The average adult height among people with dwarfism is 4 feet cm. Many different medical conditions cause dwarfism. In general, the disorders are divided into two broad categories:. Some people prefer the term "short stature" or "little people" rather than "dwarf" or "dwarfism. Short stature disorders do not include familial short stature — short height that's considered a normal variation with normal bone development.
Signs and symptoms — other than short stature — vary considerably across the spectrum of disorders. Most people with dwarfism have disorders that cause disproportionately short stature.
Usually, this means that a person has an average-size trunk and very short limbs, but some people may have a very short trunk and shortened but disproportionately large limbs. In these disorders, the head is disproportionately large compared with the body. Almost all people with disproportionate dwarfism have normal intellectual capacities. Rare exceptions are usually the result of a secondary factor, such as excess fluid around the brain hydrocephalus.
The most common cause of dwarfism is a disorder called achondroplasia, which causes disproportionately short stature. This disorder usually results in the following:. Another cause of disproportionate dwarfism is a rare disorder called spondyloepiphyseal dysplasia congenita SEDC.
Signs may include:. Proportionate dwarfism results from medical conditions present at birth or appearing in early childhood that limit overall growth and development.
So the head, trunk and limbs are all small, but they're proportionate to each other. Because these disorders affect overall growth, many of them result in poor development of one or more body systems. Growth hormone deficiency is a relatively common cause of proportionate dwarfism.
It occurs when the pituitary gland fails to produce an adequate supply of growth hormone, which is essential for normal childhood growth. Signs include:. Signs and symptoms of disproportionate dwarfism are often present at birth or in early infancy. Proportionate dwarfism may not be immediately apparent. See your child's doctor if you have any concerns about your child's growth or overall development.
Most dwarfism-related conditions are genetic disorders, but the causes of some disorders are unknown. Most occurrences of dwarfism result from a random genetic mutation in either the father's sperm or the mother's egg rather than from either parent's complete genetic makeup. About 80 percent of people with achondroplasia are born to parents of average height.
A person with achondroplasia and with two average-size parents received one mutated copy of the gene associated with the disorder and one normal copy of the gene. A person with the disorder may pass along either a mutated or normal copy to his or her own children. Turner syndrome, a condition that affects only girls and women, results when a sex chromosome the X chromosome is missing or partially missing.
Depending on the type of dwarfism, two average-size parents can have a child with short stature. What makes a gene mutate is not yet well understood. The change seems to be random and unpreventable, and can happen in any pregnancy. If parents have some form of dwarfism themselves, the chances are higher that their children also will be little people. A genetic counselor can help determine the likelihood of passing on the condition in these cases.
Does everyone with dwarfism look alike? Not at all. Everyone with dwarfism is short, but different types of dwarfism have different causes and different physical traits. Most types of dwarfism are skeletal dysplasias diss-PLAY-zhee-uhs. There are more than different types of these unusual cartilage and bone growth conditions. In general, dwarfism caused by skeletal dysplasias results in disproportionate short stature.
This means that the limbs and the trunk are not of the same proportion as those of typically statured people. By far the most common skeletal dysplasia is achondroplasia.
This short-limb dwarfism happens in about 1 of every 25, babies born of all races and ethnic groups. People with achondroplasia have a relatively long trunk and shortened upper parts of their arms and legs. This is called rhizomelic shortening. They also may have:. Diastrophic dysplasia is another short-limb dwarfism.
It happens in about 1 in , births. People who have this type tend to have shortened forearms and calves called mesomelic shortening.
They might also have:. Most people with diastrophic dysplasia have joint problems that limit movement. Along with the curved spine, this can make it hard to walk distances, especially when they get older. Some people may need to use crutches, a scooter, or a wheelchair to get around. Spondyloepiphyseal dysplasias SED are short-trunk skeletal dysplasias that involve the spine and the end of the bones that make up the joints epiphyses.
In one type of SED, the short trunk may not be noticed until the child is school age. Other types are seen at birth. Kids with an SED also might:. But most moms do not have these late ultrasounds, so many children with achondroplasia are not diagnosed until after birth. Doctors can diagnose some types of dwarfism earlier in pregnancy. If a child may have dwarfism caused by a skeletal dysplasia, X-rays after birth can see if and how the bones are shaped differently.
Also, doctor sometimes use genetic testing before or after birth to confirm the diagnosis. People with dwarfism can lead healthy, active lives. The conditions that cause dwarfism have their own possible complications, which can change over time. But doctors can treat many of these. People who have this type tend to have shortened forearms and calves called mesomelic shortening.
They might also have:. Most people with diastrophic dysplasia have joint changes that limit movement. People with diastrophic dysplasia often benefit from mobility aids, such as crutches, a scooter, or a wheelchair to get around. Spondyloepiphyseal dysplasias SED are short-trunk skeletal dysplasias that involve the spine and the end of the bones that make up the joints epiphyses.
Along with achondroplasia and diastrophic dysplasia, they're one of the more common types of dwarfism. In one type of SED, the short trunk may not be noticed until the child is school age. Other types are seen at birth. Most pregnant women have a prenatal ultrasound to measure the baby's growth at around 20 weeks. At that stage, features of achondroplasia aren't yet noticeable. Doctors sometimes suspect achondroplasia before birth if an ultrasound late in a pregnancy shows that a baby's arms and legs are shorter than average and the head is larger.
But many children with achondroplasia aren't diagnosed until after birth. Doctors can recognize some other types of skeletal dysplasia earlier in pregnancy. Others aren't noticed until the first few months or years of life, when a child's growth slows. A health care provider may take X-rays after birth to check for bone changes. Doctors also may use genetic testing before or after birth to confirm the diagnosis. Each condition that causes dwarfism has its own possible medical complications, which can change over time.
But doctors can treat many of these. People with dwarfism are cared for by doctors who specialize in orthopedics, neurosurgery, ENT, and pulmonology. Some medical concerns are treated with surgery. These are done with anesthesia, which can be more of a risk for little people because of their smaller body size and airways.
People with dwarfism should try to keep a healthy weight.
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