4-521195-G-T

Variant names:

• chr4-521195-G-T
• rs139518242
• NM_001127178.3:c.1254G>T

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_001127178.3(PIGG):​c.1254G>T​(p.Thr418Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,788 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. T418T) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: PIGG NM_001127178.3 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.0960
• Publications: 2 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: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.78).
• BP7: Synonymous conserved (PhyloP=-0.096 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001127178.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PIGG	NM_001127178.3	MANE Select	c.1254G>T	p.Thr418Thr	synonymous	Exon 7 of 13	NP_001120650.1
	PIGG	NM_017733.5		c.1254G>T	p.Thr418Thr	synonymous	Exon 7 of 13	NP_060203.3
	PIGG	NM_001289051.2		c.987G>T	p.Thr329Thr	synonymous	Exon 7 of 13	NP_001275980.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PIGG	ENST00000453061.7	TSL:1 MANE Select	c.1254G>T	p.Thr418Thr	synonymous	Exon 7 of 13	ENSP00000415203.2
	PIGG	ENST00000383028.8	TSL:1	c.855G>T	p.Thr285Thr	synonymous	Exon 5 of 11	ENSP00000372494.4
	PIGG	ENST00000509768.1	TSL:1	c.987G>T	p.Thr329Thr	synonymous	Exon 7 of 8	ENSP00000421550.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251482 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461788 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727204

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: 53420

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

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111912

Other (OTH) AF: 0.00 AC: 0 AN: 60390

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.78
CADD	Benign	1.7
DANN	Benign	0.36
PhyloP100		-0.096
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

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

Other links and lift over

dbSNP: rs139518242; hg19: chr4-514984;