chr1-46197020-C-T

Variant names:

• chr1-46197020-C-T
• rs779506923
• NM_017739.4:c.185G>A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_017739.4(POMGNT1):​c.185G>A​(p.Arg62Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000015 in 1,461,872 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R62G) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000015 (0 hom.)
• Consequence: POMGNT1 NM_017739.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 7.33

Genes affected

POMGNT1 (HGNC:19139): (protein O-linked mannose N-acetylglucosaminyltransferase 1 (beta 1,2-)) This gene encodes a type II transmembrane protein that resides in the Golgi apparatus. It participates in O-mannosyl glycosylation and is specific for alpha linked terminal mannose. Mutations in this gene may be associated with muscle-eye-brain disease and several congenital muscular dystrophies. Alternatively spliced transcript variants that encode different protein isoforms have been described. [provided by RefSeq, Feb 2014]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.751

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
POMGNT1	NM_017739.4	c.185G>A	p.Arg62Gln	missense_variant	Exon 3 of 22	ENST00000371984.8	NP_060209.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
POMGNT1	ENST00000371984.8	c.185G>A	p.Arg62Gln	missense_variant	Exon 3 of 22	1	NM_017739.4	ENSP00000361052.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000318 AC: 8 AN: 251492 Hom.: 0 AF XY: 0.0000368 AC XY: 5 AN XY: 135920

Gnomad AFR exome AF: 0.0000615

Gnomad AMR exome AF: 0.000116

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: 0.0000264

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000150 AC: 22 AN: 1461872 Hom.: 0 Cov.: 33 AF XY: 0.0000179 AC XY: 13 AN XY: 727242

Gnomad4 AFR exome AF: 0.0000896

Gnomad4 AMR exome AF: 0.0000894

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000117

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ExAC AF: 0.0000330 AC: 4

EpiCase AF: 0.00

EpiControl AF: 0.000119

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Muscular dystrophy-dystroglycanopathy (congenital with intellectual disability), type B3;C3150417:Autosomal recessive limb-girdle muscular dystrophy type 2O Uncertain:1

Jul 12, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 62 of the POMGNT1 protein (p.Arg62Gln). This variant is present in population databases (rs779506923, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with POMGNT1-related conditions. ClinVar contains an entry for this variant (Variation ID: 968226). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt POMGNT1 protein function. 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. -

not provided Uncertain:1

Jun 18, 2021

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Muscle eye brain disease Uncertain:1

Jun 18, 2020

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.038	T
BayesDel_noAF	Uncertain	-0.070
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.025	T;T;.
Eigen	Benign	0.073
Eigen_PC	Benign	-0.0089
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Pathogenic	0.98	D;D;D
M_CAP	Uncertain	0.10	D
MetaRNN	Pathogenic	0.75	D;D;D
MetaSVM	Uncertain	-0.11	T
MutationAssessor	Uncertain	2.0	.;M;M
PrimateAI	Uncertain	0.69	T
PROVEAN	Benign	-0.73	N;N;N
REVEL	Uncertain	0.38
Sift	Benign	0.048	D;D;D
Sift4G	Benign	0.34	T;T;T
Polyphen		1.0	D;D;.
Vest4		0.85
MutPred		0.57		Gain of helix (P = 0.132);Gain of helix (P = 0.132);Gain of helix (P = 0.132);
MVP		0.80
MPC		0.38
ClinPred		0.28	T
GERP RS		3.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.14
gMVP		0.70

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: rs779506923; hg19: chr1-46662692;