rs367543075

chr1-235465651-T-TAA

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_152490.5(B3GALNT2):c.825_826insTT(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:
  • Genomes: 𝑓 0.00012 (0 hom., cov: 31)
  • Exomes 𝑓: 0.00029 (0 hom.)
• Consequence: B3GALNT2 NM_152490.5 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8 O:1
• Conservation: PhyloP100: 0.678

Genes affected

B3GALNT2 (HGNC:28596): (beta-1,3-N-acetylgalactosaminyltransferase 2) This gene encodes a member of the glycosyltransferase 31 family. The encoded protein synthesizes GalNAc:beta-1,3GlcNAc, a novel carbohydrate structure, on N- and O-glycans. Alternatively spliced transcript variants that encode different isoforms have been described. [provided by RefSeq, Mar 2013]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-235465651-T-TAA is Pathogenic according to our data. Variant chr1-235465651-T-TAA is described in ClinVar as [Likely_pathogenic]. Clinvar id is 132981.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
B3GALNT2	NM_152490.5	c.825_826insTT	p.Ile276LeufsTer26	frameshift_variant	7/12	ENST00000366600.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
B3GALNT2	ENST00000366600.8	c.825_826insTT	p.Ile276LeufsTer26	frameshift_variant	7/12	1	NM_152490.5	P1

Frequencies

GnomAD3 genomes AF: 0.000125 AC: 19 AN: 152146 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000265

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000211 AC: 53 AN: 251380 Hom.: 0 AF XY: 0.000236 AC XY: 32 AN XY: 135862

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000578

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.0000924

Gnomad NFE exome AF: 0.000431

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000292 AC: 427 AN: 1461806 Hom.: 0 Cov.: 31 AF XY: 0.000257 AC XY: 187 AN XY: 727206

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.000131

Gnomad4 NFE exome AF: 0.000363

Gnomad4 OTH exome AF: 0.000232

GnomAD4 genome AF: 0.000125 AC: 19 AN: 152146 Hom.: 0 Cov.: 31 AF XY: 0.0000942 AC XY: 7 AN XY: 74322

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000265

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000291 Hom.: 0

EpiCase AF: 0.000109

EpiControl AF: 0.000237

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type a, 11 Pathogenic:6

Pathogenic, criteria provided, single submitter	clinical testing	Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen	Feb 28, 2024	second B3GALNT2 in trans (Missense-Variant, VUS) -
Likely pathogenic, criteria provided, single submitter	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	May 31, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 28, 2024	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. -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Mar 30, 2023	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. -
Pathogenic, criteria provided, single submitter	clinical testing	Genome Diagnostics Laboratory, Amsterdam University Medical Center	Oct 12, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Sep 05, 2019	- -

not provided Pathogenic:2 Other:1

not provided, no classification provided	literature only	Leiden Muscular Dystrophy pages (B3GALNT2)	-	- -
Pathogenic, no assertion criteria provided	clinical testing	Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Aug 24, 2023	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) -

Computational scores

Source: dbNSFP v4.3

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs367543075; hg19: chr1-235628968;