7-108472473-CAG-C

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PVS1_ModeratePM2PP5

The NM_001256007.3(PNPLA8):c.2275_2276del(p.Leu759AlafsTer4) variant causes a frameshift change. The variant allele was found at a frequency of 0.00000875 in 1,600,120 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000076 ( 0 hom. )

Consequence

PNPLA8
NM_001256007.3 frameshift

Scores

Not classified

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3U:1

Conservation

PhyloP100: 7.08

Variant links:

Genes affected

PNPLA8 (HGNC:28900): (patatin like phospholipase domain containing 8) This gene encodes a member of the patatin-like phospholipase domain containing protein family. Members of this family are phospholipases which catalyze the cleavage of fatty acids from membrane phospholipids. The product of this gene is a calcium-independent phospholipase. Mutations in this gene have been associated with mitochondrial myopathy with lactic acidosis. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, May 2015]

PNPLA8 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 5 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 0.0315 CDS is truncated, and there are 0 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 7-108472473-CAG-C is Pathogenic according to our data. Variant chr7-108472473-CAG-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 190128.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=2, Uncertain_significance=1}. Variant chr7-108472473-CAG-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PNPLA8	NM_001256007.3 linkuse as main transcript	c.2275_2276del	p.Leu759AlafsTer4	frameshift_variant	11/11	ENST00000257694.13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PNPLA8	ENST00000257694.13 linkuse as main transcript	c.2275_2276del	p.Leu759AlafsTer4	frameshift_variant	11/11	1	NM_001256007.3	P1	Q9NP80-1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152174

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

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

GnomAD3 exomes

AF:

0.0000165

AC:

AN:

242202

Hom.:

AF XY:

0.0000153

AC XY:

AN XY:

130890

show subpopulations

Gnomad AFR exome

AF:

0.000190

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000466

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000760

AC:

AN:

1447946

Hom.:

AF XY:

0.00000972

AC XY:

AN XY:

720412

show subpopulations

Gnomad4 AFR exome

AF:

0.0000920

Gnomad4 AMR exome

AF:

0.0000232

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000238

Gnomad4 FIN exome

AF:

0.0000188

Gnomad4 NFE exome

AF:

0.00000181

Gnomad4 OTH exome

AF:

0.0000334

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152174

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74336

show subpopulations

Gnomad4 AFR

AF:

0.0000483

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:3Uncertain:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Mitochondrial myopathy-lactic acidosis-deafness syndrome

Pathogenic:2

Pathogenic, no assertion criteria provided	literature only	OMIM	Mar 01, 2015	- -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Feb 05, 2021	- -

not provided

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jul 12, 2022

This variant is present in population databases (rs774184465, gnomAD 0.02%). This sequence change creates a premature translational stop signal (p.Leu759Alafs*4) in the PNPLA8 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 24 amino acid(s) of the PNPLA8 protein. This premature translational stop signal has been observed in individual(s) with mitochondrial myopathy with lactic acidosis (PMID: 25512002, 29681094). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 190128). This variant is also known as c.1975_1976delAG. -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Nov 23, 2016

The c.2275_2276delCT variant in the PNPLA8 gene has been reported previously in an individual with a suspected mitochondrial myopathy, with progressive muscle weakness, hypotonia, seizures, poor weight gain, and lactic acidosis, who was compound heterozygous for the c.2275_2276delCT variant and another loss of function variant (Saunders et al., 2015). The c.2275_2276delCT variant causes a frameshift starting with codon Leucine 759, changes this amino acid to an Alanine residue, and creates a premature Stop codon at position 4 of the new reading frame, denoted p.Leu759AlafsX4. This variant is predicted to cause loss of normal protein function through protein truncation. The c.2275_2276delCT variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. We interpret c.2275_2276delCT as a variant of uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over