2-74461288-GC-G

Variant names:

• chr2-74461288-GC-G
• rs1296169573
• NM_006302.3:c.2500delG

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_006302.3(MOGS):​c.2500delG​(p.Ala834LeufsTer21) variant causes a frameshift change. The variant allele was found at a frequency of 0.000000684 in 1,461,738 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MOGS NM_006302.3 frameshift
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.12

Genes affected

MOGS (HGNC:24862): (mannosyl-oligosaccharide glucosidase) This gene encodes the first enzyme in the N-linked oligosaccharide processing pathway. The enzyme cleaves the distal alpha-1,2-linked glucose residue from the Glc(3)-Man(9)-GlcNAc(2) oligosaccharide precursor. This protein is located in the lumen of the endoplasmic reticulum. Defects in this gene are a cause of type IIb congenital disorder of glycosylation (CDGIIb). Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Mar 2009]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.00557 CDS is truncated, and there are 0 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MOGS	NM_006302.3	c.2500delG	p.Ala834LeufsTer21	frameshift_variant	Exon 4 of 4	ENST00000448666.7	NP_006293.2
MOGS	NM_001146158.2	c.2182delG	p.Ala728LeufsTer21	frameshift_variant	Exon 5 of 5		NP_001139630.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MOGS	ENST00000448666.7	c.2500delG	p.Ala834LeufsTer21	frameshift_variant	Exon 4 of 4	1	NM_006302.3	ENSP00000410992.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000402 AC: 1 AN: 248998 Hom.: 0 AF XY: 0.00000739 AC XY: 1 AN XY: 135286

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000290

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461738 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727168

Gnomad4 AFR exome AF: 0.00

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: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

MOGS-congenital disorder of glycosylation Uncertain:1

May 03, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Ala834Leufs*21) in the MOGS gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 4 amino acid(s) of the MOGS protein. This variant is present in population databases (no rsID available, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with MOGS-related conditions. ClinVar contains an entry for this variant (Variation ID: 638889). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs1296169573; hg19: chr2-74688415;