15-74890086-C-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_002435.3(MPI):c.13C>T(p.Arg5Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000684 in 1,607,920 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 (★★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000069 (0 hom.)
• Consequence: MPI NM_002435.3 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: -0.256

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]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 63 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 15-74890086-C-T is Pathogenic according to our data. Variant chr15-74890086-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 554184.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MPI	NM_002435.3	c.13C>T	p.Arg5Ter	stop_gained	1/8	ENST00000352410.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MPI	ENST00000352410.9	c.13C>T	p.Arg5Ter	stop_gained	1/8	1	NM_002435.3	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152180 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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

GnomAD4 exome AF: 0.00000687 AC: 10 AN: 1455740 Hom.: 0 Cov.: 31 AF XY: 0.00000690 AC XY: 5 AN XY: 724540

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000719

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152180 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74330

Gnomad4 AFR AF: 0.00

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: 0.00000378

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

MPI-congenital disorder of glycosylation Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Sep 03, 2023	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Sep 28, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jul 21, 2021	For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. ClinVar contains an entry for this variant (Variation ID: 554184). This variant has not been reported in the literature in individuals affected with MPI-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Arg5*) in the MPI gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MPI are known to be pathogenic (PMID: 19862844). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Benign	-0.10
Cadd	Pathogenic	26
Dann	Uncertain	0.98
Eigen	Benign	-0.38
Eigen_PC	Benign	-0.77
FATHMM_MKL	Benign	0.072	N
MutationTaster	Benign	1.0	A;A;A;A;A;N;N;N;N
Vest4		0.61
GERP RS		-1.9

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

Other links and lift over

dbSNP: rs1452559752; hg19: chr15-75182427;