1 was a compound heterozygote that carried a reported likely pathogenic variant in trans, and 2 were compound heterozygotes that carried a reported pathogenic variant with unknown phase, which increases the likelihood that the c.691+2T>C variant is pathogenic (Variation ID#: 2777; PMID: 25489661, 28507268, Akman 2015). This variant has also been reported in ClinVar (Variation ID#: 208584) and has been interpreted as pathogenic by multiple submitters. The phenotype of individuals homozygous or compound heterozygous for this variant is highly specific for GBE1-related disorders based on strict biochemical investigations consistent with disease (PMID: 19813197, 23218673). This variant is located in the 3' splice region. Computational tools predict a splicing impact, though this information is not predictive enough to determine pathogenicity. Loss of function of the GBE1 gene is an established disease mechanism in autosomal recessive GBE1-related disorders. In summary, this variant meets criteria to be classified as pathogenic for autosomal recessive GBE1-related disorders. ACMG/AMP Criteria applied: PVS1, PM3_strong, PP4 (Richards 2015). -
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This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -
This variant affects the canonical splice donor site of intron 5 of 15, and is therefore predicted to interfere with splicing and result in loss of normal protein function. This variant has been previously reported as a compound heterozygous change in patients with GBE1 glycogen storage disease (PMID: 23218673, 19813197). It is present in the heterozygous state in the gnomAD population database at a frequency of 0.082% (183/223430; max AF: 0.0013 in European populations) and thus is presumed to be rare. Multiple splice prediction tools suggest this variant is likely to interfere with normal splicing. Based on the available evidence, the c.691+2T>C variant is classified as Pathogenic. -
This variant was classified as: Pathogenic. The following ACMG criteria were applied in classifying this variant: PVS1,PM2,PP5. -
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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 glycogen storage disease IV (GSD-IV) (MIM#232500) and adult form polyglucosan body disease (MIM#263570). (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0211 - Canonical splice site variant without proven consequence on splicing (no functional evidence available). (SP) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD (v2) <0.01 for a recessive condition (194 heterozygotes, 0 homozygotes). (SP) 0505 - Abnormal splicing is predicted by in silico tools and affected nucleotide is highly conserved. (SP) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been reported as pathogenic in multiple patients with either GSD-IV or adult form polyglucosan body disease (LOVD, ClinVar, PMID: 29379554). (SP) 1207 - Parental origin of the variant is unresolved. The proband and both parents are heterozygous for this variant (by trio analysis). (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
Variant summary: GBE1 c.691+2T>C is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: four predict the variant abolishes a 5' splicing donor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.00089 in 193326 control chromosomes. This frequency is not significantly higher than expected for a pathogenic variant in GBE1 causing Glycogen Storage Disease, Type IV (0.00089 vs 0.0013), allowing no conclusion about variant significance. c.691+2T>C has been reported in the literature in several compound heterozygous individuals affected with Glycogen Storage Disease, Type IV (e.g. Fernandez_2010, Ravenscroft_2013, Bendroth-Asmussen_2016, Schene_2018, Szymanska_2018). These data indicate that the variant is likely to be associated with disease. Several publications also reported severely reduced enzyme activities in patient derived cells (e.g. Fernandez_2010, Ravenscroft_2013, Schene_2018, Szymanska_2018). 13 submitters have provided clinical-significance assessments for this variant in ClinVar after 2014, and all of them classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
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GBE1-related disorder Pathogenic:2
The GBE1 c.691+2T>C splice donor variant has been reported in a total of seven individuals, including five with glycogen storage disease type IV (GSD IV) and two with adult polyglucosan body disease (APBD) (Fernandez et al. 2010; Ravenscroft et al. 2013; Bendroth-Asmussen et al. 2016; Kuhn et al. 2016; Franco-Palacios et al. 2016; Lopez Chiriboga 2017). All five individuals with GSD IV and one individual with APBD were compound heterozygous for the variant. In addition, one individual with APBD was heterozygous for the c.691+2T>C variant and homozygous for another intronic variant in the GBE1 gene (Franco-Palacios et al. 2016). The c.691+2T>C variant was also identified in a heterozygous state in two unaffected individuals (Ravenscroft et al. 2013; Dainese et al. 2014). Control data are unavailable for this variant, which is reported at a frequency of 0.00196 in the European (non-Finnish) population of the Exome Aggregation Consortium. Two studies noted significantly reduced GBE enzyme activity in individual fibroblasts (Fernandez et al. 2010; Ravenscroft et al. 2013). Based on the evidence and due to the potential impact of splice donor variants, the p.691+2T>C variant is classified as pathogenic for GBE1-related disorders. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -
The GBE1 c.691+2T>C variant is predicted to disrupt the GT donor site and interfere with normal splicing. This variant has been reported in the compound heterozygous state in two presumably unrelated families, one of which included siblings initially diagnosed with lethal multiple pterygium syndrome (Fernandez et al. 2010. PubMed ID: 19813197; Ravenscroft et al. 2013. PubMed ID: 23218673). More recently, this variant was identified in the compound heterozygous state with a second pathogenic GBE1 variant in tissue from a fetus lost in a first trimester miscarriage. Histopathological findings in the fetal tissue were consistent with glycogen storage disease type IV (GSD IV) (Bendroth-Asmussen et al. 2016. PubMed ID: 26166723). At PreventionGenetics, we have observed this variant in combination with a second pathogenic variant in at least two unrelated affected patients. This variant is reported in 0.14% of alleles in individuals of European (Non-Finnish) descent in gnomAD (http://gnomad.broadinstitute.org/variant/3-81698005-A-G). Variants that disrupt the consensus splice donor site in GBE1 are expected to be pathogenic. This variant is interpreted as pathogenic. -
Glycogen storage disease, type IV;C1849722:Adult polyglucosan body disease Pathogenic:1
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Inborn genetic diseases Pathogenic:1
The c.691+2T>C intronic alteration results from a T to C substitution two nucleotides after coding exon 5 of the GBE1 gene. Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay; however, +2T>C alterations are capable of generating wild-type transcripts in some genomic contexts and should be interpreted with caution (Lin, 2019). Based on data from gnomAD, the C allele has an overall frequency of 0.086% (194/224704) total alleles studied. The highest observed frequency was 0.144% (160/110918) of European (non-Finnish) alleles. This variant has been identified in the homozygous state and likely in trans with another GBE1 variant in multiple individuals and fetuses with features consistent with neuromuscular subtypes of GBE1-related glycogen storage disease, including biochemical or histological confirmation (Fernandez, 2010; Ravenscroft, 2013; Bendroth-Asmussen, 2016; Schene, 2019; Lefèvre, 2023). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice donor site. Based on the available evidence, this alteration is classified as pathogenic. -
Dementia Pathogenic:1
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Glycogen storage disease Pathogenic:1
The c.691+2T>C variant in GBE1 has been reported in at least 3 compound heterozygous individuals with glycogen storage disease IV and segregated with disease in at least 2 affected relatives from 1 family (Fernandez 2010 PMID:19813197, Ravenscroft 2013 PMID:23218673, Schene 2018 PMID:30569318). It has also been reported in ClinVar (Variation ID 208584) and has been identified in 0.14% (160/110918) of European chromosomes by gnomAD (http://gnomad.broadinstitute.org). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. This variant occurs within the canonical splice site (+/- 1,2) and is predicted to cause altered splicing leading to an abnormal or absent protein. Loss of function of the GBE1 gene is an established disease mechanism in autosomal recessive glycogen storage disease IV. In summary, this variant meets criteria to be classified as pathogenic for autosomal recessive glycogen storage disease IV. ACMG/AMP Criteria applied: PVS1, PM3_Strong, PP1_Moderate. -
Adult polyglucosan body disease Pathogenic:1
Criteria applied: PVS1,PM3_VSTR,PM2_SUP -
Arthrogryposis syndrome Pathogenic:1
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Glycogen storage disease, type IV;C1856301:Glycogen storage disease IV, classic hepatic Pathogenic:1
This sequence change affects a donor splice site in intron 5 of the GBE1 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in GBE1 are known to be pathogenic (PMID: 15452297, 20058079). This variant is present in population databases (rs192044702, gnomAD 0.1%), and has an allele count higher than expected for a pathogenic variant. Disruption of this splice site has been observed in individual(s) with glycogen storage disease type IV (PMID: 19813197, 23218673, 26166723, 30569318). 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. ClinVar contains an entry for this variant (Variation ID: 208584). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at