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 SERPING1 gene, which codes for C1-INH. HAE with quantitatively and qualitatively normal C1-INH (type III) is often caused by a mutation in the F12 gene and no mutations in the SERPING1 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. HAE clinically manifests with intermittent attacks of swelling of the subcutaneous tissue or submucosal layers of the respiratory and gastrointestinal tract. Young children are typically asymptomatic, and those affected by HAE usually present with symptoms in their early 20s. This article describes the case of very early onset of hereditary angioedema caused by C1-INH deficiency in a 2-year-old boy who experienced recurrent episodes of hand and abdominal angioedema not associated with urticaria or pruritus. His father suffered from severe HAE due to a de novo mutation of the SERPING1 gene. The same mutation of the SERPING1 gene was detected in his son at the age of 9-months prior to the occurrence of angioedema symptoms, during genetic family counseling. This paper advances the understanding of HAE and highlights the importance of genetic counseling of families with HAE to avoid late or inaccurate diagnosis and to initiate treatment on time.