chr4-523897-G-T

Variant names:

• chr4-523897-G-T
• rs200770933
• NM_001127178.3:c.2053G>T

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_001127178.3(PIGG):​c.2053G>T​(p.Gly685Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000131 in 1,530,546 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G685S) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 7.3e-7 (0 hom.)
• Consequence: PIGG NM_001127178.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.46
• Publications: 6 publications found

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]

PIGG Gene-Disease associations (from GenCC):

• intellectual disability, autosomal recessive 53

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.76

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PIGG	NM_001127178.3	c.2053G>T	p.Gly685Cys	missense_variant	Exon 9 of 13	ENST00000453061.7	NP_001120650.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PIGG	ENST00000453061.7	c.2053G>T	p.Gly685Cys	missense_variant	Exon 9 of 13	1	NM_001127178.3	ENSP00000415203.2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152228 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

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: 0.00

GnomAD2 exomes AF: 0.00000699 AC: 1 AN: 143012 AF XY: 0.00

Gnomad AFR exome AF: 0.000130

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 7.26e-7 AC: 1 AN: 1378318 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 675620

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.0000318 AC: 1 AN: 31398

American (AMR) AF: 0.00 AC: 0 AN: 35154

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 24230

East Asian (EAS) AF: 0.00 AC: 0 AN: 35468

South Asian (SAS) AF: 0.00 AC: 0 AN: 78102

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 47956

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5554

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1063508

Other (OTH) AF: 0.00 AC: 0 AN: 56948

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152228 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74374

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.0000241 AC: 1 AN: 41456

American (AMR) AF: 0.00 AC: 0 AN: 15292

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5188

South Asian (SAS) AF: 0.00 AC: 0 AN: 4836

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10628

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68034

Other (OTH) AF: 0.00 AC: 0 AN: 2094

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.00 Hom.: 2

Bravo AF: 0.00000378

ExAC AF: 0.00000912 AC: 1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.41
BayesDel_addAF	Benign	-0.18	T
BayesDel_noAF	Benign	-0.25
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.17	.;T;T;.
Eigen	Uncertain	0.52
Eigen_PC	Uncertain	0.44
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.94	D;D;D;D
M_CAP	Benign	0.011	T
MetaRNN	Pathogenic	0.76	D;D;D;D
MetaSVM	Benign	-1.1	T
MutationAssessor	Uncertain	2.6	.;M;.;.
PhyloP100		3.5
PrimateAI	Uncertain	0.59	T
PROVEAN	Pathogenic	-5.4	D;D;D;D
REVEL	Benign	0.17
Sift	Uncertain	0.0020	D;D;D;D
Sift4G	Uncertain	0.0080	D;D;D;D
Polyphen		1.0	D;D;.;D
Vest4		0.74
MutPred		0.41		.;Loss of disorder (P = 0.0222);.;.;
MVP		0.46
MPC		0.70
ClinPred		0.97	D
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.69
gMVP		0.65
Mutation Taster		=63/37	polymorphism

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: rs200770933; hg19: chr4-517686;