Cystic medial necrosis
Encyclopedia
Familial thoracic aortic aneurysm (also referred to as familial aortic dissection or cystic medial necrosis of aorta) is an autosomal dominant disorder of large arteries.
There is an association between familial thoracic aortic aneurysm and Marfan syndrome
as well as other hereditary connective tissue disorders.
, elastin
, and smooth muscle
caused by aging contribute to weakening of the wall of the artery.
In the aorta, this can result in the formation of a fusiform aneurysm
. There is also increased risk of aortic dissection
.
.
The term "cystic medial degeneration" is sometimes used instead of "cystic medial necrosis", because necrosis
is not always found.
There is an association between familial thoracic aortic aneurysm and Marfan syndrome
Marfan syndrome
Marfan syndrome is a genetic disorder of the connective tissue. People with Marfan's tend to be unusually tall, with long limbs and long, thin fingers....
as well as other hereditary connective tissue disorders.
Presentation
A degenerative breakdown of collagenCollagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...
, elastin
Elastin
Elastin is a protein in connective tissue that is elastic and allows many tissues in the body to resume their shape after stretching or contracting. Elastin helps skin to return to its original position when it is poked or pinched. Elastin is also an important load-bearing tissue in the bodies of...
, and smooth muscle
Smooth muscle
Smooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by...
caused by aging contribute to weakening of the wall of the artery.
In the aorta, this can result in the formation of a fusiform aneurysm
Aneurysm
An aneurysm or aneurism is a localized, blood-filled balloon-like bulge in the wall of a blood vessel. Aneurysms can commonly occur in arteries at the base of the brain and an aortic aneurysm occurs in the main artery carrying blood from the left ventricle of the heart...
. There is also increased risk of aortic dissection
Aortic dissection
Aortic dissection occurs when a tear in the inner wall of the aorta causes blood to flow between the layers of the wall of the aorta and force the layers apart. The dissection typically extends anterograde, but can extend retrograde from the site of the intimal tear. Aortic dissection is a medical...
.
Genetics
Types include:| Type | OMIM | Gene | Locus |
|---|---|---|---|
| AAT1 | 11q23.3-q24 | ||
| AAT4 | MYH11 MYH11 Myosin-11 is a protein that in humans is encoded by the MYH11 gene.- Function :Myosin-11 is a smooth muscle myosin belonging to the myosin heavy chain family... |
16p | |
| AAT6 | ACTA2 ACTA2 Alpha-actin-2 also known as actin, aortic smooth muscle or alpha smooth muscle actin is a protein that in humans is encoded by the ACTA2 gene located on 10q22-q24.... |
10q |
Terminology
It is sometimes called "Erdheim cystic medial necrosis of aorta", after Jakob ErdheimJakob Erdheim
Jakob Erdheim was a pathologist.He is credited with the characterization of Erdheim–Chester disease and cystic medial necrosis.-External links:...
.
The term "cystic medial degeneration" is sometimes used instead of "cystic medial necrosis", because necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
is not always found.