rs17102066

Positions:

• chr1-46192127-C-A
• chr1-46192127-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The NM_017739.4(POMGNT1):​c.1510G>T​(p.Val504Phe) variant causes a missense change. The variant allele was found at a frequency of 0.00000205 in 1,461,836 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. V504I) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: POMGNT1 NM_017739.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.76

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:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_017739.4
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
POMGNT1	NM_017739.4	c.1510G>T	p.Val504Phe	missense_variant	17/22	ENST00000371984.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
POMGNT1	ENST00000371984.8	c.1510G>T	p.Val504Phe	missense_variant	17/22	1	NM_017739.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251454 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135904

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: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461836 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727224

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain: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 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 24, 2021

This sequence change replaces valine with phenylalanine at codon 504 of the POMGNT1 protein (p.Val504Phe). The valine residue is highly conserved and there is a small physicochemical difference between valine and phenylalanine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with POMGNT1-related conditions. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.34
BayesDel_addAF	Uncertain	0.11	D
BayesDel_noAF	Uncertain	0.010
CADD	Benign	20
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.56	D;.
Eigen	Benign	0.17
Eigen_PC	Benign	0.19
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.87	D;D
M_CAP	Uncertain	0.10	D
MetaRNN	Uncertain	0.68	D;D
MetaSVM	Uncertain	-0.13	T
MutationAssessor	Benign	1.3	L;L
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Uncertain	0.77	T
PROVEAN	Benign	-1.1	N;N
REVEL	Uncertain	0.52
Sift	Benign	0.17	T;T
Sift4G	Benign	0.28	T;T
Polyphen		0.88	P;.
Vest4		0.65
MutPred		0.52		Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);
MVP		0.93
MPC		0.33
ClinPred		0.49	T
GERP RS		5.2
Varity_R		0.30
gMVP		0.77

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: rs17102066; hg19: chr1-46657799;