4-499364-C-A

Variant summary

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

The NM_001127178.3(PIGG):c.29C>A(p.Thr10Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000621 in 1,609,704 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. T10T) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000046 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: PIGG NM_001127178.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.993

Genes affected

PIGG (HGNC:25985): (phosphatidylinositol glycan anchor biosynthesis class G (EMM blood group)) This gene encodes an enzyme involved in glycosylphosphatidylinositol-anchor biosynthesis. The encoded protein, which is localized to the endoplasmic reticulum, is involved in transferring ethanoloamine phosphate to mannose 2 of glycosylphosphatidylinositol species H7 to form species H8. Allelic variants of this gene have been associated with intellectual disability, hypotonia, and early-onset seizures. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Sep 2016]

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=0.0766018).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PIGG	NM_001127178.3	c.29C>A	p.Thr10Asn	missense_variant	1/13	ENST00000453061.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PIGG	ENST00000453061.7	c.29C>A	p.Thr10Asn	missense_variant	1/13	1	NM_001127178.3	P4

Frequencies

GnomAD3 genomes AF: 0.0000460 AC: 7 AN: 152208 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000145

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: 0.00

Gnomad OTH AF: 0.000478

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1457496 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 725264

Gnomad4 AFR exome AF: 0.0000896

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 AF: 0.0000460 AC: 7 AN: 152208 Hom.: 0 Cov.: 32 AF XY: 0.0000403 AC XY: 3 AN XY: 74364

Gnomad4 AFR AF: 0.000145

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: 0.00

Gnomad4 OTH AF: 0.000478

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.0000793

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Intellectual disability, autosomal recessive 53 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 19, 2022

This sequence change replaces threonine, which is neutral and polar, with asparagine, which is neutral and polar, at codon 10 of the PIGG protein (p.Thr10Asn). This variant is present in population databases (no rsID available, gnomAD 0.008%). This variant has not been reported in the literature in individuals affected with PIGG-related conditions. 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. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.27
BayesDel_addAF	Benign	-0.40	T
BayesDel_noAF	Benign	-0.63
Cadd	Benign	18
Dann	Benign	0.97
Eigen	Benign	-0.47
Eigen_PC	Benign	-0.35
FATHMM_MKL	Benign	0.095	N
LIST_S2	Benign	0.74	T;T;T
M_CAP	Benign	0.012	T
MetaRNN	Benign	0.077	T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.55	N;N;N
MutationTaster	Benign	1.0	D;D;D;D;D;N;N;N
PrimateAI	Uncertain	0.58	T
PROVEAN	Benign	-0.99	N;N;N
REVEL	Benign	0.026
Sift	Uncertain	0.024	D;D;D
Sift4G	Uncertain	0.060	T;T;T
Polyphen		0.056	B;B;B
Vest4		0.29
MVP		0.17
MPC		0.21
ClinPred		0.23	T
GERP RS		4.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
Varity_R		0.22
gMVP		0.49

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: rs946101156; hg19: chr4-493153;