MASS Phenotype

MASS Phenotype is a connective tissue disorder that is similar to Marfan Syndrome. It is caused by a similar mutation in the gene called fibrillin-1 that tells the body how to make an important protein found in connective tissue. As with Marfan Syndrome, there is a 50 percent chance of passing the gene along to each child when a parent has MASS Phenotype.

A person that exhibits features of MASS Phenotype should consult with a doctor capable of making a diagnosis, regarding this particular type of connective tissue disorder. Often times such a doctor will be a medical geneticist. It is of utmost importance that a person with MASS Phenotype receive an early and accurate diagnosis so the correct treatment begin.

MASS stands for the Mitral valve, Aorta, Skin and Skeletal features of the disorder. MASS Phenotype affects different people in various different ways.

In MASS Phenotype:

Mitral valve prolapse may be present. This is when flaps of one of the heart’s valves (the mitral valve, which regulates blood flow on the left side of the heart) are “floppy” and don’t close tightly.

Aortic roots diameter may be at the upper limits of normal for the body size, but unlike Marfan Syndrome there is not progression to aneurysm or predisposition to dissection.

Skin may show stretch marks that are not related to weight gain or loss (striae).

Skeletal feature, including curvature of the spine (scoliosis), chest wall deformities, and joint hypermobility, may be present in certain people with the disorder.

MASS Phenotype does not involve the eyes (lens dislocation).

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