MASS syndrome

Overview

MASS syndrome is a connective tissue disorder that shares some features with Marfan syndrome, but is considered a distinct clinical entity. The acronym MASS stands for Mitral valve prolapse, Aortic root diameter at the upper limits of normal, Skeletal features, and Skin involvement. It is an autosomal dominant condition, meaning it is inherited in a pattern where only one copy of the altered gene is sufficient to cause the disorder.

Diagram showing autosomal dominant inheritance.

Clinical Features

Individuals with MASS syndrome may present with a variety of symptoms, which can include:

• Mitral valve prolapse: A condition where the valve between the heart's left atrium and left ventricle doesn't close properly.
• Aortic root diameter: The aorta may be slightly enlarged, but not to the extent seen in Marfan syndrome.
• Skeletal features: These can include a tall stature, long limbs, and arachnodactyly (long, slender fingers).
• Skin involvement: Skin may be hyperextensible and may show striae (stretch marks).

Genetics

MASS syndrome is caused by mutations in the FBN1 gene, which encodes the protein fibrillin-1. This protein is essential for the formation of elastic fibers found in connective tissue. The condition is inherited in an autosomal dominant manner, meaning a single copy of the mutated gene can cause the syndrome.

Diagnosis

Diagnosis of MASS syndrome is primarily clinical, based on the presence of the characteristic features. Genetic testing can confirm mutations in the FBN1 gene, but this is not always necessary for diagnosis.

Management

Management of MASS syndrome involves regular monitoring of the cardiovascular system, particularly the heart valves and aorta. Patients may require echocardiograms to assess the mitral valve and aortic root. Lifestyle modifications and medications may be recommended to manage symptoms and reduce the risk of complications.

Related Conditions

MASS syndrome is related to other connective tissue disorders, such as:

• Marfan syndrome
• Ehlers-Danlos syndrome
• Loeys-Dietz syndrome

Related Pages

• Connective tissue disease
• Mitral valve prolapse
• Aortic aneurysm