9-131504244-T-C

Variant names:

• chr9-131504244-T-C
• rs1945225387
• NM_001077365.2:c.26T>C

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The NM_001077365.2(POMT1):​c.26T>C​(p.Val9Ala) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,880 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: POMT1 NM_001077365.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.29
• Publications: 0 publications found

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]

POMT1 Gene-Disease associations (from GenCC):

• muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A1

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Ambry Genetics, Laboratory for Molecular Medicine, Genomics England PanelApp
• myopathy caused by variation in POMT1

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• muscular dystrophy-dystroglycanopathy (congenital with intellectual disability), type B1

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• autosomal recessive limb-girdle muscular dystrophy type 2K

  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
• congenital muscular dystrophy without 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: Uncertain_significance. The variant received 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.277608).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
POMT1	NM_001077365.2	c.26T>C	p.Val9Ala	missense_variant	Exon 2 of 20	ENST00000402686.8	NP_001070833.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
POMT1	ENST00000402686.8	c.26T>C	p.Val9Ala	missense_variant	Exon 2 of 20	1	NM_001077365.2	ENSP00000385797.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461880 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727238

African (AFR) AF: 0.00 AC: 0 AN: 33478

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: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1112006

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2K Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
BayesDel_addAF	Benign	-0.010	T
BayesDel_noAF	Benign	-0.25
CADD	Benign	20
DANN	Benign	0.92
DEOGEN2	Benign	0.31	.;T;.;T
Eigen	Benign	-0.32
Eigen_PC	Benign	-0.31
FATHMM_MKL	Uncertain	0.80	D
LIST_S2	Benign	0.77	T;T;.;T
M_CAP	Uncertain	0.13	D
MetaRNN	Benign	0.28	T;T;T;T
MetaSVM	Benign	-0.53	T
MutationAssessor	Uncertain	2.1	M;M;M;.
PhyloP100		5.3
PrimateAI	Benign	0.23	T
PROVEAN	Benign	-1.6	N;N;N;N
REVEL	Benign	0.22
Sift	Uncertain	0.016	D;D;D;D
Sift4G	Uncertain	0.019	D;D;D;D
Polyphen		0.20	B;B;B;.
Vest4		0.42
MutPred		0.32		Gain of sheet (P = 0.0344);Gain of sheet (P = 0.0344);Gain of sheet (P = 0.0344);Gain of sheet (P = 0.0344);
MVP		0.83
MPC		0.34
ClinPred		0.50	T
GERP RS		5.0
PromoterAI		-0.011	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.13
gMVP		0.64
Mutation Taster		=71/29	polymorphism

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

Other links and lift over

dbSNP: rs1945225387; hg19: chr9-134379631;