1-172442090-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_153747.2(PIGC):c.533C>T(p.Ser178Phe) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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)
• Consequence: PIGC NM_153747.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.38

Genes affected

PIGC (HGNC:8960): (phosphatidylinositol glycan anchor biosynthesis class C) This gene encodes an endoplasmic reticulum associated protein that is involved in glycosylphosphatidylinositol (GPI) lipid anchor biosynthesis. The GPI lipid anchor is a glycolipid found on many blood cells and serves to anchor proteins to the cell surface. The encoded protein is one subunit of the GPI N-acetylglucosaminyl (GlcNAc) transferase that transfers GlcNAc to phosphatidylinositol (PI) on the cytoplasmic side of the endoplasmic reticulum. Two alternatively spliced transcripts that encode the same protein have been found for this gene. A pseudogene on chromosome 11 has also been characterized. [provided by RefSeq, Jul 2008]

C1orf105 (HGNC:29591): (chromosome 1 open reading frame 105)

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a chain Phosphatidylinositol N-acetylglucosaminyltransferase subunit C (size 296) in uniprot entity PIGC_HUMAN there are 6 pathogenic changes around while only 2 benign (75%) in NM_153747.2
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.983

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PIGC	NM_153747.2	c.533C>T	p.Ser178Phe	missense_variant	2/2	ENST00000344529.5
C1orf105	NM_139240.4	c.22-2983G>A		intron_variant		ENST00000367727.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PIGC	ENST00000344529.5	c.533C>T	p.Ser178Phe	missense_variant	2/2	1	NM_153747.2	P1
C1orf105	ENST00000367727.9	c.22-2983G>A		intron_variant		1	NM_139240.4	P1
PIGC	ENST00000484368.1	n.96+1898C>T		intron_variant, non_coding_transcript_variant		1
PIGC	ENST00000367728.1	c.533C>T	p.Ser178Phe	missense_variant	1/1			P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 39

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 04, 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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt PIGC protein function. This variant has not been reported in the literature in individuals affected with PIGC-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces serine, which is neutral and polar, with phenylalanine, which is neutral and non-polar, at codon 178 of the PIGC protein (p.Ser178Phe). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.33
Cadd	Pathogenic	30
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.49	T;T
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.91
FATHMM_MKL	Pathogenic	0.98	D
M_CAP	Benign	0.085	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Uncertain	0.20	D
MutationAssessor	Pathogenic	3.4	M;M
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-5.7	D;D
REVEL	Pathogenic	0.80
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.97
MutPred		0.93		Gain of helix (P = 0.062);Gain of helix (P = 0.062);
MVP		0.91
MPC		0.61
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.98
gMVP		0.98

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr1-172411230;