18-62147030-T-C

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_176787.5(PIGN):c.746A>G(p.Tyr249Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000745 in 1,611,812 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000062 ( 0 hom. )

Consequence

PIGN
NM_176787.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 4.52

Variant links:

Genes affected

PIGN (HGNC:8967): (phosphatidylinositol glycan anchor biosynthesis class N) This gene encodes a protein that is involved in glycosylphosphatidylinositol (GPI)-anchor biosynthesis. The GPI-anchor is a glycolipid found on many blood cells and serves to anchor proteins to the cell surface. This protein is expressed in the endoplasmic reticulum and transfers phosphoethanolamine (EtNP) to the first mannose of the GPI anchor. Two alternatively spliced variants, which encode an identical isoform, have been reported. [provided by RefSeq, Jul 2008]

PIGN links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PIGN	NM_176787.5 link	c.746A>G	p.Tyr249Cys	missense_variant	Exon 9 of 31	ENST00000640252.2	NP_789744.1	O95427A0A024R2C3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
PIGN	ENST00000640252.2 link	c.746A>G	p.Tyr249Cys	missense_variant	Exon 9 of 31	1	NM_176787.5	ENSP00000492233.1	O95427
PIGN	ENST00000400334.7 link	c.746A>G	p.Tyr249Cys	missense_variant	Exon 8 of 30	1		ENSP00000383188.2	O95427
PIGN	ENST00000638424.1 link	n.746A>G		non_coding_transcript_exon_variant	Exon 7 of 29	5		ENSP00000491963.1	A0A1W2PQZ1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152216

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000807

AC:

AN:

247744

Hom.:

AF XY:

0.00000744

AC XY:

AN XY:

134436

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000559

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000892

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000617

AC:

AN:

1459478

Hom.:

Cov.:

AF XY:

0.00000689

AC XY:

AN XY:

726112

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000253

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000630

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152334

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74494

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ExAC

AF:

0.00000828

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Multiple congenital anomalies-hypotonia-seizures syndrome 1

Uncertain:2

Oct 06, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces tyrosine with cysteine at codon 249 of the PIGN protein (p.Tyr249Cys). The tyrosine residue is moderately conserved and there is a large physicochemical difference between tyrosine and cysteine. This variant is present in population databases (rs199555972, ExAC 0.002%). This variant has not been reported in the literature in individuals affected with PIGN-related conditions. ClinVar contains an entry for this variant (Variation ID: 581394). 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. 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. -

Jun 14, 2021

Johns Hopkins Genomics, Johns Hopkins University

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

PIGN c.746A>G (rs199555972) is rare (<0.1%) in a large population dataset (gnomAD: 2/247744 total alleles; 0.0008%; no homozygotes) and has been reported in ClinVar (Variation ID:581394). This variant has been reported in an individual with seizures and digital anomalies, however this report has not been peer-reviewed. Three bioinformatic tools queried predict that this substitution would be damaging and the tyrosine residue at this position is evolutionarily conserved across most of the species assessed. We consider the clinical significance of PIGN c.746A>G to be uncertain at this time. -

not specified

Uncertain:1

Mar 26, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: PIGN c.746A>G (p.Tyr249Cys) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8.1e-06 in 247744 control chromosomes. c.746A>G has been reported in the literature in individuals affected with features of Multiple Congenital Anomalies-Hypotonia Syndrome 1 (e.g. Bayat_2022, Sidpra_2024), as well as in homozygous prenatal cases with Hydrocephalus (Gabriel_2022). These data indicate that the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 35179230, 34958143, 38456468). ClinVar contains an entry for this variant (Variation ID: 581394). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

not provided

Uncertain:1

May 01, 2018

CeGaT Center for Human Genetics Tuebingen

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.16

BayesDel_addAF

Uncertain

0.033

BayesDel_noAF

Uncertain

-0.020

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Benign

0.35

T;.;T;T;T;.;.;.;.;.;T;.;.;T;.;T;.;.;.;.;.;.;.;.;.

Eigen

Pathogenic

0.74

Eigen_PC

Pathogenic

0.70

FATHMM_MKL

Uncertain

0.95

LIST_S2

Pathogenic

0.99

.;.;.;.;.;.;D;.;D;D;.;D;D;.;D;D;D;D;.;.;D;D;D;D;D

M_CAP

Benign

0.056

MetaRNN

Uncertain

0.68

D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D

MetaSVM

Benign

-0.51

MutationAssessor

Pathogenic

3.2

M;.;M;M;M;.;.;.;.;.;M;.;.;M;.;M;.;.;.;.;.;.;.;.;.

PrimateAI

Uncertain

0.51

PROVEAN

Pathogenic

-8.2

.;.;.;D;.;.;.;.;.;.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.

REVEL

Uncertain

0.34

Sift

Pathogenic

0.0

.;.;.;D;.;.;.;.;.;.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.

Sift4G

Pathogenic

0.0010

.;.;.;D;.;.;.;.;.;.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.

Polyphen

1.0

D;.;D;D;D;.;.;.;.;.;D;.;.;D;.;D;.;.;.;.;.;.;.;.;.

Vest4

0.69, 0.69

MVP

0.77

MPC

0.21

ClinPred

1.0

GERP RS

5.7

Varity_R

0.94

gMVP

0.78

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over