rs761439623

Positions:

• chr9-131518955-C-A
• chr9-131518955-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001077365.2(POMT1):​c.1484C>A​(p.Ala495Glu) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 18/23 in silico tools predict a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. A495A) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: POMT1 NM_001077365.2 missense, splice_region
• Scores: Splicing: ADA: 0.00001110
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.0630

Genes affected

POMT1 (HGNC:9202): (protein O-mannosyltransferase 1) The protein encoded by this gene is an O-mannosyltransferase that requires interaction with the product of the POMT2 gene for enzymatic function. The encoded protein is found in the membrane of the endoplasmic reticulum. Defects in this gene are a cause of Walker-Warburg syndrome (WWS) and limb-girdle muscular dystrophy type 2K (LGMD2K). Several transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Oct 2008]

(HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.12814903).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
POMT1	NM_001077365.2	c.1484C>A	p.Ala495Glu	missense_variant, splice_region_variant	15/20	ENST00000402686.8	NP_001070833.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
POMT1	ENST00000402686.8	c.1484C>A	p.Ala495Glu	missense_variant, splice_region_variant	15/20	1	NM_001077365.2	ENSP00000385797	P1
	ENST00000415423.1	n.63-1987G>T		intron_variant, non_coding_transcript_variant		3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Walker-Warburg congenital muscular dystrophy;C1836373:Autosomal recessive limb-girdle muscular dystrophy type 2K;C5436962:Muscular dystrophy-dystroglycanopathy (congenital with intellectual disability), type B1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 15, 2022

This sequence change replaces alanine, which is neutral and non-polar, with glutamic acid, which is acidic and polar, at codon 517 of the POMT1 protein (p.Ala517Glu). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with POMT1-related conditions. ClinVar contains an entry for this variant (Variation ID: 1476557). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. 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	Benign	0.11
BayesDel_addAF	Benign	-0.091	T
BayesDel_noAF	Benign	-0.37
CADD	Benign	0.35
DANN	Benign	0.92
DEOGEN2	Benign	0.13	.;.;.;T;.;T
Eigen	Benign	-1.6
Eigen_PC	Benign	-1.7
FATHMM_MKL	Benign	0.14	N
LIST_S2	Uncertain	0.90	D;D;D;D;.;D
M_CAP	Benign	0.072	D
MetaRNN	Benign	0.13	T;T;T;T;T;T
MetaSVM	Benign	-0.73	T
MutationAssessor	Benign	0.34	.;.;.;N;.;.
MutationTaster	Benign	1.0	N;N;N;N;N;N;N;N
PrimateAI	Benign	0.22	T
PROVEAN	Benign	0.66	N;N;N;N;N;N
REVEL	Benign	0.21
Sift	Benign	0.17	T;T;T;T;T;T
Sift4G	Benign	0.13	T;T;T;T;T;T
Polyphen		0.019, 0.0050	.;B;.;B;B;.
Vest4		0.19
MutPred		0.47		.;.;.;Loss of loop (P = 0.0374);.;.;
MVP		0.59
MPC		0.29
ClinPred		0.058	T
GERP RS		-11
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.037
gMVP		0.26

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.000011
dbscSNV1_RF	Benign	0.080
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: rs761439623; hg19: chr9-134394342;