Matriptase-2 consists of an N-terminal transmembrane domain (TM), one SEA domain, two CUB domains, three LDL receptor repeats (LDLR), and a C-terminal trypsin-like protease domain. Relative positions of nonsense (♠), missense (◆), splicing junction (♣) and frameshift (♥) mutations identified in patients with IRIDA are indicated.