16-8847770-A-G

Variant names:

• chr16-8847770-A-G
• rs398123311
• NM_000303.3:c.686A>G
• PMM2 p.Tyr229Cys

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1 PM2 PM5 PP2 PP3

The NM_000303.3(PMM2):​c.686A>G​(p.Tyr229Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000274 in 1,461,748 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 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. Y229S) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: PMM2 NM_000303.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 5.45
• 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: ClinGen, Orphanet, Labcorp Genetics (formerly Invitae), G2P
• hyperinsulinemic hypoglycemia with polycystic kidney disease

  Inheritance: AR Classification: MODERATE Submitted by: ClinGen

ENSG00000260350 (HGNC:58482):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PM1: In a hotspot region, there are 13 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 chr16-8847770-A-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 92806.
• 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, hyperinsulinemic hypoglycemia with polycystic kidney disease.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.819

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.686A>G	p.Tyr229Cys	missense	Exon 8 of 8	NP_000294.1	A0A0S2Z4J6

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PMM2	ENST00000268261.9	TSL:1 MANE Select	c.686A>G	p.Tyr229Cys	missense	Exon 8 of 8	ENSP00000268261.4	O15305-1
	PMM2	ENST00000565221.5	TSL:1	n.*304A>G		non_coding_transcript_exon	Exon 6 of 6	ENSP00000457932.1	H3BV34
	PMM2	ENST00000566540.5	TSL:1	n.*308A>G		non_coding_transcript_exon	Exon 6 of 6	ENSP00000454284.1	H3BM92

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461748 Hom.: 0 Cov.: 30 AF XY: 0.00000275 AC XY: 2 AN XY: 727186

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53350

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000360 AC: 4 AN: 1111946

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Pathogenic	0.23	D
BayesDel_noAF	Uncertain	0.090
CADD	Uncertain	23
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.87	D
Eigen	Benign	0.10
Eigen_PC	Benign	0.067
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.59	D
MetaRNN	Pathogenic	0.82	D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Benign	1.7	L
PhyloP100		5.5
PrimateAI	Uncertain	0.49	T
PROVEAN	Pathogenic	-5.3	D
REVEL	Pathogenic	0.73
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0020	D
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.92
gMVP		0.86
Mutation Taster		=22/78	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		Details are displayed if max score is > 0.2

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs398123311;

hg19: chr16-8941627;