16-8812994-G-T

Variant names:

• chr16-8812994-G-T
• rs940938678
• NM_000303.3:c.527G>T

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_000303.3(PMM2):​c.527G>T​(p.Gly176Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G176S) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: PMM2 NM_000303.3 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.48
• Publications: 0 publications found

Genes affected

PMM2 (HGNC:9115): (phosphomannomutase 2) The protein encoded by this gene catalyzes the isomerization of mannose 6-phosphate to mannose 1-phosphate, which is a precursor to GDP-mannose necessary for the synthesis of dolichol-P-oligosaccharides. Mutations in this gene have been shown to cause defects in glycoprotein biosynthesis, which manifests as carbohydrate-deficient glycoprotein syndrome type I. [provided by RefSeq, Jul 2008]

PMM2 Gene-Disease associations (from GenCC):

• congenital disorder of glycosylation type I

  Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health
• PMM2-congenital disorder of glycosylation

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), G2P, ClinGen, Orphanet
• hyperinsulinemic hypoglycemia with polycystic kidney disease

  Inheritance: AR Classification: MODERATE Submitted by: ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 13 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 12 uncertain in NM_000303.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr16-8812993-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1335984.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 89 curated pathogenic missense variants (we use a threshold of 10). The gene has 24 curated benign missense variants. Gene score misZ: -1.3872 (below the threshold of 3.09). Trascript score misZ: -1.8083 (below the threshold of 3.09). GenCC associations: The gene is linked to PMM2-congenital disorder of glycosylation, congenital disorder of glycosylation type I.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.995
• PP5: Variant 16-8812994-G-T is Pathogenic according to our data. Variant chr16-8812994-G-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 1328987.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000303.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PMM2	NM_000303.3	MANE Select	c.527G>T	p.Gly176Val	missense	Exon 7 of 8	NP_000294.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PMM2	ENST00000268261.9	TSL:1 MANE Select	c.527G>T	p.Gly176Val	missense	Exon 7 of 8	ENSP00000268261.4
	PMM2	ENST00000565221.5	TSL:1	n.*145G>T		non_coding_transcript_exon	Exon 5 of 6	ENSP00000457932.1
	PMM2	ENST00000566540.5	TSL:1	n.*149G>T		non_coding_transcript_exon	Exon 5 of 6	ENSP00000454284.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions as Germline

Significance: Likely pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
1	-	-	PMM2-congenital disorder of glycosylation (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.94	D
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.83	D
MetaRNN	Pathogenic	1.0	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.1	H
PhyloP100		9.5
PrimateAI	Uncertain	0.69	T
PROVEAN	Pathogenic	-8.7	D
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.99
MutPred		0.98		Loss of stability (P = 0.0856)
MVP		0.95
MPC		0.045
ClinPred		1.0	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.98
gMVP		0.95
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs940938678; hg19: chr16-8906851;