1-46193873-C-G

Position:

• chr1-46193873-C-G

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM2 PM5 PP3_Strong PP5_Moderate

The NM_017739.4(POMGNT1):​c.932G>C​(p.Arg311Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,788 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 Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R311Q) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: POMGNT1 NM_017739.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.39

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]

TSPAN1 (HGNC:20657): (tetraspanin 1) The protein encoded by this gene is a member of the transmembrane 4 superfamily, also known as the tetraspanin family. Most of these members are cell-surface proteins that are characterized by the presence of four hydrophobic domains. The proteins mediate signal transduction events that play a role in the regulation of cell development, activation, growth and motility. [provided by RefSeq, Jul 2008]

POMGNT1 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-46193873-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 3993.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984
• PP5: Variant 1-46193873-C-G is Pathogenic according to our data. Variant chr1-46193873-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2927335.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
POMGNT1	NM_017739.4	c.932G>C	p.Arg311Pro	missense_variant	10/22	ENST00000371984.8	NP_060209.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
POMGNT1	ENST00000371984.8	c.932G>C	p.Arg311Pro	missense_variant	10/22	1	NM_017739.4	ENSP00000361052.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251316 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135826

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461788 Hom.: 0 Cov.: 35 AF XY: 0.00000138 AC XY: 1 AN XY: 727182

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Alfa AF: 0.0000425 Hom.: 0

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 29, 2023

This variant disrupts the p.Arg311 amino acid residue in POMGNT1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 15236414, 17030669, 21361872, 22323514). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. 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 expected to disrupt POMGNT1 protein function. This variant has not been reported in the literature in individuals affected with POMGNT1-related conditions. This variant is present in population databases (rs193919336, gnomAD 0.0009%). This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 311 of the POMGNT1 protein (p.Arg311Pro). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.44
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.97	D;.
Eigen	Pathogenic	0.93
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	0.97	D;D
M_CAP	Pathogenic	0.42	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Pathogenic	3.5	M;M
PrimateAI	Uncertain	0.78	T
PROVEAN	Pathogenic	-6.2	D;D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D;D
Sift4G	Uncertain	0.0090	D;D
Polyphen		1.0	D;.
Vest4		0.98
MutPred		0.91		Gain of glycosylation at R311 (P = 0.0205);Gain of glycosylation at R311 (P = 0.0205);
MVP		0.97
MPC		1.1
ClinPred		0.99	D
GERP RS		5.0
Varity_R		0.99
gMVP		0.97

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: rs193919336; hg19: chr1-46659545;