NM_000303.3:c.178G>A

Variant names:

• chr16-8801910-G-A
• NM_000303.3:c.178G>A

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_000303.3(PMM2):​c.178G>A​(p.Val60Met) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000141 in 1,414,380 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V60L) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: PMM2 NM_000303.3 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.34

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]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PM1: In a chain Phosphomannomutase 2 (size 244) in uniprot entity PMM2_HUMAN there are 79 pathogenic changes around while only 2 benign (98%) 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 chr16-8801910-G-T is described in Lovd as [Pathogenic].
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PMM2	NM_000303.3	c.178G>A	p.Val60Met	missense_variant, splice_region_variant	Exon 2 of 8	ENST00000268261.9	NP_000294.1
PMM2	XM_047434215.1	c.6G>A	p.Met2Ile	missense_variant, splice_region_variant	Exon 1 of 6		XP_047290171.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PMM2	ENST00000268261.9	c.178G>A	p.Val60Met	missense_variant, splice_region_variant	Exon 2 of 8	1	NM_000303.3	ENSP00000268261.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000141 AC: 2 AN: 1414380 Hom.: 0 Cov.: 24 AF XY: 0.00000142 AC XY: 1 AN XY: 706232

Gnomad4 AFR exome AF: 0.00

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: 0.00000187

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.44
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.31
CADD	Pathogenic	36
DANN	Uncertain	1.0
Eigen	Pathogenic	0.82
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.81	T
M_CAP	Pathogenic	0.39	D
MetaRNN	Pathogenic	0.79	D
PROVEAN	Benign	-1.6	N
Sift	Uncertain	0.020	D
Sift4G	Benign	0.073	T
Vest4		0.71
MVP		0.86
ClinPred		0.91	D
GERP RS		5.7
RBP_binding_hub_radar		0.85
RBP_regulation_power_radar		2.6

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.53		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.53		Position offset: -49
DS_DL_spliceai		0.46		Position offset: 0

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr16-8895767;