Eyes
In Marfan syndrome, the health of the eye can be affected in many ways, but the principal change is partial lens dislocation, where the lens is shifted out of its normal position. This occurs because of weakness in the ciliary zonules, the connective tissue strands which suspend the lens within the eye. The mutations responsible for Marfan syndrome weaken the zonules and cause them to stretch. The inferior zonules are most frequently stretched resulting in the lens shifting upwards and outwards, but it can shift in other directions as well. Nearsightedness (myopia), and blurred vision are common due to connective tissue defects in the eye. Farsightedness can also result particularly if the lens is highly subluxated. Subluxation (partial dislocation) of the lens can be detected clinically in about 60% of people with Marfan syndrome by the use of a slit-lamp biomicroscope. If the lens subluxation is subtle, then imaging with high-resolution ultrasound biomicroscopy might be used.Other signs and symptoms affecting the eye include increased length along an axis of the globe, myopia, corneal flatness, strabismus, exotropia, and esotropia. Those with MFS are also at a high risk for early glaucoma and early cataracts. Cardiovascular system
The most serious signs and symptoms associated with Marfan syndrome involve the cardiovascular system: undue fatigue, shortness of breath, heart palpitations, racing heartbeats, or chest pain radiating to the back, shoulder, or arm. Cold arms, hands, and feet can also be linked to MFS because of inadequate circulation.
Pexidartinib, sold under the brand  name Turalio, is a kinase inhibitor drug for the treatment of adults with symptomatic tenosynovial giant cell tumor (TGCT) associated with severe morbidity or functional limitations and not amenable to improvement with surgery. Pexidartinib blocks the activity of the colony-stimulating factor-1 receptor (CSF-1R). Common side effects are increased lactate dehydrogenase (proteins that helps produce energy in the body), increased aspartate aminotransferase (enzymes that are mostly in the liver but also in muscles), loss of hair color, increased alanine aminotransferase (enzymes that are primarily in the liver and kidney) and increased cholesterol. Additional side effects include neutropenia (low level of white blood cells that help the immune system defend against disease and infection), increased alkaline phosphatase (enzymes that are mostly in the cells of bone and the liver), decreased lymphocytes (white blood cells that help the immune system defend against disease and infection), eye edema (swelling around the eyes), decreased hemoglobin (protein in red blood cells that carry oxygen), rash, dysgeusia (altered sense of taste) and decreased phosphate (electrolytes that help with energy). The US prescribing information for pexidartinib includes a boxed warning about the risk of serious and potentially fatal liver injury.In August 2019, it was approved by U.S. FDA for treatment of giant-cell tumor of the tendon sheath (GC-TS). Pexidartinib is available in the US only through the Turalio Risk Evaluation and Mitigation Strategy (REMS) Program. The U.S. Food and Drug Administration (FDA) considers it to be a first-in-class medication.