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It's Scientific Sunday and Genetics 101 with Ryan Rodarmer, Director of Genetic Education

Updated: May 1, 2023

Today is Scientific Sunday at Aortic Hope and we are excited to continue our Genetics 101 Series with Ryan Rodarmer.


Over the next couple of weeks, Ryan will discuss a variety of topics related to genetics. Use these discussions as a way to have a conversation with your physician.


Loeys-Dietz Syndrome:


A Lesser-Known but Important Aortic Disorder


In my previous article, we explored the world of Marfan syndrome, likely the most well-known genetic syndrome affecting the body's connective tissue. We emphasized the importance of spreading awareness and understanding among not only healthcare providers but also survivors, families, and caregivers dealing with aortic dissections or suspecting Marfan syndrome as an underlying cause. In this installment of our Genetics 101 series, we’re learning about Loeys-Dietz syndrome (LDS), another important connective tissue disorder. As always, feel free to reach out to me at ryan@myaorticjourney.com with any questions, and remember the importance of #thinkaortathinkfamily. Also, stay tuned for my next article, where we will discuss Ehlers-Danlos syndrome (EDS), which is a group of related connective tissue disorders.


What is Loeys-Dietz syndrome?

Loeys-Dietz syndrome (LDS) is a rare, hereditary connective tissue disorder that affects the aorta and other body systems.


Few people are misdiagnosed with LDS like we see in Marfan syndrome, in part because it’s much rarer and something most doctors are not very familiar with. Also, historically, LDS was a condition that was known for having very significant features related to the face and skull and major orthopedic differences, so it’s not a term that physicians are just throwing around.


However, we now know that some families with LDS do not have these significant features; in fact, they may have only very subtle features, or none at all (depending upon the gene and/or genetic mutation involved). For this reason, for aortic dissection survivors and their families, understanding LDS is important, especially when it comes to non-classical (less severe) presentations with few related body findings.


In this article, we'll learn about LDS, shedding light on its genetics, symptoms, diagnosis, management, and resources for living with this condition.


Overview of Loeys-Dietz Syndrome

Definition and history:

Loeys-Dietz syndrome is named after Dr. Bart Loeys and Dr. Hal Dietz, the researchers who first described the disorder back in 2005. LDS affects the body's connective tissues, leading to various problems, including aortic aneurysms and dissections (but also aneurysms and dissections of smaller arteries as well).


Comparison to Marfan syndrome and other hereditary thoracic aortic diseases:

While LDS has some similarities to Marfan syndrome, it's a distinct disorder. Both conditions involve connective tissue abnormalities and increased risk of aortic dissection. However, LDS often progresses more rapidly, and affected individuals may have different physical characteristics.


Prevalence and demographic factors:

LDS is a rare disorder, with an estimated prevalence of 1 in 100,000 individuals. It affects people of all ethnic backgrounds and genders.


Genetics of Loeys-Dietz Syndrome:

-Genes associated with LDS

Several genes are implicated in LDS, including TGFBR1, TGFBR2, SMAD2, SMAD3, TGFB2, and TGFB3. These genes play a role in the development and maintenance of connective tissues, particularly in the aorta.

-Inheritance patterns

LDS is typically inherited in an autosomal dominant manner, meaning that a person with the syndrome has a 50% chance of passing it on to each child. Like Marfan syndrome, about 75%, or 3/4 of the time, the condition is inherited from an affected parent. The other 25%, or 1/4 of the time, the condition occurs as the result of a new genetic typo in the child; however, that affected child’s future children would then have a 50/50 chance.

-Genetic testing and counseling options

Genetic testing can help confirm an LDS diagnosis or identify at-risk family members. Genetic counseling can provide essential information and support to individuals and families affected by LDS.


Symptoms and Manifestations of Loeys-Dietz Syndrome:

-Classical presentation of LDS

Major body findings

LDS affects multiple body systems, leading to various symptoms, such as:

• Aortic aneurysms and dissections, but also involving smaller arteries as well

• Arterial tortuosity (twisting or curving of arteries)

• Skeletal abnormalities (pectus, or chest, deformities, scoliosis, joint laxity)

• Craniofacial features (widely spaced eyes, cleft palate, bifid uvula – the thing hanging in the back of the throat looks like it’s split in half, and craniosynostosis, where the bones in the skull fuse together too early, leading to an usual shape of the skull)

• Skin abnormalities (translucent skin, easy bruising)

-LDS can also cause some additional features similar to Marfan, including:

• Tall stature

• Long fingers and toes (arachnodactyly)

• Flat feet (pes planus)

-Non-classical presentations of LDS

Milder or atypical symptoms

Some individuals with LDS may have milder or atypical symptoms, making diagnosis more challenging. For example, they may not exhibit the classical craniofacial or skeletal features but are still at risk for aortic dissections.


Importance of considering LDS in aortic dissection survivors without classical features:

Given the potential for non-classical presentations, it's vital for aortic dissection survivors and their families to consider LDS in their risk assessment, even if they don't exhibit all the typical features.


The genes that cause classical and non-classical forms of LDS should be on aorta genetic testing panels.


Diagnosis and Monitoring of Loeys-Dietz Syndrome:

Diagnostic criteria

Diagnosing LDS involves a combination of clinical evaluation, family history, genetic testing, and imaging studies.


Imaging techniques for detecting and monitoring aortic abnormalities:

Imaging techniques like echocardiograms, CT scans, and MRIs can help detect aortic abnormalities and monitor the progression of LDS.


Regular imaging is essential for early intervention and preventing complications.


Role of a multidisciplinary care team:

Due to the complex nature of LDS, a multidisciplinary care team, including cardiologists, geneticists, and other specialists, is often involved in diagnosis, monitoring, and treatment.


Management and Treatment of Loeys-Dietz Syndrome:

Lifestyle modifications

Individuals with LDS should adopt certain lifestyle modifications to reduce the risk of complications, such as:

• Avoiding high-intensity sports and activities that increase blood pressure or increase the chance of trauma to the chest

• Maintaining a heart-healthy diet

• Refraining from smoking or using tobacco products


Medications to reduce the risk of aortic dissection:

Certain medications, like beta-blockers and angiotensin receptor blockers (ARBs), can help lower blood pressure and possibly reduce the risk of aortic dissection in LDS patients.


Surgical interventions:

Surgery may be necessary to repair or replace an enlarged section of the aorta or to fix other related issues such as orthopedic issues. The decision to perform surgery depends on factors like the size of the aneurysm, the rate of growth, and the patient's overall health. Individuals with LDS have an increased risk of dissection at smaller aneurysm diameters, so proper diagnosis is very important as it relates to the timing of surgery compared to other genetic causes of aortic aneurysm and dissection.


Ongoing monitoring and follow-up care:

Regular monitoring and follow-up care are critical for individuals with LDS to ensure timely interventions and appropriate adjustments to their treatment plans.


Living with Loeys-Dietz Syndrome:

-Emotional and psychological challenges

Living with LDS can be challenging, both physically and emotionally. Patients may experience anxiety, depression, or feelings of isolation. Mental health support is crucial for helping individuals and their families cope with these challenges.


-Support groups and resources for patients and families

Connecting with others who understand the challenges of living with LDS can be beneficial. Support groups, online forums, and patient advocacy organizations can offer valuable resources, information, and emotional support.


-Advocacy and awareness efforts

Raising awareness about LDS and advocating for better resources can help improve the lives of those affected by the condition. Participating in awareness events, fundraising, and sharing personal experiences can make a difference.


Conclusion:


In conclusion, understanding Loeys-Dietz syndrome and other connective tissue disorders is vital for proper diagnosis and management of aortic diseases. By raising awareness and staying informed, we can empower ourselves and our loved ones to make the best decisions for our health. As we continue to explore various genetic conditions related to aortic disease, don't forget to keep an eye out for our next article on Ehlers-Danlos syndrome. If you have any questions or concerns, please feel free to reach out to me at ryan@myaorticjourney.com. Let's continue learning and supporting one another on this journey with the help of Aortic Hope. Remember, #thinkaortathinkfamily!

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