Submissions for variant NM_001244710.2(GFPT1):c.686-2A>G

gnomAD frequency: 0.00002  dbSNP: rs1011196447

Total submissions: 10

Submitter	RCV	SCV	Clinical significance	Condition	Last evaluated	Review status	Method	Comment
Labcorp Genetics (formerly Invitae), Labcorp	RCV000650361	SCV000772204	pathogenic	Congenital myasthenic syndrome 12	2024-01-23	criteria provided, single submitter	clinical testing	This sequence change affects an acceptor splice site in intron 8 of the GFPT1 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and may result in an absent or disrupted protein product. RNA analysis indicates that disruption of this splice site induces altered splicing and may result in an absent or disrupted protein product. This variant is present in population databases (no rsID available, gnomAD 0.02%). Disruption of this splice site has been observed in individuals with congenital myasthenic syndrome (PMID: 23794683, 28464723, 29054425). ClinVar contains an entry for this variant (Variation ID: 540353). Studies have shown that disruption of this splice site results in deletion of the first 4 nucleotides of the muscle-specific exon of GFPT1 and introduces a premature termination codon (PMID: 23794683). The resulting mRNA is expected to undergo nonsense-mediated decay. For these reasons, this variant has been classified as Pathogenic.
Kariminejad - Najmabadi Pathology & Genetics Center	RCV001836857	SCV000927078	pathogenic	Abnormality of the musculature	2021-07-10	criteria provided, single submitter	clinical testing
Pars Genome Lab	RCV000650361	SCV001960986	pathogenic	Congenital myasthenic syndrome 12	2021-10-04	criteria provided, single submitter	clinical testing
3billion	RCV000650361	SCV002058686	pathogenic	Congenital myasthenic syndrome 12	2022-01-03	criteria provided, single submitter	clinical testing	Canonical splice site: predicted to alter splicing and result in a loss or disruption of normal protein function through protein truncation. Multiple pathogenic variants are reported in the predicted truncated region (PVS1_VS).The variant has been reported at least twice as pathogenic/likely pathogenic with clinical assertions and evidence for the classification (ClinVar ID: VCV000540353). It is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.000024, PM2_M). The variant has been reported to be in trans with a pathogenic variant as either compound heterozygous or homozygous in at least one similarly affected unrelated individual (PMID:23794683, PM3_M). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline.
Illumina Laboratory Services, Illumina	RCV002260516	SCV002540253	pathogenic	GFPT1-related myasthenic syndrome	2022-01-04	criteria provided, single submitter	clinical testing	The GFPT1 c.686-2A>G variant results in the substitution of an adenine within the consensus splice acceptor site with a guanine, which may result in splicing defects. Across a selection of the available literature, this variant has been identified in at least five individuals with a congenital myasthenic syndrome or limb-girdle muscle weakness, including in a confirmed or presumed homozygous state in four individuals, and in a compound heterozygous state in one individual (Selcen et al. 2013; Yiş et al. 2017; Natera-de Benito et al. 2017; Gonzalez-Quereda et al. 2020; Töpf et al. 2020). The highest frequency of this allele in the Genome Aggregation Database is 0.000148 in the Latino/Admixed American population (version 2.1.1). This variant precedes the muscle-specific exon of GFPT1, and patient cDNA studies have shown that it eliminates the first four nucleotides of this exon and results in missense changes of 56 amino acids and a premature stop codon (Selcen et al. 2013). This variant was identified in a homozygous state. Based on the available evidence, the c.686-2A>G variant is classified as pathogenic for GFPT1-related myasthenic syndrome.
Fulgent Genetics, Fulgent Genetics	RCV002507119	SCV002813973	pathogenic	Congenital myasthenic syndrome 4C; Congenital myasthenic syndrome 12	2022-05-12	criteria provided, single submitter	clinical testing
Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard	RCV000650361	SCV003922366	pathogenic	Congenital myasthenic syndrome 12	2023-05-02	criteria provided, single submitter	curation	The homozygous c.686-2A>G variant in GFPT1 was identified by our study in one individual with congenital myasthenic syndrome. The c.686-2A>G variant in GFPT1 has been previously reported in at least four unrelated individuals with congenital myasthenic syndrome 12 (PMID: 28464723, PMID: 29054425, PMID: 32403337, PMID: 32528171, PMID: 23794683) but has been identified in 0.015% (5/33776) of Latino/Admixed American chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP ID: rs772941684). 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. This variant has also been reported in ClinVar (Variation ID: 540353) and has been interpreted as pathogenic by Invitae, Illumina, 3billion, Pars Genome Lab, and Kariminejad - Najmabadi Pathology & Genetics Center. Of these four individuals with congenital myasthenic syndrome 12 (PMID: 28464723, PMID: 29054425, PMID: 32403337, PMID: 32528171, PMID: 23794683), three were homozygotes (PMID: 28464723, PMID: 29054425, PMID: 32403337, PMID: 32528171) and one was a compound heterozygote who carried a likely pathogenic variant in trans (PMID: 23794683, ClinVar Variation ID: 859066), which increases the likelihood that the c.686-2A>G variant is pathogenic. RT-PCR and cDNA analysis of patient muscle tissue showed that the c.686-2A>G variant resulted in a 4 base-pair deletion of the muscle-specific exon of GFPT1, leading to frameshift and a premature stop codon 56 amino acids downstream (PMID: 23794683). 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 GFPT1 gene is strongly associated to autosomal recessive congenital myasthenic syndrome 12. In summary, this variant meets criteria to be classified as pathogenic for autosomal recessive congenital myasthenic syndrome 12. ACMG/AMP Criteria applied: PVS1_Strong, PM3_Strong, PS3_Supporting (Richards 2015).
CeGaT Center for Human Genetics Tuebingen	RCV003334001	SCV004042075	pathogenic	not provided	2023-09-01	criteria provided, single submitter	clinical testing	GFPT1: PVS1, PM3, PM2:Supporting, PS3:Supporting
PreventionGenetics, part of Exact Sciences	RCV003392496	SCV004119360	pathogenic	GFPT1-related disorder	2023-05-10	criteria provided, single submitter	clinical testing	The GFPT1 c.686-2A>G variant is predicted to disrupt the AG splice acceptor site and interfere with normal splicing. This variant has been reported in the homozygous or compound heterozygous state in multiple individuals with congenital myasthenic syndrome (see for example, Selcen et al. 2013. PubMed ID: 23794683; Yiş U et al. 2017. PubMed ID: 28464723; Natera-de Benito et al. 2017. PubMed ID: 29054425). In vitro functional study suggests this variant impacts protein function (Patient 6 in Figure 3, Selcen et al. 2013. PubMed ID: 23794683). This variant is reported in 0.015% of alleles in individuals of Latino descent in gnomAD (http://gnomad.broadinstitute.org/variant/2-69581446-T-C). Variants that disrupt the consensus splice acceptor site in GFPT1 are expected to be pathogenic. This variant is interpreted as pathogenic..
Revvity Omics, Revvity	RCV000650361	SCV004236841	pathogenic	Congenital myasthenic syndrome 12	2023-06-15	criteria provided, single submitter	clinical testing