Understanding the Causes of Vascular Conditions

Vessels are colored orange against a black background. They start off with thicker branches on the top right and become more fibrous and narrow at the bottom left.

Stock image of blood vessels.

Blood vessels are responsible for transporting oxygen throughout the body. Malformations in blood vessels are rare diseases that can lead to a variety of health problems. People with these vascular conditions tend to have hard-to-detect genetic causes because the pathogenic variant (previously known as a mutation) only occurs in some tissues and not in the whole body. This occurrence is called somatic mosaicism.

Turner syndrome occurs when a female is missing part or all of an X chromosome. Common disorders of the vascular system in Turner syndrome include lymphedema and aortic coarctation. In rare cases, a person with Turner syndrome can also have other vascular malformations that are associated with secondary conditions. In a study led by the Sheppard Lab, researchers evaluated two patients with Turner syndrome who also had vascular malformations.

  • Historically, researchers believed that vascular conditions are a rare occurrence that is a symptom of Turner syndrome.
  • In the study, the researchers found that the vascular conditions observed in the two patients were not caused by the absent X chromosome. Instead, the vascular malformations were caused by a somatic pathogenic variant PIK3CA.
  • In the study, 2 out of 345 Turner syndrome were evaluated for a vascular malformation, which is about 1 percent of the group. This percentage is similar to the expected incidence of vascular malformations in the general population.
  • Overall, the findings indicate that some vascular malformations are a separate condition from Turner syndrome. Therefore, healthcare providers should not consider it as part of the syndrome’s spectrum, and they may consider PIK3CA-related therapies if their patients have severe vascular malformations.

Learn more about the Developmental Endocrinology, Metabolism, Genetics & Endocrine Oncology Affinity Group: https://www.nichd.nih.gov/about/org/dir/affinity-groups/DEMG-EO.

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