Penetrance

Rare examples of non-penetrance in LDS have been documented. In some instances, non-penetrance is explained by mosaicism .

Source: GeneReviews — "Loeys-Dietz Syndrome"

Diagnostic Criteria

No consensus clinical diagnostic criteria for Loeys-Dietz syndrome (LDS) have been published.

Suggestive Findings

LDS should be suspected in individuals with the following vascular, skeletal, craniofacial, cutaneous, allergic/inflammatory, ocular, and family history findings .

Vascular

• Dilatation or dissection of the aorta and other arteries. Aortic root dilatation is seen in more than 95% of probands; the aortic root is the most common site for a dissection to occur. In rare circumstances, aneurysms or dissections can be seen in other arteries in the head, chest, abdomen, or extremities in the absence of aortic involvement.

• Other arterial aneurysms and tortuosity

Source: GeneReviews — "Loeys-Dietz Syndrome"

Differential Diagnosis

Marfan Syndrome and Shprintzen-Goldberg Syndrome

FBN1-related Marfan syndrome is a systemic disorder with a high degree of clinical variability. Cardinal manifestations involve the ocular, skeletal, and cardiovascular systems. Cardiovascular manifestations include dilatation of the aorta at the level of the sinuses of Valsalva, a predisposition for aortic tear and rupture, mitral valve prolapse with or without regurgitation, tricuspid valve prolapse, and enlargement of the proximal pulmonary artery. Marfan syndrome is caused by pathogenic variants in FBN1 and inherited in an autosomal dominant manner.

Source: GeneReviews — "Loeys-Dietz Syndrome"

Management Guidelines

An extensive review of management guidelines for Loeys-Dietz syndrome (LDS) has been published (full text). Evaluations Following Initial Diagnosis To establish the extent of disease and needs in an individual diagnosed with LDS, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended. Table 6. Loeys-Dietz Syndrome: Recommended Evaluations Following Initial Diagnosis

Source: GeneReviews — "Loeys-Dietz Syndrome"

Clinical Guidance

The following should be avoided:

• Contact sports, competitive sports, and isometric exercise. Note: Individuals can and should remain active with aerobic activities performed in moderation.

• Agents that stimulate the cardiovascular system, including routine use of decongestants or triptan medications for migraine headache management

• Activities that cause joint injury or pain

• For individuals at risk for recurrent pneumothorax, breathing against a resistance (e.g., playing a brass instrument) or positive pressure ventilation (e.g., scuba diving)

Source: GeneReviews — "Loeys-Dietz Syndrome"

Surveillance Guidelines

To monitor existing manifestations, the individual's response to supportive care, and the emergence of new manifestations, the evaluations summarized in are recommended. Table 8. Loeys-Dietz Syndrome: Recommended Surveillance

Source: GeneReviews — "Loeys-Dietz Syndrome"