18-62161226-G-T

Variant names:

• chr18-62161226-G-T
• rs759600092
• NM_176787.5:c.128C>A

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_176787.5(PIGN):​c.128C>A​(p.Ala43Glu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,456 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A43V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: PIGN NM_176787.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.94
• Publications: 1 publications found

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 Gene-Disease associations (from GenCC):

• multiple congenital anomalies-hypotonia-seizures syndrome 1

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P, Orphanet, ClinGen, PanelApp Australia
• Fryns syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.865

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_176787.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PIGN	NM_176787.5	MANE Select	c.128C>A	p.Ala43Glu	missense	Exon 4 of 31	NP_789744.1
	PIGN	NM_001438896.1		c.128C>A	p.Ala43Glu	missense	Exon 4 of 32	NP_001425825.1
	PIGN	NM_012327.6		c.128C>A	p.Ala43Glu	missense	Exon 3 of 30	NP_036459.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PIGN	ENST00000640252.2	TSL:1 MANE Select	c.128C>A	p.Ala43Glu	missense	Exon 4 of 31	ENSP00000492233.1
	PIGN	ENST00000400334.7	TSL:1	c.128C>A	p.Ala43Glu	missense	Exon 3 of 30	ENSP00000383188.2
	PIGN	ENST00000638424.1	TSL:5	n.128C>A		non_coding_transcript_exon	Exon 2 of 29	ENSP00000491963.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461456 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 727016

African (AFR) AF: 0.00 AC: 0 AN: 33480

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

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26128

East Asian (EAS) AF: 0.00 AC: 0 AN: 39684

South Asian (SAS) AF: 0.00 AC: 0 AN: 86248

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53398

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

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111666

Other (OTH) AF: 0.00 AC: 0 AN: 60364

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Jun 16, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.128C>A (p.A43E) alteration is located in exon 4 (coding exon 1) of the PIGN gene. This alteration results from a C to A substitution at nucleotide position 128, causing the alanine (A) at amino acid position 43 to be replaced by a glutamic acid (E). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.32
CADD	Pathogenic	30
DANN	Uncertain	0.99
DEOGEN2	Benign	0.36	T
Eigen	Pathogenic	0.99
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Uncertain	0.12	D
MetaRNN	Pathogenic	0.87	D
MetaSVM	Uncertain	0.0086	D
MutationAssessor	Pathogenic	3.5	H
PhyloP100		9.9
PrimateAI	Uncertain	0.61	T
PROVEAN	Pathogenic	-4.6	D
REVEL	Uncertain	0.61
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.86
MutPred		0.64		Gain of solvent accessibility (P = 0.0097)
MVP		0.98
MPC		0.20
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.83
gMVP		0.92
Mutation Taster		=12/88	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs759600092; hg19: chr18-59828459; COSMIC: COSV62948506; COSMIC: COSV62948506;