18-62106985-C-T

Variant names:

• chr18-62106985-C-T
• rs376355678
• NM_176787.5:c.1674+1G>A

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_176787.5(PIGN):​c.1674+1G>A variant causes a splice donor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: PIGN NM_176787.5 splice_donor, intron
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 6.40
• Publications: 3 publications found

Genes affected

PIGN (HGNC:8967): (phosphatidylinositol glycan anchor biosynthesis class N) This gene encodes a protein that is involved in glycosylphosphatidylinositol (GPI)-anchor biosynthesis. The GPI-anchor is a glycolipid found on many blood cells and serves to anchor proteins to the cell surface. This protein is expressed in the endoplasmic reticulum and transfers phosphoethanolamine (EtNP) to the first mannose of the GPI anchor. Two alternatively spliced variants, which encode an identical isoform, have been reported. [provided by RefSeq, Jul 2008]

PIGN Gene-Disease associations (from GenCC):

• multiple congenital anomalies-hypotonia-seizures syndrome 1

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: ClinGen, G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae), Orphanet
• Fryns syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 18-62106985-C-T is Pathogenic according to our data. Variant chr18-62106985-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 425152.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_176787.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PIGN	NM_176787.5	MANE Select	c.1674+1G>A		splice_donor intron	N/A	NP_789744.1	O95427
	PIGN	NM_001438896.1		c.1674+1G>A		splice_donor intron	N/A	NP_001425825.1
	PIGN	NM_012327.6		c.1674+1G>A		splice_donor intron	N/A	NP_036459.1	O95427

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PIGN	ENST00000640252.2	TSL:1 MANE Select	c.1674+1G>A		splice_donor intron	N/A	ENSP00000492233.1	O95427
	PIGN	ENST00000400334.7	TSL:1	c.1674+1G>A		splice_donor intron	N/A	ENSP00000383188.2	O95427
	PIGN	ENST00000638424.1	TSL:5	n.1674+1G>A		splice_donor intron	N/A	ENSP00000491963.1	A0A1W2PQZ1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1418632 Hom.: 0 Cov.: 28 AF XY: 0.00 AC XY: 0 AN XY: 702782

African (AFR) AF: 0.00 AC: 0 AN: 32220

American (AMR) AF: 0.00 AC: 0 AN: 39786

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25340

East Asian (EAS) AF: 0.00 AC: 0 AN: 37642

South Asian (SAS) AF: 0.00 AC: 0 AN: 80602

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51276

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5718

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1087076

Other (OTH) AF: 0.00 AC: 0 AN: 58972

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Likely pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.41
CADD	Pathogenic	28
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	1.0	D
PhyloP100		6.4
Mutation Taster		=2/98	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.93		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.93		Position offset: 1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs376355678;

hg19: chr18-59774218;