Molecular Test Listing

Molecular Requisition

Marfan disease is a result of defects in the connective protein fibrillin. It results in individuals that can be very tall and thin, have pectus excavatum (depression under the sternum in chest), and develop cataracts and/or dislocated retinas. Defects in the aorta (mitral valve prolapse, aortic dilation, and aortic aneurysm) can be life threatening - especially for pregnant women. In the United States, it is estimated that 1 in 10,000 are at risk for developing Marfan disease. However, the risk may be much higher because many cases remain undiagnosed due to variable expression.

Most Marfan disease is inherited in an autosomal dominant pattern; the result of a defective fibrillin gene located on chromosome 15. Linkage testing involves tracking the gene through the family using highly polymorphic microsatellite markers surrounding, or within the gene. This approach can be the most informative stratagem for eliminating risk; however, it requires samples from multiple critical family members, including at least two affected individuals.

If multiple affected family members can be clinically identified, linkage testing is the recommended strategy because it is generally faster, less expensive, and can yield the most informative results. To perform linkage testing DNA samples must be obtained on multiple family members. An accurate family history and clinical assessment is essential for correct interpretation of results.

• Individuals with a family history of Marfan disease who want to assess the need for regular echocardiograms.
• Individuals with a family history of Marfan disease who want to assess the risk of high stress physical activity such as competitive sports or pregnancy.
• Individuals with a family history of Marfan disease who wish to undergo prenatal or preconception testing.

• The choice of testing strategy involves many factors. A discussion with the laboratory is recommended before sending a specimen.

•  This approach can be the most informative stratagem for eliminating risk; however, it requires samples from multiple critical family members, including at least two affected individuals. An accurate family history is essential for correct interpretation of results.

• Basic pedigree detailing clinical history.

• Blood EDTA (purple top) tubes:  

            Newborn: minimum 1-2 mL          

            Child/Adult: prefer 2 tubes of 3-5 mL

• Alternate sample: Paraffin block, or 5 unstained sections on slides from the block.

TURNAROUND TIME: 15 working days.

CPT CODES: