As mentioned above, Marfan Syndrome is a genetic disorder. An alteration (mutation) of the Fibrillin-1 (FBN-1) gene causes a defect in the microfibrils (structural component of connective tissue) and weakening of the elastic fibers, which manifests itself mainly in the organ systems of the heart, skeleton, eye and vessels. Autosomal dominant inheritance means that an autosomal, i.e. not sex-linked chromosome is involved.
The human chromosome set consists of 23 pairs of chromosomes. Of these, 22 pairs are autosomes (chromosome 1-22) and 1 pair are sex chromosomes (X and Y). Dominant means that a genetic change (mutation) in a gene on one of the two chromosomes of a pair of chromosomes leads to the disease, although the other one is not pathologically altered.
If one parent is affected by the disease, there is a 50% probability that the child will also fall ill. The severity of the disease is highly variable and can range from severe neonatal Marfan syndrome, which shows considerable symptoms even at birth, to symptomless disease. But even if neither parent is affected by the disease, Marfan syndrome can occur in a child.
This is due to new mutations, i.e. spontaneous changes in the fibrillin gene, which are the cause of the disease in 25% of cases. Since the connective tissue throughout the body is affected in this disease, the symptoms of Marfan syndrome vary from individual to individual. The most common and noticeable symptoms are the great length of the body, overlong limbs, changes in visual acuity, heart valve defects and pathological changes in the large blood vessels. For more details, please refer to the criteria of Gent Nosology under the topic Marfan Syndrome Diagnostics.
