The Road to Certainty: Diagnosing Arterial Tortuosity Syndrome (ATS)

The journey to a diagnosis of Arterial Tortuosity Syndrome (ATS) can be complex because the condition is so rare and shares many physical traits with more common connective tissue disorders. Because of this, patients are sometimes initially suspected of having conditions like Marfan syndrome, Loeys-Dietz syndrome, or Ehlers-Danlos syndrome ^[1][2].

Navigating Diagnostic Pitfalls

A common diagnostic “trap” occurs when a patient presents with a tall, slender build or flexible joints, leading doctors to suspect Marfan syndrome first ^[3]. In other cases, if the external signs—like loose skin or joint laxity—are subtle or absent, the underlying arterial twisting may be overlooked entirely ^[4]. It is important to note that overlapping conditions like Loeys-Dietz syndrome can also cause diffuse arterial tortuosity, aneurysms, and pulmonary-artery involvement; doctors must use the complete clinical picture alongside molecular testing.

To distinguish ATS, doctors look for its unique “signature”:

• Widespread Tortuosity: While Marfan primarily involves the aorta, ATS frequently involves twisting and looping of arteries throughout the body ^[1].
• Pulmonary Involvement: Significant narrowing or twisting of the pulmonary artery branches (carrying blood to the lungs) is a hallmark of ATS ^[5].
• Inheritance Pattern: Unlike Marfan or Loeys-Dietz, which are usually autosomal dominant (one parent passes it down), ATS is autosomal recessive, meaning a pathogenic variant is typically inherited from each parent ^[1].

The Definitive Genetic Test

The standard way to confirm a diagnosis of ATS is through genetic testing, though clinical evaluation remains important if a panel is negative. This is typically done using Next-Generation Sequencing (NGS), which can take the form of a focused “aortopathy gene panel” or Whole-Exome Sequencing (WES) ^[6][7].

A definitive molecular diagnosis requires finding biallelic pathogenic or likely pathogenic variants (disease-causing mutations on both copies) in the SLC2A10 gene ^[8]. A “variant of uncertain significance” is not diagnostic. Doctors often recommend “cascade testing” for parents to confirm that each parent contributed one mutation, which establishes the “phase” and proves the mutations are on opposite homologous chromosomes ^[7][9].

Mapping the Arteries: Individualized Imaging

Once genetic testing points toward ATS, a “map” of the body’s blood vessels may be considered. Because tortuosity can occur anywhere, imaging only the heart may not be enough, but the extent and interval of imaging must be individualized based on age, symptoms, kidney function, and the risks of sedation and radiation ^[10].

1. Echocardiography: This is the first step to evaluate the heart’s valves and the aortic root. In children, doctors use Z-scores—a way of measuring the aorta relative to a child’s size—to monitor for any dangerous widening ^[5]. In adults, follow-up may use indexed aortic dimensions and absolute size rather than a pediatric Z-score alone.
2. CT Angiography (CTA): This provides high-resolution, 3D images of the arteries in the chest, abdomen, and pelvis ^[4].
3. MRA/MRI (Magnetic Resonance Angiography): This is often an option for monitoring, especially when avoiding radiation is preferred. An MRA can map the “arterial tree” from the brain down to the legs ^[10][11].

A Practical Diagnostic Checklist

To ensure a diagnosis is thorough, your medical team may consider the following framework: