Is MPL p.Pro136Arg (c.407C>G) pathogenic?

MPL p.Pro136Arg (c.407C>G) is classified Likely pathogenic in MPL (ClinVar, Multiple submitters, 4 submitters; last evaluated 2025-10-09). AlphaMissense: likely pathogenic (0.7815); Very rare (popmax 0.00525%, nfe); Associated with congenital amegakaryocytic thrombocytopenia 1.

What condition is associated with MPL p.Pro136Arg (c.407C>G)?

MPL p.Pro136Arg (c.407C>G) is associated with congenital amegakaryocytic thrombocytopenia 1, primary myelofibrosis, thrombocythemia 2 (ClinVar).

How common is MPL p.Pro136Arg (c.407C>G) in the general population?

MPL p.Pro136Arg (c.407C>G) is very rare (popmax 0.00525%, nfe) (gnomAD).

How is Congenital amegakaryocytic thrombocytopenia inherited?

Typically Autosomal recessive (Orphanet). A genetic counselor can assess individual risk for a family.

What do computational predictors say about MPL p.Pro136Arg (c.407C>G)?

AlphaMissense predicts likely pathogenic (score 0.7815) — an in-silico prediction, not a clinical call.

MPL p.Pro136Arg

c.407C>G · rs764904424 · VCV2445438

Likely pathogenic Multiple submitters

Classification

Likely pathogenic

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 4 submitters

AlphaMissense

likely pathogenic

0.7815 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00525%, nfe)

Missense predictors

3/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

congenital amegakaryocytic thrombocytopenia 1

Computational evidence

Protein change
AlphaMissense	0.7815	likely pathogenic ✓ concordant with ClinVar · top 8% in MPL
REVEL	0.801	moderately pathogenic-leaning
SaProt	LLR -12.14	damaging
⇒ AlphaMissense, REVEL and SaProt all call this damaging.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 6	GERP 1.9, phastCons 1
Regional constraint	o/e 0.80	unconstrained · MANE · 8,947 bp · p 8.9e-06 · regional, not allelic
Overall
CADD	24.1	PHRED · no single calibrated threshold — expert panels disagree

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00525% European (non-Finnish) · 62/1,180,028 alleles

Filtering AF 0.00418% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0038%

Overall 0.00403% 65/1,613,968 alleles · very rare

Ancestry group	Frequency	1 in
European (non-Finnish)grpmax	0.00525%	19,033
East Asian	0.00223%	44,888
Remaining individualsnot grpmax-eligible	0.0016%	62,464
African / African-American	0.00133%	74,928

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: MPL
Protein: p.Pro136Arg
Coding: c.407C>G
MANE Select: NM_005373
dbSNP: rs764904424
Type: single nucleotide variant
Location: chr1:43339286 (GRCh38)
Gene constraint: LOEUF 1.022 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 73.44 · 1 PDB
Residue 136: a UniProt-annotated variant site (in camt1); an α-helix

Full MPL gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

congenital amegakaryocytic thrombocytopenia 1 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: primary myelofibrosis thrombocythemia 2 congenital amegakaryocytic thrombocytopenia

For Congenital amegakaryocytic thrombocytopenia (Orphanet):

Inheritance: Autosomal recessive
Onset: Neonatal

Similar variants

MPL p.Pro136His Likely pathogenic ★★ same residue
MPL p.Pro136Leu Pathogenic/Likely pathogenic ★★ ⚠ same residue
MPL p.Pro136= Likely benign ★ same residue
MPL p.Pro136Ala Likely pathogenic ★ ⚠ same residue
MPL c.1165+1G>C Likely pathogenic ★★ same condition
MPL c.1166-1G>C Likely pathogenic ★★ same condition
MPL c.1468+2T>C Pathogenic/Likely pathogenic ★★ same condition
MPL c.1469-2A>T Pathogenic/Likely pathogenic ★★ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/mpl-p-pro136arg (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown