9-131504241-C-T

Position:

• chr9-131504241-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_001353198.2(POMT1):​c.-449C>T variant causes a 5 prime UTR premature start codon gain change. The variant allele was found at a frequency of 0.00000684 in 1,461,876 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 Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000068 (0 hom.)
• Consequence: POMT1 NM_001353198.2 5_prime_UTR_premature_start_codon_gain
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.90

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 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.867

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
POMT1	NM_001077365.2	c.23C>T	p.Pro8Leu	missense_variant	2/20	ENST00000402686.8	NP_001070833.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
POMT1	ENST00000402686.8	c.23C>T	p.Pro8Leu	missense_variant	2/20	1	NM_001077365.2	ENSP00000385797.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000684 AC: 10 AN: 1461876 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 727238

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000899

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

TwinsUK AF: 0.000539 AC: 2

ALSPAC AF: 0.00 AC: 0

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

Jan 28, 2022

This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 8 of the POMT1 protein (p.Pro8Leu). 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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). 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	0.42
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.17
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.73	.;D;.;T
Eigen	Uncertain	0.44
Eigen_PC	Uncertain	0.35
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.95	D;D;.;D
M_CAP	Uncertain	0.19	D
MetaRNN	Pathogenic	0.87	D;D;D;D
MetaSVM	Uncertain	0.77	D
MutationAssessor	Uncertain	2.6	M;M;M;.
PrimateAI	Uncertain	0.51	T
PROVEAN	Pathogenic	-4.4	D;D;D;D
REVEL	Pathogenic	0.67
Sift	Uncertain	0.0040	D;D;D;D
Sift4G	Uncertain	0.013	D;D;D;D
Polyphen		0.96	P;D;P;.
Vest4		0.91
MutPred		0.62		Gain of MoRF binding (P = 0.023);Gain of MoRF binding (P = 0.023);Gain of MoRF binding (P = 0.023);Gain of MoRF binding (P = 0.023);
MVP		0.92
MPC		0.90
ClinPred		0.99	D
GERP RS		5.0
Varity_R		0.35
gMVP		0.80

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: rs760216356; hg19: chr9-134379628; COSMIC: COSV100260997; COSMIC: COSV100260997;