Marfan syndrome is a multisystem genetic disorder of connective tissue affecting the skeletal, cardiovascular, ocular, pulmonary, and integumentary systems. This paper examines the diagnostic challenges inherent in identifying Marfan syndrome, including the evolution from Berlin to Ghent diagnostic criteria, the complexity of clinical presentations across multiple organ systems, the high costs of genetic testing, and the difficulty in distinguishing Marfan syndrome from phenotypically similar conditions such as MASS syndrome and Stickler syndrome. The paper emphasizes the necessity of a multidisciplinary approach and highlights both advances and limitations in molecular biology testing in achieving accurate diagnosis.
Marfan syndrome is a genetic disorder of connective tissue that is inherited as an autosomal dominant disease. The spectrum of this multisystem disease mainly, but not exclusively, affects the musculoskeletal, ocular, and cardiovascular systems.
The disease is a fibrillinopathy that results from defective synthesis of fibrillin-1. The gene coding for this protein, FBN1, was localized to chromosome 15q21 in humans. However, another gene, MSF2, located at chromosome 3p25, has also been implicated.
Marfan syndrome affects approximately 1 in 5,000 individuals. In the United States, it is estimated that at least 200,000 people suffer from Marfan syndrome or related connective tissue disorders, making it one of the most common single-gene disorders. The disease shows no geographical distribution and affects people of all races and ethnicities.
The earliest documented case of this disease dates to 1896, when pediatric professor Antoine Marfan presented the case of a 5-year-old girl, Gabrielle P., to the Société Médicale des Hôpitaux de Paris. The child had conspicuous abnormalities of her skeletal system that developed throughout her life until her death, probably from tuberculosis. However, it cannot be definitively proven whether Gabrielle suffered from Marfan syndrome; she may have had congenital contractual arachnodactyl instead.
During the 20th century, further phenotypical manifestations of Marfan syndrome were discovered. Ectopia lentis was documented in 1914, autosomal dominant inheritance in 1931, aortic dissection involvement in 1943, aortic dilatation in 1943, mitral valve prolapse involvement in 1975, and dural ectasia in 1988. The gene associated with Marfan syndrome was identified by Francesco Ramirez in 1991 at Mount Sinai Medical Centre in New York.
Until recently, diagnosis of Marfan syndrome relied on clinical criteria developed in 1986 in Berlin, known as the Berlin Nosology or Berlin Criteria. Because the Berlin Criteria did not incorporate molecular data and led to misdiagnosis of unaffected relatives, a new set of criteria, the Ghent criteria, was devised in 1995. Diagnosis of Marfan syndrome continues to evolve, with existing criteria undergoing constant revision based on a 2007 workshop in Brussels, Belgium. This paper examines the diagnostic challenges of Marfan syndrome.
Marfan syndrome is a multisystem disease affecting the skeletal, cardiovascular, ocular, pulmonary, and skin and integumentary systems.
The skeletal system involvement presents with disproportion of the limbs and digits, a condition scientifically known as dolichostenomelia. This is marked by the concomitant underdevelopment of muscle and fat. Patients characteristically appear very tall and thin with broad arms. Abnormalities of limb length are measured as a ratio of the upper segment to the lower segment. The lower segment is measured from the floor to the top of the symphysis pubis, while the upper segment is obtained by subtracting the lower segment from total height. In the normal adult population, this ratio is 0.93; however, in a patient with Marfan syndrome, it is 0.85.
Arachnodactyl, or spider-like fingers, is another salient skeletal feature. Clinically, this is assessed by the Walker-Murdoch thumb sign, in which the index finger and thumb encircle the contralateral wrist with overlap of the distal phalanges. Deformities of the anterior chest, commonly known as pectus excavatum or funnel-shaped chest, may occur. Conversely, pectus carinatum, or protrusion of the chest, may also present. Hypermobility of joints is common, often exaggerated in the arms and presenting as flat feet. Spinal scoliosis greater than 20 degrees, or sideways curvature of the vertebral column, is another skeletal manifestation. This is often complex and characterized by the disappearance of dorsal kyphosis, leading to a flat back. Asymptomatic basilar impressions, atlantoaxial subluxation, and lumbar spondylolisthesis may also occur.
Craniofacial abnormalities include malar hypoplasia, anteroposterior axis dolichocephaly, and micrognathia. Clinical assessment of the mouth often reveals an arched palate, crowding of teeth, and extreme maxillary overjet. Approximately 70 percent of patients require orthodontic treatment. Protrusio acetabuli, or protrusion of the acetabulum, is also present—a malpresentation of the hip joint where the medial wall of the acetabulum invades the pelvic cavity, with associated medial displacement of the femoral head. This is assessed using radiography and affects 31 to 100 percent of patients to varying degrees. Clinical presentations include hip joint stiffness, gradual limitation in activity related to joint pain, a waddling gait, restricted range of motion, flexion contracture, pelvic tilt leading to hyperlordosis of the lumbar spine, and osteoarthritic changes. The consequence is early hip pain and osteoarthritis.
Neuromeningeal involvement in the form of dural ectasia, or dilation of the dural sac, is not strictly a skeletal manifestation. However, its ramifications primarily affect the spine, often leading to lumbar scalloping. Approximately 92 percent of patients were found to have dural ectasia. Magnetic resonance imaging and CT scans demonstrated high sensitivity and specificity in its diagnosis.
Cardiovascular system involvement is the most serious complication of Marfan syndrome. It presents with dilation of the aortic root, involving enlargement of the sinuses of Valsalva, with a prevalence of approximately 70 to 80 percent. The major life-threatening complications are aortic root dilatation and aortic dissection. One-third of patients have prolapse of the mitral valve, mitral enlargement of the aortic root, or a combination of both on echocardiography, despite normal auscultatory findings on clinical examination. Manifestation occurs at an early age and is more common in men than in women. Other features include dilation of the main pulmonary artery and the descending abdominal aorta, calcification of the mitral annulus, and a higher prevalence of ventricular and supraventricular arrhythmias compared to the general population.
The major ocular presentation is ectopia lentis, a subluxation or malposition of the lens. The lens is typically displaced in a superotemporal direction. Presentation may occur at birth or develop during childhood or adolescence. Other manifestations include a flat cornea, increased axial length of the globe, cataract formation or opacification of the lens, retinal detachment, myopia, and glaucoma or increased intraocular pressure.
Involvement of the skin and integumentary system is manifested as striae atrophicae, or stretch marks, in the absence of weight gain. Manifestations of the pulmonary system include spontaneous pneumothorax and multiple pneumonic blebs found on chest radiograph.
The clinical diagnosis of Marfan syndrome has progressively changed throughout the years. Both clinical criteria and molecular criteria are used in correct diagnosis. The first diagnostic tool was the Berlin Nosology or Criteria, established during the 7th International Conference on Human Genetics workshop held in Berlin. It was composed of major criteria—features not commonly found in the general population and therefore carrying significant diagnostic weight—and minor criteria, which were common in the general population and could be confused with mimicking conditions.
The Berlin Nosology required, in the absence of an unequivocally affected first-degree relative, involvement of the skeleton and at least 2 other systems with a minimum of 1 major manifestation (ectopia lentis, aortic dilatation, or dural ectasia). In the presence of an affected first-degree relative, only 2 organ systems needed to be involved. The Berlin Nosology included 6 systems: skeletal, cardiovascular, ocular, pulmonary, skin and integumentary, and central nervous systems. Only 2 major criteria existed: ectopia of the lens in the ocular system and aortic dilation or aortic dissection in the cardiovascular system. Other criteria were classified as minor across the six systems.
As time progressed, weaknesses in the Berlin Nosology became evident, particularly with the advancement of molecular biology testing. Subsequently, a group of clinicians met in Ghent, Belgium, and developed the current diagnostic criteria, the Ghent Nosology. Like the Berlin Nosology, the Ghent criteria was based on clinical findings in various organ systems and the nature of family history. A major criterion was classified as having high diagnostic specificity because it was less frequent in other conditions and the general population. A significant departure from the Berlin Nosology was the conversion of minor criteria in the skeletal system into major criteria.
For diagnosis under the Ghent Nosology, a patient must have a first-degree relative diagnosed with the disease, plus involvement of two systems with one having a major sign. In the absence of a family history or genetic criteria, three systems must be involved, with two showing major signs. The Ghent Nosology divided conditions into seven systems: skeletal, ocular, cardiovascular, pulmonary, cutaneous, dura mater, and genetic. Major clinical signs include pectus carinatum or pectus excavatum requiring surgery, upper segment to lower segment or arm span ratio greater than 0.5, wrist or thumb sign, scoliosis greater than 20 degrees or spondylolisthesis, acetabulum protrusion, flat feet, and elbow extension less than 170 degrees. Lumbosacral ectasia was included as a major criterion in the dura mater system. A direct parent meeting diagnostic criteria, a mutation of the FBN1 gene known to cause Marfan syndrome, or a genetic marker close to FBN1 and transmitted with disease in the family is also regarded as a major criterion.
For system involvement, more stringent measures apply. The skeletal system is involved if at least four major clinical signs are present. The ocular system is involved with at least 2 minor signs. The cardiovascular, pulmonary, and cutaneous systems are involved if at least one minor sign is present. The dura mater is involved if at least one major sign is present.
Several conditions present clinically similar to Marfan syndrome, creating diagnostic difficulty. For instance, MASS syndrome presents with mitral valve prolapse, where the mitral valve does not close properly but allows blood to regurgitate into the heart during ventricular contraction. The diameter of the aortic root may be at the upper limit of normal; however, there is no progression to an aneurysm nor development of aortic dissection. The disease presents with stretch marks unrelated to weight gain and skeletal features of Marfan syndrome like scoliosis and joint hypermobility. MASS syndrome is a connective tissue disorder inherited in an autosomal dominant pattern and associated with mutations of the FBN1 gene. However, patients with MASS syndrome never develop dislocation of the lens or aortic root enlargement.
Stickler syndrome, or hereditary arthro-ophthalmopathy, is also a multisystem disorder requiring eye, craniofacial, and another system to be affected. Salient features include myopia, degeneration of the retina and vitreous, retinal detachment, deafness, arthropathies, hypermobility of joints, facial hypoplasia, and micrognathia. Most of these features are shared with Marfan syndrome. In Shprintzen-Goldberg syndrome, skeletal changes are suggestive of Marfan syndrome; however, these patients have craniosynostosis and neurodevelopmental abnormalities, and aortic dilatation may be present. Other mimicking conditions include congenital contractual arachnodactyl, familial aortic dissection, familial ectopic lentis, and familial Marfan-like habitus.
All patients with Marfan syndrome should have their physical activity restricted and receive prophylaxis for endocarditis. They should undergo annual echocardiography and receive treatment with beta-blocking agents. The mainstay of cardiovascular management is beta-blockers, discovered in the early 1970s to reduce the incidence of aortic dissection. Beta-blockers retard aortic growth in both children and adults. In children, annual echocardiography is recommended. When the aortic root diameter exceeds 5 centimeters, prophylactic surgery is highly recommended, with greatly improved success rates and minimal mortality. Angiotensin-converting enzyme inhibitors have also been found to improve outcomes by reducing central arterial pressures and aortic stiffness. Progesterone and estrogen therapy has been found to reduce patient height if therapy begins before puberty.
Patients with Marfan syndrome may also require orthopedic surgery, ophthalmic surgery, pneumothorax treatment, genetic counseling, and psychiatric evaluation.
Diagnosis of Marfan syndrome is challenging and requires a multidisciplinary approach involving an orthopedic specialist, cardiologist, ophthalmologist, geneticist, radiographer, and specialist nurse. Engaging this range of specialists can be costly for patients with Marfan syndrome.
"Beta-blockers, surgery, multidisciplinary management"
The progressive appearance of symptoms over time makes diagnosis difficult. All features do not appear simultaneously; they evolve over time from childhood through adolescence.
In some countries or clinical settings, either the Ghent criteria or the Berlin Nosology is still employed for diagnosis. Prior to advances in molecular biology, diagnosis depended on the Berlin Nosology. However, this criteria was not strict and sometimes led to overdiagnosis. This was emphasized in a study showing that 19 percent of patients diagnosed under the Berlin Nosology failed to meet the Ghent nosology criteria. The same study revealed that dural ectasia was the second most common major diagnostic manifestation, with screening establishing Marfan diagnosis in 23 percent of patients under the Ghent Nosology.
The Berlin Nosology encouraged diagnosis using non-specific criteria once Marfan was diagnosed in a first-degree relative; in this scenario, only identification of a trait seen in two organ systems was required. This created problems of overdiagnosis and misdiagnosis. The Ghent criteria are more stringent, requiring, in addition to family history, a major clinical manifestation and involvement of a second system for definitive diagnosis.
Although the Ghent criteria aims to be as objective as possible, several shortcomings exist. Most manifestations are age-related, and some are difficult to quantify. Additionally, few studies have tested the sensitivity and specificity of Marfan syndrome anomalies. For example, the association between dural ectasia and Marfan syndrome was only recently established, and little is known about its prevalence; further studies are needed to qualify this presentation as a major criterion.
There are also psychological issues faced by those labeled with Marfan syndrome. Patients may feel like social misfits, adding financial stress to their treatment burden. Correct and proper diagnosis is therefore essential.
Patients diagnosed with Marfan syndrome face numerous diagnostic challenges, from management costs to involvement of several specialists. There are also conditions that mimic, resemble, or are closely related to Marfan syndrome. However, since the improvement of molecular biology techniques in the late 20th century, diagnostic accuracy has greatly improved, though it remains imperfect. Some countries have established specialist centers or clinics specifically to deal with Marfan syndrome, such as the Stanford University Marfan Centre, representing a significant step in the right direction.
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