rs143038880

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_024989.4(PGAP1):c.1396C>T(p.Gln466*) variant causes a stop gained change. The variant allele was found at a frequency of 0.00000454 in 1,542,014 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 Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000036 ( 0 hom. )

Consequence

PGAP1
NM_024989.4 stop_gained

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4

Conservation

PhyloP100: 4.11

Publications

3 publications found

Variant links:

Genes affected

PGAP1 (HGNC:25712): (post-GPI attachment to proteins inositol deacylase 1) The protein encoded by this gene functions early in the glycosylphosphatidylinositol (GPI) biosynthetic pathway, catalyzing the inositol deacylation of GPI. The encoded protein is required for the production of GPI that can attach to proteins, and this may be an important factor in the transport of GPI-anchored proteins from the endoplasmic reticulum to the Golgi. Defects in this gene are a cause an autosomal recessive form of cognitive impairment. [provided by RefSeq, Jul 2017]

PGAP1 Gene-Disease associations (from GenCC):

intellectual disability, autosomal recessive 42
Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
autosomal recessive non-syndromic intellectual disability
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
autosomal recessive spastic paraplegia type 67
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

PGAP1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 2-196875776-G-A is Pathogenic according to our data. Variant chr2-196875776-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 222978.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PGAP1	NM_024989.4 link	c.1396C>T	p.Gln466*	stop_gained	Exon 14 of 27	ENST00000354764.9	NP_079265.2	Q75T13-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PGAP1	ENST00000354764.9 link	c.1396C>T	p.Gln466*	stop_gained	Exon 14 of 27	1	NM_024989.4	ENSP00000346809.3		Q75T13-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152158

Hom.:

Cov.:

show subpopulations

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000204

AC:

AN:

245412

AF XY:

0.00000754

show subpopulations

Gnomad AFR exome

AF:

0.0000638

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:

0.0000358

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000360

AC:

AN:

1389856

Hom.:

Cov.:

AF XY:

0.00000144

AC XY:

AN XY:

694312

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

31790

American (AMR)

AF:

0.00

AC:

AN:

43284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25262

East Asian (EAS)

AF:

0.00

AC:

AN:

39096

South Asian (SAS)

AF:

0.00

AC:

AN:

83320

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53068

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5554

European-Non Finnish (NFE)

AF:

0.00000476

AC:

AN:

1050748

Other (OTH)

AF:

0.00

AC:

AN:

57734

⚠️ 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.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152158

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74338

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41458

American (AMR)

AF:

0.00

AC:

AN:

15276

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5206

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10596

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68002

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.550

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000434

Hom.:

Bravo

AF:

0.0000227

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000247

AC:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Intellectual disability, autosomal recessive 42

Pathogenic:3

May 26, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 222978). This premature translational stop signal has been observed in individual(s) with clinical features of autosomal recessive PGAP1-related condition (PMID: 25823418). This variant is present in population databases (rs143038880, gnomAD 0.003%). This sequence change creates a premature translational stop signal (p.Gln466*) in the PGAP1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in PGAP1 are known to be pathogenic (PMID: 17711852, 26050939, 27848944). -

May 24, 2021

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

- -

Apr 20, 2023

Duke University Health System Sequencing Clinic, Duke University Health System

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:research

- -

not provided

Pathogenic:1

Feb 15, 2023

GeneDx

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Observed with a second loss-of-function PGAP1 variant on the opposite allele (in trans) in a male child with cortical visual impairment, hypotonia, and global developmental delay (Williams et al., 2015); Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed at a significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 27206732, 26563290, 25823418, 33198937) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.58

BayesDel_noAF

Pathogenic

0.62

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Pathogenic

0.82

Eigen_PC

Pathogenic

0.67

FATHMM_MKL

Uncertain

0.93

PhyloP100

4.1

Vest4

0.54

GERP RS

5.3

Mutation Taster

=1/199

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over