Genetic Variant NM_004855.5:c.73C>T (chr15-55319323-C-T) – ACMG Classification: Likely_pathogenic (8 pts)

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_StrongPM2PP5_Moderate

The NM_004855.5(PIGB):c.73C>T(p.Gln25*) variant causes a stop gained change involving the alteration of a non-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 Pathogenic (★).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

PIGB
NM_004855.5 stop_gained

Scores

Clinical Significance

Pathogenic criteria provided, single submitter P:1

Conservation

PhyloP100: 1.95

Variant links:

Genes affected

PIGB (HGNC:8959): (phosphatidylinositol glycan anchor biosynthesis class B) This gene encodes a transmembrane protein that is located in the endoplasmic reticulum and is involved in GPI-anchor biosynthesis. The glycosylphosphatidylinositol (GPI) anchor is a glycolipid found on many blood cells and serves to anchor proteins to the cell surface. This gene is thought to encode a member of a family of dolichol-phosphate-mannose (Dol-P-Man) dependent mannosyltransferases. [provided by RefSeq, Jul 2008]

PIGB links:

PIGBOS1 (HGNC:50696): (PIGB opposite strand 1) Involved in regulation of endoplasmic reticulum unfolded protein response. Is integral component of mitochondrial outer membrane. [provided by Alliance of Genome Resources, Apr 2022]

PIGBOS1 links:

RAB27A (HGNC:9766): (RAB27A, member RAS oncogene family) The protein encoded by this gene belongs to the small GTPase superfamily, Rab family. The protein is membrane-bound and may be involved in protein transport and small GTPase mediated signal transduction. Mutations in this gene are associated with Griscelli syndrome type 2. Alternative splicing occurs at this locus and four transcript variants encoding the same protein have been identified. [provided by RefSeq, Jul 2008]

RAB27A links:

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ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 9 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 15-55319323-C-T is Pathogenic according to our data. Variant chr15-55319323-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 2098872.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PIGB	NM_004855.5 link	c.73C>T	p.Gln25*	stop_gained	Exon 1 of 12	ENST00000164305.10	NP_004846.4	Q92521
PIGBOS1	NM_001308421.2 link	c.-535G>A		upstream_gene_variant		ENST00000436697.3	NP_001295350.1	A0A0B4J2F0

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
PIGB	ENST00000164305.10 link	c.73C>T	p.Gln25*	stop_gained	Exon 1 of 12	1	NM_004855.5	ENSP00000164305.5	Q92521
PIGB	ENST00000566999.5 link	c.73C>T	p.Gln25*	stop_gained	Exon 1 of 6	3		ENSP00000456531.1	H3BS45
PIGBOS1	ENST00000436697.3 link	c.-535G>A		upstream_gene_variant		2	NM_001308421.2	ENSP00000484893.1	A0A0B4J2F0

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

1441920

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

715076

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:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not provided

Pathogenic:1

Sep 19, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Gln25*) in the PIGB gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in PIGB are known to be pathogenic (PMID: 31256876, 34400385). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with clinical features of PIGB-related conditions (PMID: 31175295). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.41

BayesDel_noAF

Pathogenic

0.35

CADD

Pathogenic

DANN

Uncertain

1.0

Eigen

Uncertain

0.32

Eigen_PC

Benign

0.031

FATHMM_MKL

Benign

0.10

Vest4

0.070

GERP RS

5.0

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.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over