There are several clinical evaluations that are currently pursued together to determine a diagnosis of Loeys-Dietz syndrome.
If there is suspicion of LDS, it is recommended that individuals be evaluated by a geneticist who is familiar with connective tissue disorders. During the initial visit, a detailed family and medical history will be taken and a comprehensive physical examination will be conducted to evaluate the skeletal, craniofacial and skin-related features that are typically present in individuals with LDS.
If there is continued suspicion of LDS, an echocardiogram (ultrasound imaging of the heart) should be performed to assess if there is aortic enlargement and/or other structural heart defects that are consistent with the diagnosis. A consultation with a cardiologist will be necessary to help interpret the cardiac findings.
A physician may also suggest further imaging of the arteries throughout the body. This is done by obtaining a CTA (CT angiogram or computed tomography angiogram) or MRA (MR angiogram or magnetic resonance angiogram) of the entire arterial tree (head, neck, chest, pelvis and abdomen). These imaging studies will detect aneurysms in other arteries.
Three-dimensional reconstruction (3D) of CTA or MRA imaging is recommended to check for arterial tortuosity, a common finding in individuals with LDS, particularly in the neck. This finding in itself does not typically cause medical concern but can suggest more evidence to support the diagnosis of LDS.
Genetic testing for mutations (gene changes) within the TGFBR1, TGFBR2, SMAD3, TGFB2, SMAD2 and TGFB3 genes is clinically available if there is high suspicion of the diagnosis. This test should be ordered by a geneticist, who will be able to accurately interpret and convey the results of the testing. A geneticist will also be able to interpret the family history and determine if genetic testing for other family members is appropriate. If a gene mutation is found in a child, it is typically recommended to test the parents for the same mutation to give accurate recurrence risk information. Testing of offspring of an adult diagnosed with LDS is always recommended.
A diagnosis is established in a person without a family history of LDS when they present with a genetic variant in one of the above-mentioned genes and either of the following:
- Aortic root enlargement or type A dissection
- Characteristic features of LDS, includings vascular, skin, skeletal and/or craniofacial manifestations found in any combination.
A diagnosis is established in a person with documented family history of LDS based on molecular genetic testing even if other features, including vascular involvement, are not yet apparent.
Last Updated January 31, 2020