Dwarfism

Dwarfism is when a person is short in stature because of their genes or a medical reason. It’s defined by the advocacy groups Little People of the World Organization (LPOTW) and Little People of America (LPA) as an adult height of 4 feet 10 inches or under, as a result of a medical or genetic condition. Other groups extend the criteria for certain forms of dwarfism to 5 feet, but the average height of an adult with dwarfism is 4 feet.

There are two main categories of dwarfism -- disproportionate and proportionate.

Disproportionate dwarfism is characterized by an average-size torso and shorter arms and legs or a shortened trunk with longer limbs.

In proportionate dwarfism, the body parts are in proportion but shortened.

In addition to short stature, dwarfism has many other symptoms that can vary depending the type it is.

Disproportionate dwarfism symptoms

Disproportionate dwarfism usually doesn’t affect intellectual development unless a child has other rare conditions, including hydrocephalus, or excess fluid around the brain.

Symptoms of disproportionate dwarfism may include:

Adults typically are about 4 feet tall

Average-size torso and very short limbs, especially in the upper halves of arms and legs

Short fingers

Wide spaces between the middle and ring fingers

Limited elbow mobility

Disproportionately large head

Prominent forehead

Flattened bridge of the nose

Bowing of legs that progressively worsens over time

Swaying of the back that progressively worsens over time

Some people with disproportionate dwarfism have a rare disorder called spondyloepiphyseal dysplasia congenita (SEDC). Adults with SEDC are around 3 to 4 feet tall and may have these signs too:

Very short trunk

Short neck, arms, and legs, but average-size hands and feet

Broad chest

Flattened cheekbones

Cleft palate, or an opening in the roof of the mouth

Unstable neck bones

Deformed hips where the thigh bones turn inward

Twisted feet

Hunched upper back that progressively worsens

Swayed lower back that progressively worsens

Arthritis

Joint mobility problems

Impaired vision or hearing

Proportionate dwarfism symptoms

Proportionate dwarfism is caused by a medical condition you have at birth or that develops in childhood that hinders growth and development. One common cause is too-low amounts of growth hormone produced by your pituitary gland.

Symptoms of proportionate dwarfism include a smaller head, arms, and legs. But all are in proportion with each other. Organ systems may be smaller too.

Other signs of proportionate dwarfism in children are:

Slower growth rate than expected for their age

Height lower than the third percentile on standard charts for age

Delayed or no sexual development during the teen years

There are approximately 400 types of dwarfism. Causes of proportionate dwarfism include metabolic and hormonal disorders such as growth hormone deficiency.

The most common types of dwarfism, known as skeletal dysplasias, are genetic. Skeletal dysplasias are conditions of abnormal bone growth that cause disproportionate dwarfism.

They include:

Achondroplasia. The most common form of dwarfism -- accounting for 70% of cases -- achondroplasia occurs in about one out of 26,000 to 40,000 babies and is evident at birth. People with achondroplasia have a relatively long trunk and shortened upper parts of their arms and legs. Other features of achondroplasia include:

A large head with a prominent forehead

A flattened bridge of the nose

Protruding jaw

Crowded and misaligned teeth

Forward curvature of the lower spine

Bowed legs

Flat, short, broad feet

"Double-jointedness"

Spondyloepiphyseal dysplasias (SED).A less common form of dwarfism, SED affects approximately one in 95,000 babies. Spondyloepiphyseal dysplasia refers to a group of conditions characterized by a shortened trunk, which may not become apparent until a child is between ages 5 and 10. Other features can include:

Club feet

Cleft palate

Severe osteoarthritis in the hips

Weak hands and feet

Barrel-chested appearance

Risk factors for dwarfism include a hormone deficiency or malnutrition. There usually aren't any risk factors for a hormone deficiency, but it can often be successfully treated. Serious malnutrition, which leads to weak bones and muscles, can also be overcome in many cases with a healthy, more nutrient-rich diet.

Disproportionate dwarfism causes changes to the limbs, back, and head size that could cause complications like these:

Arthritis

Back pain or breathing difficulties due to hunched or swayed back

Bowed legs

Crowded teeth

Delayed motor skills development

Frequent ear infections and possibly hearing loss

Hydrocephalus (fluid on the brain)

Pressure on the spine at the base of the skull

Sleep apnea

Spinal stenosis, a narrowing of the spine that may cause leg pain or numbness

Weight gain that may cause back problems

risk factors for dwarfism include a hormone deficiency or malnutrition. There usually aren't any risk factors for a hormone deficiency, but it can often be successfully treated. Serious malnutrition, which leads to weak bones and muscles, can also be overcome in many cases with a healthy, more nutrient-rich diet.