17-36537747-C-T

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 7P and 1B. PVS1_StrongPM2PP5BS1_Supporting

The NM_001346754.2(PIGW):c.646C>T(p.Arg216*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000756 in 1,613,924 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 Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000053 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000078 ( 0 hom. )

Consequence

PIGW
NM_001346754.2 stop_gained

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3U:2

Conservation

PhyloP100: 0.814

Publications

5 publications found

Variant links:

Genes affected

PIGW (HGNC:23213): (phosphatidylinositol glycan anchor biosynthesis class W) The protein encoded by this gene is an inositol acyltransferase that acylates the inositol ring of phosphatidylinositol. This occurs in the endoplasmic reticulum and is a step in the biosynthesis of glycosylphosphatidylinositol (GPI), which anchors many cell surface proteins to the membrane. Defects in this gene are a cause of the age-dependent epileptic encephalopathy West syndrome as well as a syndrome exhibiting hyperphosphatasia and cognitive disability (HPMRS5). [provided by RefSeq, Jul 2017]

PIGW links:

MYO19 (HGNC:26234): (myosin XIX) Enables actin binding activity. Involved in regulation of cytokinesis and regulation of mitochondrial fission. Acts upstream of or within mitochondrion migration along actin filament. Located in cytosol and mitochondrial outer membrane. [provided by Alliance of Genome Resources, Apr 2022]

MYO19 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.574 CDS is truncated, and there are 2 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 17-36537747-C-T is Pathogenic according to our data. Variant chr17-36537747-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 445616.

BS1

Variant frequency is greater than expected in population nfe. GnomAdExome4 allele frequency = 0.000078 (114/1461842) while in subpopulation NFE AF = 0.0000998 (111/1111986). AF 95% confidence interval is 0.0000839. There are 0 homozygotes in GnomAdExome4. There are 69 alleles in the male GnomAdExome4 subpopulation. Median coverage is 32. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PIGW	NM_001346754.2 link	c.646C>T	p.Arg216*	stop_gained	Exon 2 of 2	ENST00000614443.2	NP_001333683.1	Q7Z7B1
PIGW	NM_001346755.2 link	c.646C>T	p.Arg216*	stop_gained	Exon 2 of 2		NP_001333684.1	Q7Z7B1
PIGW	NM_178517.5 link	c.646C>T	p.Arg216*	stop_gained	Exon 2 of 2		NP_848612.2	Q7Z7B1
MYO19	XM_047436823.1 link	c.-295-3643G>A		intron_variant	Intron 2 of 29		XP_047292779.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PIGW	ENST00000614443.2 link	c.646C>T	p.Arg216*	stop_gained	Exon 2 of 2	1	NM_001346754.2	ENSP00000482202.1		Q7Z7B1

Frequencies

GnomAD3 genomes

AF:

0.0000526

AC:

AN:

152082

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

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:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000478

AC:

AN:

251264

AF XY:

0.0000442

show subpopulations

Gnomad AFR exome

AF:

0.00

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:

0.0000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000780

AC:

114

AN:

1461842

Hom.:

Cov.:

AF XY:

0.0000949

AC XY:

AN XY:

727210

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39696

South Asian (SAS)

AF:

0.0000232

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53404

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000998

AC:

111

AN:

1111986

Other (OTH)

AF:

0.00

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.457

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000526

AC:

AN:

152082

Hom.:

Cov.:

AF XY:

0.0000539

AC XY:

AN XY:

74272

show subpopulations

African (AFR)

AF:

0.0000483

AC:

AN:

41404

American (AMR)

AF:

0.000131

AC:

AN:

15268

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10576

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000588

AC:

AN:

68018

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.544

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000108

Hom.:

Bravo

AF:

0.0000793

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000494

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:3Uncertain:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Hyperphosphatasia with intellectual disability syndrome 5

Pathogenic:2Uncertain:1

May 27, 2021

New York Genome Center

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Aug 16, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Arg216*) in the PIGW gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 289 amino acid(s) of the PIGW protein. This variant is present in population databases (rs147622852, gnomAD 0.009%). This variant has not been reported in the literature in individuals affected with PIGW-related conditions. ClinVar contains an entry for this variant (Variation ID: 445616). 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. -

Mar 12, 2021

Baylor Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Pathogenic:1

Sep 05, 2017

Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not specified

Uncertain:1

Oct 08, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: PIGW c.646C>T (p.Arg216X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, however current evidence is not sufficient to establish loss of function as a mechanism for disease. The variant allele was found at a frequency of 4.8e-05 in 251264 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in PIGW causing Hyperphosphatasia With Mental Retardation Syndrome 5, allowing no conclusion about variant significance. To our knowledge, no occurrence of c.646C>T in individuals affected with Hyperphosphatasia With Mental Retardation Syndrome 5 and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 445616). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.49

BayesDel_noAF

Pathogenic

0.58

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Uncertain

0.67

Eigen_PC

Uncertain

0.44

FATHMM_MKL

Uncertain

0.84

PhyloP100

0.81

Vest4

0.29, 0.29

GERP RS

2.3

Mutation Taster

=165/35

disease causing (ClinVar)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over