15-74897636-G-C

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2PP3

The NM_002435.3(MPI):c.1178G>C(p.Gly393Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000322 in 1,614,212 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 (★★).

Frequency

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

Exomes 𝑓: 0.000034 ( 0 hom. )

Consequence

MPI
NM_002435.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:6

Conservation

PhyloP100: 9.46

Variant links:

Genes affected

MPI (HGNC:7216): (mannose phosphate isomerase) Phosphomannose isomerase catalyzes the interconversion of fructose-6-phosphate and mannose-6-phosphate and plays a critical role in maintaining the supply of D-mannose derivatives, which are required for most glycosylation reactions. Mutations in the MPI gene were found in patients with carbohydrate-deficient glycoprotein syndrome, type Ib. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2014]

MPI links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.798

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MPI	NM_002435.3 link	c.1178G>C	p.Gly393Ala	missense_variant	Exon 8 of 8	ENST00000352410.9	NP_002426.1	P34949-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MPI	ENST00000352410.9 link	c.1178G>C	p.Gly393Ala	missense_variant	Exon 8 of 8	1	NM_002435.3	ENSP00000318318.6		P34949-1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152204

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000187

AC:

AN:

251494

Hom.:

AF XY:

0.000132

AC XY:

AN XY:

135922

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.00133

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000335

AC:

AN:

1461890

Hom.:

Cov.:

AF XY:

0.0000275

AC XY:

AN XY:

727246

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00110

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:

0.0000197

AC:

AN:

152322

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74482

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.000131

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:

0.000110

ExAC

AF:

0.000189

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

MPI-congenital disorder of glycosylation

Uncertain:4

Jun 28, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 393 of the MPI protein (p.Gly393Ala). This variant is present in population databases (rs201815588, gnomAD 0.1%). This missense change has been observed in individual(s) with congenital disorder of glycosylation type 1b (PMID: 32905087). ClinVar contains an entry for this variant (Variation ID: 317143). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. 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. -

Feb 21, 2020

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Aug 30, 2018

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -

not specified

Uncertain:1

Mar 24, 2025

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: MPI c.1178G>C (p.Gly393Ala) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00019 in 251494 control chromosomes (gnomAD). This frequency is not significantly higher than estimated for a pathogenic variant in MPI causing Congenital Disorder Of Glycosylation Type 1B (0.00019 vs 0.0011), allowing no conclusion about variant significance. c.1178G>C has been reported in the literature in an individual affected with Congenital Disorder Of Glycosylation Type 1B (Muhlhausen_2020). These data do not allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 32905087). ClinVar contains an entry for this variant (Variation ID: 317143). Based on the evidence outlined above, the variant was classified as uncertain significance. -

not provided

Uncertain:1

Jun 14, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Observed with a second MPI variant but it is not known whether the variants occurred on the same (in cis) or on different (in trans) chromosomes; this individual is reported with teenage-onset cerebral venous sinus thrombosis as the first and only presenting symptom followed by absent mannose phosphate isomerase activity in leukocytes (Mhlhausen C et al., 2020); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 32905087) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.65

BayesDel_addAF

Pathogenic

0.28

BayesDel_noAF

Pathogenic

0.59

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.95

D;.;.;D;.

Eigen

Pathogenic

0.78

Eigen_PC

Pathogenic

0.67

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.91

D;D;D;D;D

M_CAP

Pathogenic

0.71

MetaRNN

Pathogenic

0.80

D;D;D;D;D

MetaSVM

Pathogenic

0.98

MutationAssessor

Pathogenic

3.2

M;.;.;.;.

PrimateAI

Uncertain

0.54

PROVEAN

Pathogenic

-5.6

D;N;D;D;D

REVEL

Pathogenic

0.90

Sift

Pathogenic

0.0

D;D;D;D;D

Sift4G

Pathogenic

0.0

D;D;D;D;D

Polyphen

1.0

D;.;.;.;D

Vest4

0.69

MVP

0.91

MPC

0.76

ClinPred

0.55

GERP RS

5.6

Varity_R

0.89

gMVP

0.89

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