Dwarfism is generally defined as an adult height of 4 feet 10 inches centimeters or less. 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. This is probably what happened:. As you can see, you got a blue rectangle from each of your parents. In this case, you have no chance of passing on the dwarfism FGFR3 gene to your child. The orange rectangle was left with your dad.
To summarize, you only need one copy of a dominant gene, like the version of FGFR3 that leads to dwarfism, to show a dominant trait.
Now having said this, it is important to mention that sometimes a child ends up with dominant dwarfism even if neither parent has it. Click here to learn how this happens.
But if this were to happen to you, it would have nothing to do with your father. To end up with recessive dwarfism, your child would have to get a dwarfism gene version from you and your partner.
This is not very likely. This means your dad gave you one of these versions since that is the only version he has! You must have one gene copy leading to dwarfism and one gene copy leading to average height.
You are a carrier for dwarfism. So your dad has two copies of the pink rectangle and your mom has two copies of the blue. You got one from each parent and so have a pink and a blue. You have one gene that can cause dwarfism and on that does not. He or she needs to get a version that leads to dwarfism from mom too. So in the recessive case, passing on dwarfism to your child requires teamwork — both parents must give them a copy. Your child can inherit dwarfism from your father only if their other parent also gives them a dwarfism gene copy.
The odds of this happening are pretty small. First off, your partner would have to be a carrier like you. And even if she were a carrier, then the two of you would both have to pass the version that leads to dwarfism to the same child. Not zero, but very small. Keep in mind again, though, that the recessive form is pretty rare.
Most cases of dwarfism are dominant. And if that is the form your dad has, then you do not have it in your DNA…you cannot pass his dwarfism gene to your kids. If neither of your parents has dwarfism, you cannot inherit the most common form of dwarfism from your grandparent.
The pregnancy may go to full term, but the baby is usually much smaller than average. The result is typically proportional dwarfism. Dwarfism is usually the result of a genetic mutation.
But having a gene or genes responsible for dwarfism can occur in a couple of ways. In some cases, it can happen spontaneously. You may not be born with mutated genes inherited from a parent.
Instead, a mutation of your genes happens on its own — usually without a cause doctors can discover. Inherited genetic disorders can take two forms. One is recessive, which means you inherit two mutated genes one from each parent to have the condition. The other is dominant. You only need one mutated gene — from either parent — to have the disorder.
Other risk factors for dwarfism include a hormone deficiency or malnutrition. Serious malnutrition, which leads to weak bones and muscles, can also be overcome in many cases with a healthy, more nutrient-rich diet.
At birth, sometimes the appearance of a newborn may be enough to make a diagnosis of dwarfism. As part of baby wellness exams, your child should be measured and weighed to see how they compare to the population averages for a child their age. Consistently measuring in the lowest quartiles on the standard growth chart is another sign a pediatrician can use to diagnose dwarfism.
Making a tentative prenatal diagnosis while the baby is still in the womb can be done with an ultrasound. This is a lab test of amniotic fluid from the womb. Genetic testing may be helpful in some cases. This is particularly true when distinguishing one potential cause of dwarfism from another.
A blood test to check for growth hormone levels may also help confirm a diagnosis of dwarfism caused by hormone deficiency. Dwarfism is often accompanied by health complications.
These range from leg and back problems to brain and lung function issues. Pregnancy in those with dwarfism can present its own set of potential complications, including respiratory problems. For some people with proportionate dwarfism, poor development of the organs can lead to significant health problems. For people with growth hormone deficiency, injections of synthetic human growth hormone may be helpful.
This may be done if there are concerns about full adult maturation and sufficient muscle and fat. Estrogen therapy may be necessary until a woman reaches the age of menopause.
For others with dwarfism, surgical treatments may be necessary and helpful to living a longer, healthier life. Another surgical procedure for people with excess fluid around the brain is to place a type of tube, called a shunt , in the brain. This can relieve some of that fluid and reduce pressure on the brain.
Physical therapy and orthotics are noninvasive solutions to some complications of dwarfism. Physical therapy is often prescribed after limb or back surgery to help you regain or improve your range of motion and strength.
Orthotics are custom-made devices that fit into your shoes to help improve your foot health and function. If dwarfism is affecting your balance, how you walk, or other aspects of foot function, talk with a podiatrist about how orthotics may help you. Dealing with prejudices and ignorance in society can be difficult.
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