4-505728-C-T

Variant names:

• chr4-505728-C-T
• rs370385328
• NM_001127178.3:c.371C>T

Variant summary

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

The NM_001345988.2(PIGG):​c.-517C>T variant causes a 5 prime UTR premature start codon gain change. The variant allele was found at a frequency of 0.0000775 in 1,612,300 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 Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000059 (0 hom., cov: 29)
  • Exomes 𝑓: 0.000079 (0 hom.)
• Consequence: PIGG NM_001345988.2 5_prime_UTR_premature_start_codon_gain
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.14

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 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.878

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PIGG	NM_001127178.3	c.371C>T	p.Thr124Met	missense_variant	Exon 3 of 13	ENST00000453061.7	NP_001120650.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PIGG	ENST00000453061.7	c.371C>T	p.Thr124Met	missense_variant	Exon 3 of 13	1	NM_001127178.3	ENSP00000415203.2

Frequencies

GnomAD3 genomes AF: 0.0000661 AC: 10 AN: 151262 Hom.: 0 Cov.: 29

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000132

Gnomad ASJ AF: 0.000577

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00318

Gnomad NFE AF: 0.0000736

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000955 AC: 24 AN: 251354 Hom.: 0 AF XY: 0.000140 AC XY: 19 AN XY: 135864

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00149

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000792

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000794 AC: 116 AN: 1460922 Hom.: 0 Cov.: 31 AF XY: 0.0000771 AC XY: 56 AN XY: 726752

Gnomad4 AFR exome AF: 0.0000897

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00123

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000585

Gnomad4 OTH exome AF: 0.000199

GnomAD4 genome AF: 0.0000595 AC: 9 AN: 151378 Hom.: 0 Cov.: 29 AF XY: 0.0000271 AC XY: 2 AN XY: 73886

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.000132

Gnomad4 ASJ AF: 0.000577

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000736

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000152 Hom.: 0

Bravo AF: 0.0000642

ESP6500AA AF: 0.000227 AC: 1

ESP6500EA AF: 0.00 AC: 0

ExAC AF: 0.0000659 AC: 8

Asia WGS AF: 0.000289 AC: 1 AN: 3478

EpiCase AF: 0.000109

EpiControl AF: 0.000119

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Intellectual disability, autosomal recessive 53 Uncertain:1

Aug 13, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 124 of the PIGG protein (p.Thr124Met). This variant is present in population databases (rs370385328, gnomAD 0.1%). This missense change has been observed in individual(s) with congenital disorder of glycosylation (PMID: 34113002). ClinVar contains an entry for this variant (Variation ID: 476347). 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. 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	0.26
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.48
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Benign	0.24	.;T;T;.;.
Eigen	Pathogenic	0.87
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.99	D;D;D;D;D
M_CAP	Uncertain	0.27	D
MetaRNN	Pathogenic	0.88	D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.8	H;H;.;.;.
PrimateAI	Uncertain	0.78	T
PROVEAN	Pathogenic	-5.0	D;D;D;D;D
REVEL	Pathogenic	0.76
Sift	Uncertain	0.0010	D;D;D;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D;D
Polyphen		1.0	D;D;.;D;D
Vest4		0.96
MVP		1.0
MPC		0.71
ClinPred		0.97	D
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.60
gMVP		0.97

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: rs370385328; hg19: chr4-499517;