Dental OSCE (Objective Structured Clinical Examination) Practice Exam

What genetic heredity pattern is associated with Hereditary Hemorrhagic Telangiectasia (HHT)?

1. Autosomal recessive

2. X-linked dominant

3. Autosomal dominant

4. Mitochondrial inheritance

The correct answer is: Autosomal dominant

Hereditary Hemorrhagic Telangiectasia (HHT) is primarily associated with an autosomal dominant inheritance pattern. This means that the condition can be passed down through families with only one copy of the mutated gene needed for a person to be affected. Each child of an affected individual has a 50% chance of inheriting the disorder. In autosomal dominant conditions like HHT, mutations are typically present in genes that play crucial roles in vascular development and function. The common genes involved in HHT, such as ENG (endoglin) and ACVRL1 (activin A receptor-like type 1), are located on autosomes, which are the non-sex chromosomes. This pattern allows for the variability in expressivity and penetrance, which means that not all individuals with the mutation will exhibit the same symptoms or severity of the condition. The dominant nature of the gene means that it can affect both males and females equally, highlighting its importance in understanding the genetic counseling and risk assessment for families affected by HHT.