rs1274794195

Variant names:

• chr16-8811635-CAGAA-C
• rs1274794195
• NM_000303.3:c.451_454delGAAA

Variant summary

Our verdict is Pathogenic. The variant received 20 ACMG points: 20P and 0B. PVS1 PM2 PP3_Moderate PP5_Very_Strong

The NM_000303.3(PMM2):​c.451_454delGAAA​(p.Glu151fs) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000276 in 1,451,700 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000028 (0 hom.)
• Consequence: PMM2 NM_000303.3 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 9.70
• Publications: 1 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: G2P, Labcorp Genetics (formerly Invitae), Orphanet, PanelApp Australia, ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 20 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 16-8811635-CAGAA-C is Pathogenic according to our data. Variant chr16-8811635-CAGAA-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 558721.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PMM2	NM_000303.3	MANE Select	c.451_454delGAAA	p.Glu151fs	frameshift	Exon 6 of 8	NP_000294.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PMM2	ENST00000565221.5	TSL:1	n.*66-2_*67delAGAA		splice_region non_coding_transcript_exon	Exon 4 of 6	ENSP00000457932.1
	PMM2	ENST00000566540.5	TSL:1	n.*70-2_*71delAGAA		splice_region non_coding_transcript_exon	Exon 4 of 6	ENSP00000454284.1
	PMM2	ENST00000268261.9	TSL:1 MANE Select	c.448-2_449delAGAA	p.Lys150fs	frameshift splice_acceptor splice_region intron	Exon 6 of 8	ENSP00000268261.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251184 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000881

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000276 AC: 4 AN: 1451700 Hom.: 0 AF XY: 0.00000553 AC XY: 4 AN XY: 722970

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33300

American (AMR) AF: 0.00 AC: 0 AN: 44698

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26040

East Asian (EAS) AF: 0.00 AC: 0 AN: 39650

South Asian (SAS) AF: 0.00 AC: 0 AN: 86006

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53364

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5744

European-Non Finnish (NFE) AF: 0.00000363 AC: 4 AN: 1102856

Other (OTH) AF: 0.00 AC: 0 AN: 60042

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000203476), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions as Germline

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
4	-	-	PMM2-congenital disorder of glycosylation (4)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		9.7
Mutation Taster		=1/199	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.71		Position offset: 7
DS_AL_spliceai		0.98		Position offset: 3

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

Other links and lift over

dbSNP: rs1274794195; hg19: chr16-8905492;