20-45420577-A-AC

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_015937.6(PIGT):​c.918dup​(p.Val307ArgfsTer13) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000694 in 1,613,644 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000072 ( 0 hom. )

Consequence

PIGT
NM_015937.6 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:3O:1

Conservation

PhyloP100: -1.07
Variant links:
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]

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 20-45420577-A-AC is Pathogenic according to our data. Variant chr20-45420577-A-AC is described in ClinVar as [Pathogenic]. Clinvar id is 503770.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE Protein UniProt
PIGTNM_015937.6 linkuse as main transcriptc.918dup p.Val307ArgfsTer13 frameshift_variant 8/12 ENST00000279036.12 NP_057021.2

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Protein Appris UniProt
PIGTENST00000279036.12 linkuse as main transcriptc.918dup p.Val307ArgfsTer13 frameshift_variant 8/121 NM_015937.6 ENSP00000279036 P1Q969N2-1

Frequencies

GnomAD3 genomes
AF:
0.0000461
AC:
7
AN:
151776
Hom.:
0
Cov.:
32
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:
0.000103
Gnomad OTH
AF:
0.00
GnomAD3 exomes
AF:
0.0000358
AC:
9
AN:
251484
Hom.:
0
AF XY:
0.0000294
AC XY:
4
AN XY:
135912
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad SAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000791
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000718
AC:
105
AN:
1461868
Hom.:
0
Cov.:
32
AF XY:
0.0000605
AC XY:
44
AN XY:
727236
show subpopulations
Gnomad4 AFR exome
AF:
0.00
Gnomad4 AMR exome
AF:
0.00
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.00
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.0000899
Gnomad4 OTH exome
AF:
0.0000828
GnomAD4 genome
AF:
0.0000461
AC:
7
AN:
151776
Hom.:
0
Cov.:
32
AF XY:
0.0000540
AC XY:
4
AN XY:
74112
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:
0.000103
Gnomad4 OTH
AF:
0.00
Alfa
AF:
0.0000583
Hom.:
0
Bravo
AF:
0.0000227
EpiCase
AF:
0.0000545
EpiControl
AF:
0.0000593

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:3Other:1
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Inborn genetic diseases Pathogenic:1
Pathogenic, criteria provided, single submitterclinical testingAmbry GeneticsApr 18, 2024The c.918dupC (p.V307Rfs*13) alteration, located in exon 8 (coding exon 8) of the PIGT gene, consists of a duplication of C at position 918, causing a translational frameshift with a predicted alternate stop codon after 13 amino acids. This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. Based on data from gnomAD, the CC allele has an overall frequency of 0.004% (11/282816) total alleles studied. The highest observed frequency was 0.009% (11/129174) of European (non-Finnish) alleles. This variant has been identified in conjunction with other PIGT variants in multiple individuals with features consistent with PIGT-related glycosylphosphatidylinositol deficiency; in at least one instance, the variants were identified in trans (Bayat, 2021; Ambry internal data). Based on the available evidence, this alteration is classified as pathogenic. -
Multiple congenital anomalies-hypotonia-seizures syndrome 3 Pathogenic:1
Pathogenic, no assertion criteria providedliterature onlyOMIMMar 12, 2019- -
not provided Pathogenic:1
Pathogenic, criteria provided, single submitterclinical testingGeneDxDec 03, 2023Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 34046058, 33620284, 25943031) -
PIGT-related disorder Other:1
not provided, no classification providedphenotyping onlyGenomeConnect, ClinGen-GenomeConnect assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. GenomeConnect staff make no attempt to reinterpret the clinical significance of the variant. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.080
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.

Other links and lift over

dbSNP: rs751861982; hg19: chr20-44049217; API