Type

Gene/protein

Gene description

Mutation types

Mutation locations

HHT1

ENG/Endoglin

Member of TGFβ receptor complex

Point mutations; duplications; deletions; insertions

Exons 1 - 14;

HHT2

ACVRL1/ALK1

Type 1 cell surface receptor in TGFβ

superfamily

Point mutations; duplications; deletions; insertions

Exons 2 - 10; Introns 3 - 9

HHT associated with Juvenile Polyposis

MADH4/Smad4

Transcription factor in TGFβ

Point mutations; duplications; deletions; insertions

Exons 4, 7, 10 - 13

HHT-5

BMP9 (GDF2)/BMP9

TGFβ

ligand

Point mutations

Exons 1, 2