Marfan syndrome is a genetic condition affecting the body’s connective tissues. Because the condition makes them weaker and less flexible, it can impact various systems, including the skeleton, heart, blood vessels, and eyes. The signs and symptoms can differ significantly from one person to another, even within the same family, as some individuals may have mild effects while others develop more serious complications.
Characteristic Facial Features in Females with Marfan Syndrome
The influence of Marfan syndrome on connective tissue often results in a distinct facial appearance. A common characteristic is a long, narrow face, a feature referred to as dolichocephaly. This elongated facial structure can be one of the first observable signs.
This facial structure is often accompanied by several other recognizable traits. The eyes may appear deep-set, a condition known as enophthalmos, giving them a sunken appearance. Additionally, the palpebral fissures, or the openings between the eyelids, often slant downwards at the outer corners.
Other structural characteristics can include underdeveloped cheekbones, referred to as malar hypoplasia, which contributes to a flatter look in the midface area. The lower jaw, or mandible, may also be smaller than average and set back, a feature called micrognathia or retrognathia. These features do not appear differently between males and females.
Significant Ocular and Dental Signs
Marfan syndrome presents specific clinical signs within the eyes and mouth that are important for its identification. A primary hallmark of the condition is the dislocation of the eye’s lens, known as ectopia lentis. This occurs in more than half of people with the syndrome because the connective tissues holding the lens in place are too weak, leading to vision problems like severe nearsightedness and astigmatism.
Another common finding is a high, arched palate, which is the roof of the mouth. The altered structure of the connective tissue affects the palate’s development, making it unusually high and narrow. This shape directly impacts the available space for teeth, often leading to significant dental crowding.
The ocular system can also be affected by an increased risk for other conditions like glaucoma, where pressure inside the eye increases, and the early development of cataracts. Another serious concern is retinal detachment, where the light-sensitive tissue at the back of the eye pulls away from its blood supply.
The Genetic Cause of Marfan Syndrome’s Physical Traits
The underlying reason for the physical characteristics seen in Marfan syndrome is a mutation in the FBN1 gene. This gene holds the instructions for producing a protein named fibrillin-1. Fibrillin-1 is a fundamental component of microfibrils, which are structures that form the foundation of connective tissue.
These fibrillin microfibrils provide strength and elasticity to tissues. When a mutation occurs in the FBN1 gene, the body either produces less fibrillin-1 or the protein that is produced is abnormal and cannot function correctly. This leads to weakened connective tissue that cannot properly support various body structures.
The deficiency in functional fibrillin-1 directly causes the traits associated with the syndrome. For instance, the lack of tissue integrity allows for the overgrowth of long bones, resulting in tall stature and long limbs. It also affects the development of the facial bones, leading to the elongated face, and contributes to the instability of the eye’s lens.
The Process of Diagnosis
Confirming a diagnosis of Marfan syndrome involves a thorough evaluation by a medical team. The process begins with a physical examination to look for the characteristic signs of the disorder. A doctor will also take a comprehensive medical and family history, as the condition is often inherited.
To formalize the diagnosis, clinicians use a specific set of guidelines known as the Ghent nosology. These criteria, which were updated in 2010, place significant weight on two cardinal features: aortic root aneurysm and dislocation of the lens (ectopia lentis).
A team of specialists is often involved in the diagnostic process because the syndrome affects multiple body systems. This team may include a cardiologist to assess the heart and aorta with an echocardiogram, an ophthalmologist for a detailed eye exam, and an orthopedist to evaluate the skeletal system. A geneticist may also be consulted, and a genetic test for mutations in the FBN1 gene can help confirm the diagnosis.