chr15-55355385-T-C

Position:

• chr15-55355385-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_004855.5(PIGB):​c.1618T>C​(p.Tyr540His) 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: 33)
• Consequence: PIGB NM_004855.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.58

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]

CCPG1 (HGNC:24227): (cell cycle progression 1) Involved in positive regulation of cell cycle and positive regulation of cell population proliferation. Predicted to be integral component of membrane. Predicted to be active in membrane. [provided by Alliance of Genome Resources, Apr 2022]

DNAAF4-CCPG1 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.862

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PIGB	NM_004855.5	c.1618T>C	p.Tyr540His	missense_variant	12/12	ENST00000164305.10	NP_004846.4
CCPG1	NM_001204450.2	c.*835A>G		3_prime_UTR_variant	9/9	ENST00000442196.8	NP_001191379.1
DNAAF4-CCPG1	NR_037923.1	n.4676A>G		non_coding_transcript_exon_variant	16/16

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PIGB	ENST00000164305.10	c.1618T>C	p.Tyr540His	missense_variant	12/12	1	NM_004855.5	ENSP00000164305	P2
CCPG1	ENST00000442196.8	c.*835A>G		3_prime_UTR_variant	9/9	2	NM_001204450.2	ENSP00000403400	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 33

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

Labcorp Genetics (formerly Invitae), Labcorp

Jul 29, 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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. This variant has not been reported in the literature in individuals affected with PIGB-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces tyrosine, which is neutral and polar, with histidine, which is basic and polar, at codon 540 of the PIGB protein (p.Tyr540His). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.43
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.16
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.14	T;T
Eigen	Uncertain	0.67
Eigen_PC	Pathogenic	0.69
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Benign	0.85	T;T
M_CAP	Benign	0.022	T
MetaRNN	Pathogenic	0.86	D;D
MetaSVM	Benign	-0.37	T
MutationAssessor	Pathogenic	3.2	M;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Uncertain	0.64	T
PROVEAN	Uncertain	-3.1	D;.
REVEL	Uncertain	0.45
Sift	Benign	0.042	D;.
Sift4G	Uncertain	0.044	D;D
Polyphen		0.94	P;.
Vest4		0.86
MutPred		0.70		Gain of disorder (P = 0.0321);.;
MVP		0.71
MPC		0.19
ClinPred		0.97	D
GERP RS		6.1
Varity_R		0.35
gMVP		0.86

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs919526409; hg19: chr15-55647583;