Dwarfism is a condition where children are of short stature, ranging to an adult height of between 2 feet 8 inches to 4 feet ten inches. Also known as skeletal dysplasia, it can be caused by over 150 disorders where a child’s bones do not grow in the usual way.
Dwarfism caused by the genetic mutation, a change in the egg or sperm cells prior to conception. It affects the ability of a child’s bones to grow to an average length and the bones are frequently short and crooked, especially in their arms, legs or trunk which may be shorter than the rest of their body.
There are many reasons why children are shorter than their peers, and some factors include:
- Short parents
- A lack of hormones that control growth
- A recurring disease affecting the child’s kidneys, heart or intestines
- A digestive or nutritional problem stopping calcium and vitamin D from functioning properly in a child’s body and promoting growth
There are three basic types of dwarfism:
Achondroplasia: This is the most common type of dwarfism, and children with this type do not convert cartilage to bone during their growing period, especially in the long bones of the arms and legs. Children with this type of dwarfism have a normal size torso, but noticeably shorter arms and legs, and a larger head and distinct forehead. As adults, they can develop a sway in their lower back and bowed legs. The average height for an adult is 4’1” for women and 4’2” for men.
Diastrophic Dysplasia: Children with diastrophic dysplasia have an abnormal cartilage structure preventing the proper formation of their bones. Children with this type of disorder have short calves and forearms and a progressive curvature of the spine. Sometimes they can have an inward or downward pointing of the foot, known as clubfoot. Patient with this type of dysplasia have limited movement due to the joint deformities and can make it difficult to walk, possibly requiring the use of crutches or a wheelchair as they age.
Spondyloepiphyseal Dysplasia: This is a rare genetic disorder that affects bone growth and is commonly known as SED. Children with SED have a problem with how the type II collagen gene assembles, interfering with normal bone development and connective tissue. Patients with this disorder have short limbs, neck and torso but average-sized feet and hands as well as a curvature of the spine that can result in respiratory problems and spinal cord damage. SED patients may develop limited joint mobility and arthritis early in their life.
Symptoms of Dwarfism
Children with dwarfism are far below the average height for their age, and may not experience full motion in their joints. Some symptoms that may indicate this disorder are:
- A disproportionately large head with a prominent forehead and flattened bridge of the nose
- Bowlegs or knock-knees, protruding inward
- Children are not growing as quickly as their peers
- Delayed growth
- Limited mobility at the elbows
- Short fingers
- Wide or web-like neck
Doctors are usually able to diagnose achondroplasia before a baby is born through an ultrasound in the latter part of pregnancy. The ultrasound will show if a baby’s arms and legs are shorter than average of their head is larger.
Other types of dwarfism or bone dysplasias may not be able to be diagnosed until after a baby is born and can be tested through the following:
Appearance: Because dwarfism has many distinct facial and skeletal features, your child’s appearance may help your doctor in making a diagnosis.
Family History: Your doctor may take a stature history in grandparents, parents and siblings to help determine the average range of height in your family and if short stature is present.
Genetic Testing: Genetic tests are used to diagnose many types of dwarfism-related disorders. Your doctor may suggest genetic testing if they are not clear about the type of dwarfism your child may have. This is done through tests that assess the condition of X chromosomes from the blood cells.
Hormone Testing: Another way to diagnose dwarfism is to assess levels of growth hormones or other hormones that are essential for your child’s growth and development.
Imaging Technology: To determine the type of dwarfism your child may have, your doctor may order an X-ray of your child’s skull or skeleton. MRIs (magnetic resonance imaging) can also reveal any abnormalities of the pituitary gland or a section of the brain that play a role in the function of hormones.
Measurements: During well-baby examinations measurements of your child’s head circumference, weight and height are taken and compared against the percentile ranking and expected future growth. If there are any trends in your child’s measurements, more can be taken over a specific period of time to determine if they have dwarfism.
Treatments for Dwarfism:
Most treatments for dwarfism do not increase stature but can possibly reduce problems or complications that your child may have or experience as they become an adult.
Some of the treatments may include:
Surgery: Various surgeries may be necessary to correct bone direction and involves inserting metal staples into the ends of long bones; dividing limb bones; inserting rods or staples to help correct the shape of the spine or increasing the size of the bone openings in the spine to eliminate pressure on the spinal cord.
Limb Lengthening: The Shriners Hospitals for Children® can treat dwarfism through limb lengthening surgery where a long bone is divided into two or more sections by the surgeon. These sections are slightly separated and the bone and limb, arm or leg, is braced with a metal frame. Pins and screws on the frame are adjusted to maintain tension between the sections which allows the bone to grow back together slowly into a complete but longer bone.
Hormone Therapy: To promote growth in children diagnosed with dwarfism, injections of a synthetic version of the growth hormone may be among their treatment. Children can receive daily injections for several years until they reach a maximum adult height. In some cases, these injections can last into early adulthood to guarantee adult maturation including the appropriate gain in fat or muscle.