Familial disorder of generalized connective tissue
abnormalities leading to connective tissue weakness with hyperextensible
joints, eyes (dislocation of the lens), increased risk of valvular/aortic
dissection disease, and spontaneous pneumothorax. The leading cause of
mortality in the infancy period is progression from mitral valve prolapse to
regurgitation often in conjunction with tricuspid regurgitation.
Hyperlaxity of the joints (wrist, ankles) and arachnodactyly (finger and
toes) in a newborn with Marfan syndrome.
Characteristic adduction of the thumb and arachnodactyly in the same
child with Marfan syndrome.
First described in 1896 in a 5-year-old girl,
Gabrielle P, by Antoine B. J. Marfan, a French
pediatrician. The girl had disproportionately long
limbs, hands, and feet. Marfan used the term “pattes
d'araignée" (spider's legs) and originally called the
condition “dolichostenomely" (Greek: stenos = narrow;
slender; melos = limb). In 1902, H. Méry and
L. Baboneix confirmed radiologically the skeletal
anomalies. The first person to use the term “Marfan's
syndrome” was Henriculus J. M. Weve of Utrecht in
In the United States, this medical condition affects
about 1:10,000 individuals and possibly as many as 1:3000-5000 individuals.
It is estimated that in 2004 at least 200,000 people had Marfan syndrome.
Internationally, there are no geographic predilections.
Autosomal dominant trait with variable
expression. Approximately 15% of cases occur sporadically. In fewer than
1% of cases, it is autosomal recessive.
Mutations in the gene for fibrillin-1 on
chromosome 15 (15q21.1). Fibrillin is a major component of microfibrils,
which are structural components of the zonular fibers of the lens and
associated with elastic fibers in the aorta and skin. Tensile strength of
collagen is reduced, while its elasticity is increased. Degeneration of
media of the pulmonary artery, aorta, and distal arteries lead to “cystic
medial necrosis” and weakness. Aneurysm formation results. Disproportionate
growth of long bones is present, leading to arachnodactyly with
hyperextensible joints. Emphysema and spontaneous pneumothorax may occur.
The thumb and wrist signs are screening tests for the
joint hypermobility of Marfan syndrome. The former is positive when the
thumb extends well beyond the ulnar border of the hand when overlapped by
fingers and the latter positive when the thumb overlaps the fifth finger as
they grasp the opposite wrist. The definitive diagnosis is made on clinical
grounds; at least two of the four criteria should be present: a positive
family history of the condition, the skeletal, cardiovascular, or ocular
features. There is no diagnostic laboratory test.
In persons younger than 20 years, the prevalence
of serious cardiac complications is low, but aortic root diameter increases
with age and aortic regurgitation and type II dissection are responsible ...