Dwarfism

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at March 9, 2016
StartDiseasesDwarfism

Dwarfism is based on how tall a person grows when they are an adult. The general definition of dwarfism is a fully grown adult person being 4 feet 10 inches tall or less. The average height of an adult with dwarfism is about 4 feet.

Contents

Definition & Facts

There are typically two different categories of dwarfism. The first is disproportionate dwarfism which means that the size of the body or body parts are disproportionate to other body parts. Some parts of the body may be small while others are of average size or possibly even above-average size. The head is usually large in size compared to the head. The second is proportionate dwarfism which means that the body is small but all of the body parts are proportionate to the small size of the body.

Symptoms & Complaints

Other than the shorter size, the signs and symptoms of dwarfism vary depending on the disorder that is causing it. There are a number of signs or symptoms that may be seen with disproportionate dwarfism, including:

  • A trunk that is average in size
  • Adult height around 4 feet
  • Legs and arms that are shorter than average
  • Short fingers
  • Swayed lower back that progressively develops
  • Bowed legs that progressively develop
  • Limited elbow mobility
  • A larger than average head
  • A shorter than average trunk
  • Arthritis and issues with movement in joints
  • A short neck
  • Vision problems and hearing problems
  • Hands and feet that are average in size
  • Neck bone instability
  • Rounded, broad chest
  • An out of shape or twisted foot
  • Cheekbones that are slightly flattened
  • Hip deformities that turn thighbones inward

There are also a few signs and symptoms that are seen with proportionate dwarfism, including:

  • Slower than expected growth rate
  • Height when charted on pediatric growth charts that are below the third percentile
  • Sexual development that is delayed in the teenage years, or there is no sexual development in that time

Causes

Most of the conditions that cause dwarfism are genetic disorders, but the cause of some of the disorders are not known. Most of the time dwarfism occurs because of a genetic mutation in either the mother's egg or the father's sperm. The most common disorders that cause dwarfism are:

  • Achondroplasia - Of all of the people that are born with achondroplasia, which is a disorder that causes dwarfism, 80 percent of them are born to two people that are of average height. Those that are born to two people of average height got the mutated gene from one of their parents and a normal gene from the other parent. A person with achondroplasia could either pass the mutated gene or a normal gene onto their own children.
  • Turner syndrome - This is a condition that only affects females. When a female is conceived, they are given an X chromosome (a sex chromosome) from each of their parents. In someone that has Turner syndrome, one of the X chromosomes is either missing or is partially missing.
  • Deficiency of growth hormone - When someone has a growth hormone deficiency, it may be traced back to an injury or a genetic mutation, but most of the time no cause for the deficiency can be found.
  • Other causes of dwarfism can come from other genetic disorders, poor nutrition, or other hormone deficiencies. But there are also some cases where the cause of dwarfism is unknown.

Diagnosis & Tests

There are a number of factors that a pediatrician will examine in order to access the growth of a child which will help to determine whether or not the child has a disorder related to dwarfism. The tests may include:

  • Measurements - As part of a regular checkup for a child, measurements of the child's weight, height, and head circumference will be taken. These measurements will then be plotted on a chart in order to show their percentile for each. It is important for the pediatrician to do this in order to find any abnormalities in a child's growth, such as an unusually large head or growth that is delayed. If any abnormalities are found, the pediatrician will likely want to take measurements more often.
  • Appearance - Several of the disorders that cause dwarfism also come with skeletal and facial features that are quite distinct. A pediatrician may use a child's appearance to help determine if they have dwarfism.
  • Imaging Technology - The doctor may also decide to have X-rays done in order to determine if there are any abnormalities of the skeleton or skull. An MRI may also be used in order to determine if there are any abnormalities of the hypothalamus or pituitary gland which both play a part in hormone function.
  • Genetic testing - There are genetic tests available that may be used as well. These tests will show whether the child has any of the genetic disorders that often cause dwarfism. Most of the time these tests will not be used because the diagnosis can be made in other ways.
  • Family history - A pediatrician may ask for the history of a family in order to determine if short stature runs in the family.
  • Hormone tests - Hormone tests may be ordered to determine whether the level of growth hormones and other hormones are at the levels they should be for normal growth.

Treatment & Therapy

Most of the treatment that is used for dwarfism does not increase the height of the person but are used to help with complications that come with it. Surgical treatments may be used for people with disproportionate dwarfism in order to help with these issues:

  • Correct bones growing in the wrong direction
  • Correct and stabilize the shape of the spine
  • Alleviate spinal cord pressure
  • If excess fluid occurs on the brain, a shunt will be placed to remove the fluid

A procedure in order to lengthen limbs may be done as well. This is not something that is done in all cases, but some will choose to have it done. For those that have dwarfism due to a growth hormone deficiency, hormone therapy may be used as a treatment.

Prevention & Prophylaxis

There are no medical ways to prevent dwarfism.

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