20-45418853-G-A

Position:

• chr20-45418853-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_015937.6(PIGT):​c.367G>A​(p.Val123Met) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,662 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V123L) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: PIGT NM_015937.6 missense, splice_region
• Scores: Splicing: ADA: 0.9911
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.73

Genes affected

PIGT (HGNC:14938): (phosphatidylinositol glycan anchor biosynthesis class T) 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 an essential component of the multisubunit enzyme, GPI transamidase. GPI transamidase mediates GPI anchoring in the endoplasmic reticulum, by catalyzing the transfer of fully assembled GPI units to proteins. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, May 2012]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PIGT	NM_015937.6	c.367G>A	p.Val123Met	missense_variant, splice_region_variant	3/12	ENST00000279036.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PIGT	ENST00000279036.12	c.367G>A	p.Val123Met	missense_variant, splice_region_variant	3/12	1	NM_015937.6	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251486 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135918

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461662 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 727138

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: 0.00000360

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.29
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.050
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Benign	0.22	T;.;.;.;.;.
Eigen	Pathogenic	0.81
Eigen_PC	Pathogenic	0.82
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.97	D;D;D;D;T;D
M_CAP	Benign	0.026	D
MetaRNN	Pathogenic	0.80	D;D;D;D;D;D
MetaSVM	Benign	-0.63	T
MutationTaster	Benign	1.0	D;D;D;D;D;D
PrimateAI	Uncertain	0.72	T
PROVEAN	Uncertain	-2.5	N;N;.;.;.;.
REVEL	Uncertain	0.32
Sift	Uncertain	0.0010	D;D;.;.;.;.
Sift4G	Uncertain	0.0030	D;D;.;.;.;.
Polyphen		0.86	P;.;.;.;.;.
Vest4		0.78
MutPred		0.80		Gain of disorder (P = 0.0953);Gain of disorder (P = 0.0953);Gain of disorder (P = 0.0953);Gain of disorder (P = 0.0953);.;Gain of disorder (P = 0.0953);
MVP		0.47
MPC		0.52
ClinPred		0.96	D
GERP RS		5.8
Varity_R		0.35
gMVP		0.69

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.99
dbscSNV1_RF	Pathogenic	0.82
SpliceAI score (max)		0.070		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: rs141420243; hg19: chr20-44047493;