rs1057518632

Variant names:

• chr9-35092535-A-C
• rs1057518632
• NM_032634.4:c.1352T>G

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM2 PP3_Strong PP5

The NM_032634.4(PIGO):​c.1352T>G​(p.Met451Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,836 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M451V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: PIGO NM_032634.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 8.43
• Publications: 1 publications found

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]

PIGO Gene-Disease associations (from GenCC):

• complex neurodevelopmental disorder

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• hyperphosphatasia with intellectual disability syndrome 2

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Illumina, Labcorp Genetics (formerly Invitae), PanelApp Australia
• hyperphosphatasia-intellectual disability syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.968
• PP5: Variant 9-35092535-A-C is Pathogenic according to our data. Variant chr9-35092535-A-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 373818.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PIGO	NM_032634.4	c.1352T>G	p.Met451Arg	missense_variant	Exon 7 of 11	ENST00000378617.4	NP_116023.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PIGO	ENST00000378617.4	c.1352T>G	p.Met451Arg	missense_variant	Exon 7 of 11	1	NM_032634.4	ENSP00000367880.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461836 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727208

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000360 AC: 4 AN: 1111974

Other (OTH) AF: 0.00 AC: 0 AN: 60384

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1

Dec 16, 2016

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The M451R variant in the PIGO gene has not been reported previously as a pathogenic variant, nor as a benign variant, to our knowledge. The M451R variant was not observed in approximately 6500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The M451R variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved across species, and in silico analysis predicts this variant is probably damaging to the protein structure/function. As an alternate mechanism, multiple in silico algorithms predict that this sequence change might create a cryptic splice acceptor site in exon 7 which may supplant the natural acceptor site. However, in the absence of RNA/functional studies, the actual effect of this sequence change in this individual is unknown. The M451R variant is a strong candidate for a pathogenic variant, however the possibility it may be a rare benign variant cannot be excluded. -

Hyperphosphatasia with intellectual disability syndrome 2 Uncertain:1

Jul 12, 2018

HudsonAlpha Institute for Biotechnology, HudsonAlpha Institute for Biotechnology

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: research

ACMG codes: PM2, PP3, PP5 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.89
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.56	D
Eigen	Pathogenic	0.87
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Benign	0.76	T
M_CAP	Uncertain	0.18	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Uncertain	0.17	D
MutationAssessor	Pathogenic	3.1	M
PhyloP100		8.4
PrimateAI	Uncertain	0.64	T
PROVEAN	Pathogenic	-5.1	D
REVEL	Pathogenic	0.84
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0030	D
Polyphen		1.0	D
Vest4		0.96
MutPred		0.80		Gain of methylation at M451 (P = 0.0039);
MVP		0.94
MPC		0.81
ClinPred		1.0	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.7
Varity_R		0.91
gMVP		0.96
Mutation Taster		=43/57	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
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

Other links and lift over

dbSNP: rs1057518632; hg19: chr9-35092532;