Contiguous deletion and duplication mutations resulting in type 1 hereditary angioneurotic edema

Mutations that cause low antigenic and functional levels of C1 inhibitor protein result in type 1 hereditary angioneurotic edema. This disease is characterized by episodic edema leading to considerable morbidity and sometimes death. We present here two novel mutations in the reactive center coding region. One mutation is a deletion of an imperfect palindrome encompassing nucleotides 1395–1428 and the other is a direct duplication of nucleotides 1414–1433. These mutations do not depend on improper pairing of direct repeats, but may form as a consequence of a peculiar consensus sequence or an alternative secondary structure.