Genetic Variant GMPPB:p.Arg293Pro (chr3-49722038-C-G) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2PM5

The NM_021971.4(GMPPB):c.878G>C(p.Arg293Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,613,470 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R293W) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

GMPPB
NM_021971.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 3.29

Variant links:

Genes affected

GMPPB (HGNC:22932): (GDP-mannose pyrophosphorylase B) This gene is thought to encode a GDP-mannose pyrophosphorylase. The encoded protein catalyzes the conversion of mannose-1-phosphate and GTP to GDP-mannose, a reaction involved in the production of N-linked oligosaccharides. Alternatively spliced transcript variants encoding distinct isoforms have been described. [provided by RefSeq, Jan 2009]

GMPPB links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 4 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr3-49722039-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GMPPB	NM_021971.4 link	c.878G>C	p.Arg293Pro	missense_variant	Exon 8 of 9	ENST00000308388.7	NP_068806.2	Q9Y5P6-1
GMPPB	NM_013334.4 link	c.878G>C	p.Arg293Pro	missense_variant	Exon 8 of 8		NP_037466.3	Q9Y5P6-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GMPPB	ENST00000308388.7 link	c.878G>C	p.Arg293Pro	missense_variant	Exon 8 of 9	1	NM_021971.4	ENSP00000311130.6		Q9Y5P6-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152198

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461272

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

726954

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152198

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74354

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:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Nov 09, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.878G>C (p.R293P) alteration is located in exon 8 (coding exon 8) of the GMPPB gene. This alteration results from a G to C substitution at nucleotide position 878, causing the arginine (R) at amino acid position 293 to be replaced by a proline (P). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.23

BayesDel_addAF

Pathogenic

0.24

BayesDel_noAF

Uncertain

0.11

CADD

Benign

DANN

Uncertain

0.98

DEOGEN2

Pathogenic

0.85

D;.;D

Eigen

Benign

0.058

Eigen_PC

Benign

0.18

FATHMM_MKL

Uncertain

0.97

LIST_S2

Uncertain

0.93

.;D;D

M_CAP

Uncertain

0.25

MetaRNN

Uncertain

0.61

D;D;D

MetaSVM

Uncertain

0.20

MutationAssessor

Benign

2.0

M;M;M

PrimateAI

Uncertain

0.53

PROVEAN

Uncertain

-2.5

N;N;N

REVEL

Uncertain

0.60

Sift

Benign

0.085

T;T;T

Sift4G

Benign

0.24

T;T;T

Polyphen

0.011

B;B;B

Vest4

0.72

MutPred

0.55

Loss of MoRF binding (P = 0.0059);Loss of MoRF binding (P = 0.0059);Loss of MoRF binding (P = 0.0059);

MVP

0.89

MPC

1.0

ClinPred

0.77

GERP RS

5.0

Varity_R

0.52

gMVP

0.87

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