14-77277452-C-T

Variant names:

• chr14-77277452-C-T
• rs267606969
• NM_013382.7:c.2177G>A

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM2 PM5 PP3_Strong PP5_Moderate

The NM_013382.7(POMT2):​c.2177G>A​(p.Gly726Glu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,648 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 Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G726R) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: POMT2 NM_013382.7 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:3
• Conservation: PhyloP100: 7.62
• Publications: 4 publications found

Genes affected

POMT2 (HGNC:19743): (protein O-mannosyltransferase 2) The protein encoded by this gene is an O-mannosyltransferase that requires interaction with the product of the POMT1 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).[provided by RefSeq, Oct 2008]

POMT2 Gene-Disease associations (from GenCC):

• muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A2

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• myopathy caused by variation in POMT2

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• muscular dystrophy-dystroglycanopathy (congenital with intellectual disability), type B2

  Inheritance: AR Classification: MODERATE Submitted by: Ambry Genetics
• autosomal recessive limb-girdle muscular dystrophy type 2N

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• congenital muscular dystrophy with cerebellar involvement

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• congenital muscular dystrophy with intellectual disability

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• muscle-eye-brain disease

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• muscular dystrophy-dystroglycanopathy, type A

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 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 chr14-77277453-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 1397473.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.982
• PP5: Variant 14-77277452-C-T is Pathogenic according to our data. Variant chr14-77277452-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 3222.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
POMT2	NM_013382.7	c.2177G>A	p.Gly726Glu	missense_variant	Exon 21 of 21	ENST00000261534.9	NP_037514.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
POMT2	ENST00000261534.9	c.2177G>A	p.Gly726Glu	missense_variant	Exon 21 of 21	1	NM_013382.7	ENSP00000261534.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461648 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727152

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111790

Other (OTH) AF: 0.00 AC: 0 AN: 60388

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, single submitter

Submissions by phenotype

Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A2;C3150416:Muscular dystrophy-dystroglycanopathy (congenital with intellectual disability), type B2;C3150418:Autosomal recessive limb-girdle muscular dystrophy type 2N Pathogenic:1

Oct 30, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with glutamic acid, which is acidic and polar, at codon 726 of the POMT2 protein (p.Gly726Glu). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with alpha-dystroglycanopathy (PMID: 16701995, 17878207, 22700954). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 3222). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on POMT2 protein function. This variant disrupts the p.Gly726 amino acid residue in POMT2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 17559086, 34413876). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Muscular dystrophy-dystroglycanopathy (congenital with intellectual disability), type B2 Pathogenic:1

May 26, 2009

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A2 Pathogenic:1

Jul 01, 2006

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.48	D
BayesDel_noAF	Pathogenic	0.45
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.94	D
Eigen	Uncertain	0.65
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.42	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.1	H
PhyloP100		7.6
PrimateAI	Uncertain	0.75	T
PROVEAN	Pathogenic	-6.5	D
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.99
MutPred		0.84		Gain of catalytic residue at H721 (P = 0.0118);
MVP		0.97
MPC		0.52
ClinPred		1.0	D
GERP RS		5.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.97
gMVP		0.96
Mutation Taster		=1/99	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.090		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs267606969; hg19: chr14-77743795;