欧博娱乐Hitchhiker's Thumb (Distal Hyperextensibi
What causes hitchhiker's thumb?
Many scientists believe hitchhiker’s thumb is an inherited condition, meaning it's passed down from your parents.
In 1953, two researchers performed a study on 450 families. The researchers used a protractor to measure the angles of the study participants’ thumbs. If the participants could bend their thumb joints backward greater than or equal to 50 degrees, they were labeled hitchhiker’s thumbs. As a result of the study, the researchers determined hitchhiker’s thumb is genetic and passed on as a recessive trait, which is explained below.
Your DNA contains genes that determine specific traits, such as your height, weight, skin color and eye color. You receive two genes for each trait from your parents. Each gene contains a specific pattern called an allele. If these alleles are different, the dominant (stronger) gene masks the recessive gene. The dominant gene will take over and you’ll have that trait. If you receive two recessive genes, the recessive gene will take over and you’ll have that trait — in this case, a hitchhiker’s thumb.
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Therefore, if your mother and father both have hitchhiker’s thumb, you should have it too. However, if one of your parents passes on the dominant gene for a straight thumb, and your other parent passes on the recessive gene, you won’t have hitchhiker’s thumb, as the dominant gene masks the recessive one.
What health conditions or disorders are associated with hitchhiker’s thumb?Hitchhiker’s thumb is commonly seen in several genetic conditions and disorders. These include:
What are the symptoms of hitchhiker's thumb?If you have very flexible (hypermobile) thumb joints, you may have hitchhiker’s thumb (distal joint hyperextensibility). Hitchhiker’s thumb could also be a symptom of another condition or disorder, as mentioned above. The symptoms of these conditions include:
ConditionSymptoms
Joint hypermobility syndrome Joint and muscle pain and stiffness; frequent joint and ligament injuries, including dislocations and sprains; thin, stretchy skin.
Diastrophic dysplasia Short stature; very short arms and legs; joint pain and deformities (contractures); abnormal spinal curvature (scoliosis); club foot; cleft palate.
Atelosteogenesis type 2 Very short arms and legs; rounded belly (abdomen); small chest; club foot; cleft palate.
Atelosteogenesis type 3 Underdeveloped bones; very short arms and legs; dislocated joints; wide hands and feet; broad fingers and toes; broad forehead; wide-set eyes; underdeveloped nose; clubfoot; cleft palate.
Condition
Joint hypermobility syndrome
Symptoms
Joint and muscle pain and stiffness; frequent joint and ligament injuries, including dislocations and sprains; thin, stretchy skin.
Diastrophic dysplasia
Symptoms
Short stature; very short arms and legs; joint pain and deformities (contractures); abnormal spinal curvature (scoliosis); club foot; cleft palate.
Atelosteogenesis type 2
Symptoms
Very short arms and legs; rounded belly (abdomen); small chest; club foot; cleft palate.
Atelosteogenesis type 3
Symptoms
Underdeveloped bones; very short arms and legs; dislocated joints; wide hands and feet; broad fingers and toes; broad forehead; wide-set eyes; underdeveloped nose; clubfoot; cleft palate.
If you have any of the above symptoms, you should let your healthcare provider know.