Defects in KLK4 are the cause of amelogenesis imperfecta hypomaturation type 2A1 (AI2A1) [MIM:204700]. AI2A1 is an autosomal recessive defect of enamel formation. The disorder involves both primary and secondary dentitions. The teeth have a shiny agar jelly appearance and the enamel is softer than normal. Brown pigment is present in middle layers of enamel.
Belongs to the peptidase S1 family. Kallikrein subfamily. Contains 1 peptidase S1 domain.