Arachnodactyly is associated with several genetic disorders which impact the connective tissues in the body. Connective tissues provide structure to the body and also have a large role in growth and development. Examples of connective tissues include bones, skin, blood, and muscles.
Because connective tissues are involved in the growth process, genetic disorders that impact connective tissues may result in abnormal growth. In the case of arachnodactyly, certain genetic disorders increase the growth and development of the bones in the fingers and toes, causing them to become very long and thin. The common genetic disorders associated with arachnodactyly include:
Marfan Syndrome
This disorder causes the body to produce defective versions of the protein fibrillin-1, which is involved in the formation of connective tissues. Production of defective fibrillin-1 proteins may result in the abnormal growth and elongation of bones throughout the body, including the bones in the fingers and toes.
hom*ocystinuria is a genetic disorder that leads to the accumulation of hom*ocysteine, an amino-acid, in the body. The accumulation of hom*ocysteine can result in disorders of the connective tissues, leading to the development of very long and thin fingers and toes.
Ehlers-Danlos Syndrome
Ehlers-Danlos syndrome is another genetic disorder that affects the collagen inside the connective tissues throughout the body. Collagen is a protein used to give strength and structure to bones, skin, and other tissues. Collagen is also important for bone growth. Ehlers-Danlos syndrome causes the formation of weak and flexible collagen, which can result in the lengthening of the bones in the fingers and toes.
Additionally, arachnodactyly may occur in a person without any underlying health problems. Some people are just born with very long and thin fingers and toes!
It should be noted that arachnodactyly itself, having long and thin fingers and toes, does not cause any significant health problems. However, the genetic disorders that cause arachnodactyly may cause other abnormalities which may result in significant health problems. For example, Marfan syndrome can also result in the development of an enlarged aorta, which can lead to life-threatening heart problems.
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Arachnodactyly ("spider fingers") is a medical condition that is characterized by fingers and toes that are abnormally long and slender, in comparison to the palm of the hand and arch of the foot.
is a condition with which the fingers and toes are very long and thin, and sometimes curved. This condition sometimes occurs on its own, without an underlying health problem.
Causes. This feature can occur on its own with no underlying health problems, or it can be associated with certain medical conditions, including Marfan syndrome, Ehlers–Danlos syndromes, Loeys–Dietz syndrome, and hom*ocystinuria.
Contractural arachnodactyly resembles Marfan syndrome, but lacks the typical cardiovascular and ocular abnormalities of Marfan syndrome and involves a different fibrillin gene. However, really severe congenital Marfan syndrome may have contractures at birth.
Entire thumb nail protrudes beyond ulnar border of hand. (B) Walker-Murdoch wrist sign. Thumb and fifth finger can overlap around wrist. Both signs must be present to diagnose arachnodactyly according to the Ghent Marfan diagnostic criteria.
They often begin in childhood and can lead to incapacitating scoliosis, pectus deformities, and joint luxations. Skeletal manifestations may result from joint laxity (flat feet, joint hypermobility), long bone overgrowth (tall stature, increased arm span, arachnodactyly), or a combination of both (pectus deformities).
Congenital contractural arachnodactyly (Beals syndrome) is an autosomal dominantly inherited connective tissue disorder characterized by multiple flexion contractures, arachnodactyly, severe kyphoscoliosis, abnormal pinnae and muscular hypoplasia. It is caused by a mutation in FBN2 gene on chromosome 5q23.
Brachydactyly, or abnormally short digits, may result from underdevelopment or absence of some of the phalanges or metacarpals and metatarsals. Long, spidery digits (arachnodactyly) are typical in Marfan's syndrome.
MFS patients often have low self-esteem, lack of self-confidence, and a large percentage of them are introverted (7). One study found that more than 90% of MFS patients surveyed reported that sexual encounters were negatively affected by their disease (29). This can make it difficult for them to build relationships.
Causes. Mutations in the FBN2 gene cause congenital contractural arachnodactyly. The FBN2 gene provides instructions for producing the fibrillin-2 protein. Fibrillin-2 binds to other proteins and molecules to form threadlike filaments called microfibrils.
Arachnodactyly refers to the physical finding of elongated, thin "spider-like" fingers, which are a classic feature of Marfan disease, but by no means pathognomonic 1.
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