1-43338231-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_005373.3(MPL):c.212G>T(p.Arg71Leu) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.000000684 in 1,461,352 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign 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. R71Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MPL NM_005373.3 missense, splice_region
• Scores: Splicing: ADA: 0.9994
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.70

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• 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/exons	MANE	UniProt
MPL	NM_005373.3	c.212G>T	p.Arg71Leu	missense_variant, splice_region_variant	2/12	ENST00000372470.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MPL	ENST00000372470.9	c.212G>T	p.Arg71Leu	missense_variant, splice_region_variant	2/12	1	NM_005373.3	P1
MPL	ENST00000413998.7	c.191G>T	p.Arg64Leu	missense_variant, splice_region_variant	2/12	1
MPL	ENST00000638732.1	n.212G>T		splice_region_variant, non_coding_transcript_exon_variant	2/10	1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250418 Hom.: 0 AF XY: 0.00000738 AC XY: 1 AN XY: 135460

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000885

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461352 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 726998

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Benign	-0.10	T
BayesDel_noAF	Benign	-0.39
Cadd	Uncertain	25
Dann	Uncertain	0.98
DEOGEN2	Uncertain	0.46	T;.
Eigen	Benign	-0.17
Eigen_PC	Benign	0.037
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Benign	0.72	T;T
M_CAP	Benign	0.021	T
MetaRNN	Benign	0.26	T;T
MetaSVM	Benign	-0.87	T
MutationAssessor	Benign	0.0	N;.
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.36	T
PROVEAN	Benign	-1.2	N;.
REVEL	Benign	0.12
Sift	Benign	0.40	T;.
Sift4G	Uncertain	0.013	D;.
Polyphen		0.078	B;.
Vest4		0.15
MutPred		0.53		Loss of disorder (P = 0.0521);.;
MVP		0.86
MPC		0.30
ClinPred		0.31	T
GERP RS		4.7
Varity_R		0.081
gMVP		0.72

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.60		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.60		Position offset: 0

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

Publications

LitVar

Other links and lift over

dbSNP: rs368753117; hg19: chr1-43803902;