rs367543075
Variant summary
Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_152490.5(B3GALNT2):c.824_825dupTT(p.Ile276LeufsTer26) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000276 in 1,613,952 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.
Frequency
Consequence
NM_152490.5 frameshift
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 18 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000125 AC: 19AN: 152146Hom.: 0 Cov.: 31
GnomAD3 exomes AF: 0.000211 AC: 53AN: 251380Hom.: 0 AF XY: 0.000236 AC XY: 32AN XY: 135862
GnomAD4 exome AF: 0.000292 AC: 427AN: 1461806Hom.: 0 Cov.: 31 AF XY: 0.000257 AC XY: 187AN XY: 727206
GnomAD4 genome AF: 0.000125 AC: 19AN: 152146Hom.: 0 Cov.: 31 AF XY: 0.0000942 AC XY: 7AN XY: 74322
ClinVar
Submissions by phenotype
Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type a, 11 Pathogenic:6
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This sequence change creates a premature translational stop signal (p.Ile276Leufs*26) in the B3GALNT2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in B3GALNT2 are known to be pathogenic (PMID: 23453667). This variant is present in population databases (rs367543075, gnomAD 0.04%). This premature translational stop signal has been observed in individual(s) with congenital muscular dystrophy and/or congenital muscular dystrophy-dystroglycanopathy (PMID: 23453667, 29273094). It has also been observed to segregate with disease in related individuals. This variant is also known as c.822_823dup. ClinVar contains an entry for this variant (Variation ID: 132981). For these reasons, this variant has been classified as Pathogenic. -
Variant summary: B3GALNT2 c.824_825dupTT (p.Ile276LeufsX26) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant allele was found at a frequency of 0.00021 in 251380 control chromosomes (gnomAD). c.824_825dupTT has been reported in the literature in the compound heterozygous state in individuals affected with and/or with features of Muscular Dystrophy-Dystroglycanopathy (congenital With Brain And Eye Anomalies) and in two siblings presenting with mild intellectual disability and behavioral problems but without muscular involvement (e.g. Stevens_2013, Maroofian_2017, Marangoni_2022). These data indicate that the variant is likely to be associated with disease. A publication reporting experimental evidence evaluating an impact on protein function found the variant failed to restore IIH6 staining in a complementation assay, resulting in <10% of WT activity (Maroofian_2017). Five submitters have provided clinical-significance assessments for this variant to ClinVar after 2014 and all classified the variant as pathogenic (n=4)/likely pathogenic (n=1). Based on the evidence outlined above, the variant was classified as pathogenic. -
second B3GALNT2 in trans (Missense-Variant, VUS) -
not provided Pathogenic:2Other:1
Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 29273094, 35456500, 31980526, 34906519, 23453667) -
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B3GALNT2-related disorder Pathogenic:1
The B3GALNT2 c.824_825dupTT variant is predicted to result in a frameshift and premature protein termination (p.Ile276Leufs*26). This variant has been reported in the compound heterozygous state to be causative for dystroglycanopathy in two unrelated families (Stevens et al. 2013. PubMed ID: 23453667; Maroofian et al. 2017. PubMed ID: 29273094). This variant is reported in 0.043% of alleles in individuals of European (Non-Finnish) descent in gnomAD. Frameshift variants in B3GALNT2 are expected to be pathogenic, and this variant has been interpreted as pathogenic by multiple independent submitters to the ClinVar database (https://www.ncbi.nlm.nih.gov/clinvar/variation/132981). Given all the evidence, we too interpret c.824_825dup (p.Ile276Leufs*26) as pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at