FLT1

Chr 13

fms related receptor tyrosine kinase 1

Also known as: FLT, FLT-1, VEGFR-1, VEGFR1

This gene encodes VEGFR-1, a receptor tyrosine kinase that binds VEGF-A, VEGF-B, and placental growth factor to regulate angiogenesis, vasculogenesis, and endothelial cell survival during embryonic development and in adulthood. Mutations cause autosomal dominant retinal arterial macroaneurysm with supravalvular pulmonic stenosis, a condition affecting the cardiovascular and ocular systems. The gene is highly constrained against loss-of-function variants (pLI = 1.0, LOEUF = 0.25), indicating that most loss-of-function mutations are likely pathogenic.

OMIMResearchSummary from RefSeq, UniProt
MultiplemechanismLOEUF 0.25
Clinical SummaryFLT1
Population Constraint (gnomAD)
Highly constrained gene — heterozygous loss-of-function variants are very rare in the population (pLI 1.00). One damaged copy is likely sufficient to cause disease.
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Clinical Trials
10 active or recruiting trials — potential therapeutic options may be available

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

LoF intolerant — likely haploinsufficient
LoF Constraint
0.25LOEUF
pLI 1.000
Z-score 6.57
OE 0.15 (0.090.25)
Highly constrained

Highly LoF-intolerant (top ~10% of genes)

Missense Constraint
1.45Z-score
OE missense 0.85 (0.790.91)
611 obs / 720.9 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.15 (0.090.25)
00.351.4
Missense OE0.85 (0.790.91)
00.61.4
Synonymous OE1.01
01.21.6
LoF obs/exp: 10 / 68.9Missense obs/exp: 611 / 720.9Syn Z: -0.08
DN
0.5869th %ile
GOF
0.6444th %ile
LOF
0.55top 25%

This gene has evidence for multiple mechanisms of pathogenicity (loss-of-function and gain-of-function). The Badonyi & Marsh model scores gain-of-function highest among its predictions, but genomic evidence (constraint, ClinVar variant spectrum, and literature) most strongly supports loss-of-function (haploinsufficiency). Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

LOFLOEUF 0.25
GOFprediction above median

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312. Mechanism ranking also informed by gnomAD constraint, ClinVar, and ClinGen data.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

FLT1 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

3D Protein StructureAlphaFold

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

Acute Myeloid Leukemia

Testing Oral Decitabine and Cedazuridine (ASTX727) in Combination With Venetoclax for Higher-Risk Acute Myeloid Leukemia Patients

ACTIVE NOT RECRUITING
NCT04817241Phase PHASE1, PHASE2National Cancer Institute (NCI)Started 2022-02-10
Biospecimen CollectionBone Marrow Aspiration and BiopsyCytarabine
Lung CancerTKI ResistanceEGFR Sensitive Mutation

A Single Center, Single Arm Clinical Study on the Treatment of Advanced Non-small Cell Lung Cancer With Positive EGFR Sensitive Mutations and Failed EGFR TKIs With the Combination of Enrotinib and Paclitaxel Monoclonal Antibody

NOT YET RECRUITING
NCT06048315Phase PHASE3Degan LuStarted 2023-09
AnlotinibPenpulimab
Preeclampsia (PE)Intrauterine Growth Restriction (IUGR)Placental Insufficiency

Statin Intervention for Severe Early-Onset Placental Insufficiency. (STATIN-PRE Trial)

RECRUITING
NCT07098975Phase PHASE2Fundació Institut de Recerca de l'Hospital de la Santa Creu i Sant PauStarted 2026-01-14
Pravastatin 40 mgPlacebo
Acute Myeloid LeukemiaAML, AdultAML With Gene Mutations

Revumenib in Combination With 7+3 + Midostaurin in AML

RECRUITING
NCT06313437Phase PHASE1Richard Stone, MDStarted 2024-12-06
RevumenibMidostaurinCytarabine
Lymphoma, Non-HodgkinMultiple MyelomaAdvanced Solid Tumors

TAPUR: Testing the Use of Food and Drug Administration (FDA) Approved Drugs That Target a Specific Abnormality in a Tumor Gene in People With Advanced Stage Cancer

RECRUITING
NCT02693535Phase PHASE2American Society of Clinical OncologyStarted 2016-03-14
PalbociclibSunitinibTemsirolimus
Pregnancy ComplicationsPre-EclampsiaGrowth Retardation, Intrauterine

Autophagy/Apoptosis Balance in Placental Vascular Pathologies

RECRUITING
NCT06779916Centre Hospitalier Universitaire de NīmesStarted 2025-05-02
Blood testUrine test
Advanced Solid Tumors

Safety of Recombinant Human IL-21-expressing Oncolytic Vaccinia Virus Injection (hV01) in Advanced Tumors

ACTIVE NOT RECRUITING
NCT05914376Phase PHASE1Hangzhou Converd Co., Ltd.Started 2023-07-05
Recombinant human IL-21-expressing oncolytic vaccinia virus injection
Acute Myeloid LeukemiaMyelodysplastic Syndrome With Excess Blasts-2

A Study of Gilteritinib Versus Midostaurin in Combination With Induction and Consolidation Therapy Followed by One-year Maintenance in Patients With Newly Diagnosed Acute Myeloid Leukemia or Myelodysplastic Syndromes With Excess Blasts-2 With FLT3 Mutations Eligible for Intensive Chemotherapy

ACTIVE NOT RECRUITING
NCT04027309Phase PHASE3Stichting Hemato-Oncologie voor Volwassenen NederlandStarted 2019-12-20
GilteritinibMidostaurin
Acute Myeloid Leukemia

Combination of Midostaurin and Gemtuzumab Ozogamicin in First-line Standard Therapy for Acute Myeloid Leukemia (MOSAIC)

RECRUITING
NCT04385290Phase PHASE1, PHASE2Technische Universität DresdenStarted 2020-09-04
MODULE: conventional chemotherapy (Cytarabine+Daunorubicin) in combination with midostaurin+GOMAGNOLIA-trial: Midostaurin associated with conventional chemotherapy (AraC+DNR)+GOMAGNOLIA-trial: conventional chemotherapy (AraC+DNR)+GO
Lymphoma, Non-HodgkinMultiple MyelomaAdvanced Solid Tumors

Canadian Profiling and Targeted Agent Utilization Trial (CAPTUR)

RECRUITING
NCT03297606Phase PHASE2Canadian Cancer Trials GroupStarted 2018-03-23
OlaparibDasatinibNivolumab plus Ipilimumab
Clinical Literature
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