Any amelogenesis imperfecta in which the cause of the disease is a mutation in the LAMB3 gene. The disease is amelogenesis imperfecta type 1A (MONDO_0007094). Also known as: AI1A, LAMB3 amelogenesis imperfecta, amelogenesis imperfecta caused by mutation in LAMB3, amelogenesis imperfecta hypoplastic type IA, amelogenesis imperfecta type IA.