1-160030739-T-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_145167.3(PIGM):c.1001A>C(p.Gln334Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000041 in 1,461,882 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: 0.0000041 (0 hom.)
• Consequence: PIGM NM_145167.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.62

Genes affected

PIGM (HGNC:18858): (phosphatidylinositol glycan anchor biosynthesis class M) This gene encodes a transmembrane protein that is located in the endoplasmic reticulum and is involved in GPI-anchor biosynthesis. The glycosylphosphatidylinositol (GPI)-anchor is a glycolipid which contains three mannose molecules in its core backbone. The GPI-anchor is found on many blood cells and serves to anchor proteins to the cell surface. This gene encodes a mannosyltransferase, GPI-MT-I, that transfers the first mannose to GPI on the lumenal side of the endoplasmic reticulum. [provided by RefSeq, Jul 2008]

KCNJ10 (HGNC:6256): (potassium inwardly rectifying channel subfamily J member 10) This gene encodes a member of the inward rectifier-type potassium channel family, characterized by having a greater tendency to allow potassium to flow into, rather than out of, a cell. The encoded protein may form a heterodimer with another potassium channel protein and may be responsible for the potassium buffering action of glial cells in the brain. Mutations in this gene have been associated with seizure susceptibility of common idiopathic generalized epilepsy syndromes. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.969

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PIGM	NM_145167.3	c.1001A>C	p.Gln334Pro	missense_variant	1/1	ENST00000368090.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PIGM	ENST00000368090.5	c.1001A>C	p.Gln334Pro	missense_variant	1/1		NM_145167.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000410 AC: 6 AN: 1461882 Hom.: 0 Cov.: 32 AF XY: 0.00000550 AC XY: 4 AN XY: 727242

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: 0.00000540

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.0000113

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hypercoagulability syndrome due to glycosylphosphatidylinositol deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jun 30, 2022

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. 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 disruptive. ClinVar contains an entry for this variant (Variation ID: 1055901). This variant has not been reported in the literature in individuals affected with PIGM-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glutamine, which is neutral and polar, with proline, which is neutral and non-polar, at codon 334 of the PIGM protein (p.Gln334Pro). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.85
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.29
Cadd	Pathogenic	30
Dann	Uncertain	0.99
DEOGEN2	Benign	0.39	T
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.87	D
M_CAP	Uncertain	0.25	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Uncertain	0.067	D
MutationAssessor	Pathogenic	3.7	H
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.65	T
PROVEAN	Pathogenic	-5.7	D
REVEL	Pathogenic	0.65
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.94
MutPred		0.86		Gain of glycosylation at Q334 (P = 0.0916);
MVP		0.86
MPC		1.2
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.98
gMVP		0.96

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: rs1648302230; hg19: chr1-160000529;