9-131504226-G-C

Variant names:

• chr9-131504226-G-C
• rs975217678
• NM_001077365.2:c.8G>C

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_Strong

The NM_001077365.2(POMT1):​c.8G>C​(p.Gly3Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000684 in 1,461,850 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G3E) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000068 (0 hom.)
• Consequence: POMT1 NM_001077365.2 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.189
• 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: Likely_benign. The variant received -4 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.049800575).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
POMT1	NM_001077365.2	c.8G>C	p.Gly3Ala	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.8G>C	p.Gly3Ala	missense_variant	Exon 2 of 20	1	NM_001077365.2	ENSP00000385797.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000684 AC: 10 AN: 1461850 Hom.: 0 Cov.: 31 AF XY: 0.00000963 AC XY: 7 AN XY: 727224

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

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.000252 AC: 10 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: 0.00 AC: 0 AN: 1111988

Other (OTH) AF: 0.00 AC: 0 AN: 60390

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.10
BayesDel_addAF	Benign	-0.038	T
BayesDel_noAF	Benign	-0.29
CADD	Benign	14
DANN	Benign	0.92
DEOGEN2	Benign	0.21	.;T;.;T
Eigen	Benign	-0.89
Eigen_PC	Benign	-0.84
FATHMM_MKL	Benign	0.17	N
LIST_S2	Benign	0.60	T;T;.;T
M_CAP	Benign	0.015	T
MetaRNN	Benign	0.050	T;T;T;T
MetaSVM	Benign	-0.80	T
MutationAssessor	Benign	1.4	L;L;L;.
PhyloP100		0.19
PrimateAI	Benign	0.28	T
PROVEAN	Benign	-0.37	N;N;N;N
REVEL	Benign	0.16
Sift	Benign	0.096	T;T;T;T
Sift4G	Benign	0.12	T;T;T;T
Polyphen		0.013	B;B;B;.
Vest4		0.30
MutPred		0.29		Loss of disorder (P = 0.0665);Loss of disorder (P = 0.0665);Loss of disorder (P = 0.0665);Loss of disorder (P = 0.0665);
MVP		0.58
MPC		0.38
ClinPred		0.024	T
GERP RS		0.58
PromoterAI		0.014	Neutral
Varity_R		0.065
gMVP		0.57
Mutation Taster		=99/1	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: rs975217678; hg19: chr9-134379613;