SNP Shot: Genomic Insights

Hereditary angioedema (HAE) is a medical condition marked by recurring episodes of significant swelling known as angioedema. The most frequently affected body parts are the extremities (arms and legs), face, digestive system, and respiratory tract. Angioedema attacks can be triggered by minor injuries or psychological stress, but often occur without any identifiable cause. When the intestinal tract is involved, individuals experience intense abdominal pain, sickness, and vomiting. Swelling in the throat can obstruct breathing, potentially leading to a life-threatening airway blockage. Approximately one-third of individuals with HAE experience a non-pruritic (non-itchy) rash called erythema marginatum during an attack.

HAE symptoms usually manifest in childhood and intensify during puberty. Without treatment, patients typically experience an angioedema episode every one to two weeks, with most attacks lasting approximately three to four days. However, the frequency and duration of these attacks vary considerably among individuals with HAE, even within the same family.

Hereditary angioedema is classified into three types: type I, type II, and type III. These types are differentiated by their specific underlying causes and the levels of a protein called C1 inhibitor in the blood. The clinical presentation (signs and symptoms) is similar across all three types. Initially, type III was believed to affect only women, but cases involving affected males have since been identified.

Inheritance:

HAE follows an autosomal dominant inheritance pattern. This means that having only one copy of the mutated gene in each cell is enough to cause the condition. In some instances, a person inherits the mutated gene from a parent who also has HAE. In other cases, the condition arises from a new genetic mutation, occurring in individuals with no family history of the disorder.