rs770457041

Variant names:

• chr1-43340501-GC-G
• rs770457041
• NM_005373.3:c.972delC

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1 PP5_Very_Strong

The NM_005373.3(MPL):​c.972delC​(p.Arg325GlufsTer44) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000479 in 1,461,890 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. P324P) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: MPL NM_005373.3 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: -0.722
• Publications: 1 publications found

Genes affected

MPL (HGNC:7217): (MPL proto-oncogene, thrombopoietin receptor) In 1990 an oncogene, v-mpl, was identified from the murine myeloproliferative leukemia virus that was capable of immortalizing bone marrow hematopoietic cells from different lineages. In 1992 the human homologue, named, c-mpl, was cloned. Sequence data revealed that c-mpl encoded a protein that was homologous with members of the hematopoietic receptor superfamily. Presence of anti-sense oligodeoxynucleotides of c-mpl inhibited megakaryocyte colony formation. The ligand for c-mpl, thrombopoietin, was cloned in 1994. Thrombopoietin was shown to be the major regulator of megakaryocytopoiesis and platelet formation. The protein encoded by the c-mpl gene, CD110, is a 635 amino acid transmembrane domain, with two extracellular cytokine receptor domains and two intracellular cytokine receptor box motifs . TPO-R deficient mice were severely thrombocytopenic, emphasizing the important role of CD110 and thrombopoietin in megakaryocyte and platelet formation. Upon binding of thrombopoietin CD110 is dimerized and the JAK family of non-receptor tyrosine kinases, as well as the STAT family, the MAPK family, the adaptor protein Shc and the receptors themselves become tyrosine phosphorylated. [provided by RefSeq, Jul 2008]

MPL Gene-Disease associations (from GenCC):

• thrombocythemia 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics, ClinGen
• congenital amegakaryocytic thrombocytopenia

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, Ambry Genetics
• congenital amegakaryocytic thrombocytopenia 1

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• familial thrombocytosis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• hereditary isolated aplastic anemia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 16 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PP5: Variant 1-43340501-GC-G is Pathogenic according to our data. Variant chr1-43340501-GC-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 435886.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_005373.3. 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
	MPL	NM_005373.3	MANE Select	c.972delC	p.Arg325GlufsTer44	frameshift	Exon 6 of 12	NP_005364.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MPL	ENST00000372470.9	TSL:1 MANE Select	c.972delC	p.Arg325GlufsTer44	frameshift	Exon 6 of 12	ENSP00000361548.3
	MPL	ENST00000413998.7	TSL:1	c.951delC	p.Arg318GlufsTer44	frameshift	Exon 6 of 12	ENSP00000414004.3
	MPL	ENST00000638732.1	TSL:1	n.972delC		non_coding_transcript_exon	Exon 6 of 10

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000795 AC: 2 AN: 251482 AF XY: 0.0000147

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000109

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461890 Hom.: 0 Cov.: 32 AF XY: 0.00000550 AC XY: 4 AN XY: 727248

African (AFR) AF: 0.00 AC: 0 AN: 33480

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

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.000176 AC: 7 AN: 39700

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

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
2	-	-	Congenital amegakaryocytic thrombocytopenia (2)
1	-	-	Essential thrombocythemia;C1327915:Congenital amegakaryocytic thrombocytopenia (1)
1	-	-	Primary myelofibrosis;C3275998:Thrombocythemia 2;C5882667:Congenital amegakaryocytic thrombocytopenia 1 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		-0.72
Mutation Taster		=7/193	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs770457041; hg19: chr1-43806172;