Case Report: Early presentation of hereditary angioedema symptoms in a 2-year-old boy.

Hereditary angioedema (HAE) is a rare autosomal-dominant disease that is caused by a deficiency (type I) or dysfunction (type II) of the C1 inhibitor (C1-INH) due to a mutation in the gene, which codes for C1-INH. HAE with quantitatively and qualitatively normal C1-INH (type III) is often caused by a mutation in the gene and no mutations in the gene and is a group of very rare diseases. The C1 esterase inhibitor (C1-INH) is a major regulator of critical enzymes that are implicated in the cascades of bradykinin generation, which increases vascular permeability and allows the flow of fluids into the extracellular space, resulting in angioedema.