rs1554673856

Positions:

• chr9-35095510-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_032634.4(PIGO):​c.56C>T​(p.Ala19Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A19S) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: PIGO NM_032634.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.93

Genes affected

PIGO (HGNC:23215): (phosphatidylinositol glycan anchor biosynthesis class O) This gene encodes a protein that is involved in glycosylphosphatidylinositol (GPI)-anchor biosynthesis. The GPI-anchor is a glycolipid which contains three mannose molecules in its core backbone. The GPI-anchor is found on many blood cells and serves to anchor proteins to the cell surface. This protein is involved in the transfer of ethanolaminephosphate (EtNP) to the third mannose in GPI. At least three alternatively spliced transcripts encoding two distinct isoforms have been found for this gene. [provided by RefSeq, Jan 2011]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.17721328).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PIGO	NM_032634.4	c.56C>T	p.Ala19Val	missense_variant	2/11	ENST00000378617.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PIGO	ENST00000378617.4	c.56C>T	p.Ala19Val	missense_variant	2/11	1	NM_032634.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hyperphosphatasia with intellectual disability syndrome 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 27, 2020

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 tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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. This variant has not been reported in the literature in individuals with PIGO-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces alanine with valine at codon 19 of the PIGO protein (p.Ala19Val). The alanine residue is moderately conserved and there is a small physicochemical difference between alanine and valine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.074	T
BayesDel_noAF	Benign	-0.34
CADD	Benign	17
DANN	Uncertain	0.98
DEOGEN2	Benign	0.082	.;.;T
Eigen	Benign	-0.49
Eigen_PC	Benign	-0.35
FATHMM_MKL	Benign	0.69	D
LIST_S2	Benign	0.84	.;T;D
M_CAP	Benign	0.0083	T
MetaRNN	Benign	0.18	T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.0	L;L;L
MutationTaster	Benign	1.0	N;N;N;N
PrimateAI	Benign	0.40	T
PROVEAN	Benign	-0.43	N;N;N
REVEL	Benign	0.087
Sift	Benign	0.20	T;T;T
Sift4G	Benign	0.29	T;T;T
Polyphen		0.0070	B;B;B
Vest4		0.26
MutPred		0.34		Gain of helix (P = 0.0199);Gain of helix (P = 0.0199);Gain of helix (P = 0.0199);
MVP		0.53
MPC		0.15
ClinPred		0.42	T
GERP RS		4.6
Varity_R		0.11
gMVP		0.60

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

LitVar

Other links and lift over

dbSNP: rs1554673856; hg19: chr9-35095507;