chr2-55683831-C-G

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM2PM5PP3_Strong

The NM_033109.5(PNPT1):c.407G>C(p.Arg136Pro) variant causes a missense change. The variant allele was found at a frequency of 0.00000186 in 1,613,130 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R136H) has been classified as Likely pathogenic.

Frequency

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

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

PNPT1
NM_033109.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 6.89

Publications

4 publications found

Variant links:

Genes affected

PNPT1 (HGNC:23166): (polyribonucleotide nucleotidyltransferase 1) The protein encoded by this gene belongs to the evolutionary conserved polynucleotide phosphorylase family comprised of phosphate dependent 3'-to-5' exoribonucleases implicated in RNA processing and degradation. This enzyme is predominantly localized in the mitochondrial intermembrane space and is involved in import of RNA to mitochondria. Mutations in this gene have been associated with combined oxidative phosphorylation deficiency-13 and autosomal recessive nonsyndromic deafness-70. Related pseudogenes are found on chromosomes 3 and 7. [provided by RefSeq, Dec 2012]

PNPT1 Gene-Disease associations (from GenCC):

combined oxidative phosphorylation defect type 13
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Ambry Genetics, PanelApp Australia, Labcorp Genetics (formerly Invitae)
hearing loss disorder
Inheritance: AR Classification: DEFINITIVE Submitted by: G2P
Leigh syndrome
Inheritance: AR Classification: MODERATE Submitted by: ClinGen
hearing loss, autosomal recessive
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
spinocerebellar ataxia type 25
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
autosomal recessive nonsyndromic hearing loss 70
Inheritance: Unknown, AR Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia

PNPT1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr2-55683831-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 587375.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.989

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PNPT1	NM_033109.5 link	c.407G>C	p.Arg136Pro	missense_variant	Exon 5 of 28	ENST00000447944.7	NP_149100.2	Q8TCS8
PNPT1	XM_005264629.3 link	c.167G>C	p.Arg56Pro	missense_variant	Exon 5 of 28		XP_005264686.1
PNPT1	XM_017005172.2 link	c.167G>C	p.Arg56Pro	missense_variant	Exon 4 of 27		XP_016860661.1
PNPT1	XM_047446161.1 link	c.407G>C	p.Arg136Pro	missense_variant	Exon 5 of 20		XP_047302117.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PNPT1	ENST00000447944.7 link	c.407G>C	p.Arg136Pro	missense_variant	Exon 5 of 28	1	NM_033109.5	ENSP00000400646.2		Q8TCS8

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

151844

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000484

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000119

AC:

AN:

251096

AF XY:

0.00000737

show subpopulations

Gnomad AFR exome

AF:

0.000123

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:

0.00000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461286

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

726922

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33448

American (AMR)

AF:

0.00

AC:

AN:

44684

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26124

East Asian (EAS)

AF:

0.00

AC:

AN:

39664

South Asian (SAS)

AF:

0.00

AC:

AN:

86168

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53406

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5746

European-Non Finnish (NFE)

AF:

9.00e-7

AC:

AN:

1111670

Other (OTH)

AF:

0.00

AC:

AN:

60376

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000132

AC:

AN:

151844

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74150

show subpopulations

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

African (AFR)

AF:

0.0000484

AC:

AN:

41342

American (AMR)

AF:

0.00

AC:

AN:

15228

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3466

East Asian (EAS)

AF:

0.00

AC:

AN:

5186

South Asian (SAS)

AF:

0.00

AC:

AN:

4816

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10512

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67980

Other (OTH)

AF:

0.00

AC:

AN:

2086

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.325

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:

0.00

Hom.:

ExAC

AF:

0.0000247

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Jun 13, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 136 of the PNPT1 protein (p.Arg136Pro). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. 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. This variant has not been reported in the literature in individuals affected with PNPT1-related conditions. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt PNPT1 protein function. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

1.0

BayesDel_addAF

Pathogenic

0.20

BayesDel_noAF

Pathogenic

0.29

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.69

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.93

FATHMM_MKL

Pathogenic

1.0

M_CAP

Pathogenic

0.38

MetaRNN

Pathogenic

0.99

MetaSVM

Uncertain

0.57

MutationAssessor

Pathogenic

4.3

PhyloP100

6.9

PrimateAI

Uncertain

0.66

PROVEAN

Pathogenic

-6.4

REVEL

Pathogenic

0.68

Sift

Uncertain

0.0010

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.96

MutPred

0.94

Loss of MoRF binding (P = 0.0918);

MVP

0.79

MPC

0.75

ClinPred

1.0

GERP RS

5.2

Varity_R

0.99

gMVP

0.96

Mutation Taster

=12/88

disease causing

(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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over