Dwarfism: Definition, Symptoms, Types, Causes, Diagnosis and Treatment

It occurs when a person is unusually short. Dwarfism itself is not a disease, and as a result, it does not have a single medical definition.

Different organizations define dwarfism according to various criteria. The advocacy group, Little People of America, defines dwarfism as a condition that results in an adult height of less than 4 feet 10 inches.

Medically, a person is considered to have dwarfism when they have a condition that makes them very short. Mutations that stunt growth and produce individuals with markedly reduced height, or dwarfism, are known in many species.

One of the seven genetic traits originally analyzed by Mendel in his formulation of the laws of heredity was dwarfism in the garden pea.

Recently, Mendel’s dwarf mutation has been shown to affect the production of the hormone gibberellin, which is essential for the elongation of the internodes. In humans, mutations in at least 320 genes can cause short stature often along with other abnormalities.

But society might regard a person as a dwarf based solely on short stature. Dwarfism is not a disorder, but diseases sometimes arise with it. Some examinees with dwarfism may have chronic joint pain due to abnormal bone growth or alignment.

This is especially the case when it involves the spine. Dwarfism has many different causes. Several of the causes of dwarfism can lead to other health problems, such as osteoarthritis.

Fast facts on dwarfism:

  • Dwarfism makes a person very short in stature.
  • Dozens of medical conditions can cause dwarfism.
  • The diagnosis is often only made after the birth of a child.
  • Most people with dwarfism can do everything that people can do on average.

Symptoms of dwarfism and restricted growth

Restricted growth, sometimes known as dwarfism, is a condition characterized by unusually short height. There are 2 main types of restricted growth:

Proportionate short stature – a general lack of growth in the body, arms, and legs.

Disproportionate short stature : where the arms and legs are particularly short.

Some people with restricted growth also have other physical problems, such as bowed legs or an unusually curvy spine.

But most people do not have any other serious problems and can live a relatively normal life, with a normal life expectancy.

Types

This condition is the result of a variety of disorders that affect the growth and development of tissues.

Some conditions that cause dwarfism disrupt the hormones that allow the body to grow. Dwarfism can also be due to metabolic disorders or malnutrition. A group of conditions called skeletal dysplasias is the most common cause of dwarfism.

Skeletal dysplasias cause bones to grow abnormally, resulting in small stature. This abnormal growth can also lead to uneven growth that produces a body of unusual proportions.

Skeletal dysplasias are classified according to whether they predominantly affect the proximal or distal long bones of the limb. Rhizomelic dysplasias (rizo- meaning “root” and “melica” meaning “limb”) affect the femur and humerus more than the tibia or radius.

Mesomelic dysplasia (meso, meaning “middle”) describes the shortening of the distal long bones (tibia, ulna, and radius) or half of the limb relative to the proximal limb (humerus or femur).

Acromelic dysplasia (acro, meaning “extreme”) is a growth disturbance that affects the distal portions of the extremities (hands and feet).

Micromeline dysplasia involves both the proximal and distal parts of the limb. Short spinal dysplasias cause dwarfism without involving the extremities.

Skeletal dysplasias are typically genetic conditions. Most people with skeletal dysplasias have parents of normal height.

The three most common types of skeletal dysplasia are achondroplasia, congenital spondyloepiphyseal dysplasia, and diastrophic dysplasia.

Acondroplasia

Human achondroplasia mutations are dominant mutations of the fibroblast growth factor receptor 3 (FGFR3) gene. Many of these human mutations appear to be spontaneously generated in a parental germ cell.

In early childhood, much of the cartilage a person is born with turns into harder bone. In achondroplasia, this process does not occur as effectively.

Achondroplasia mainly affects the bones of the arms and legs. Achondroplasia is a genetic disorder present at birth. Its symptoms include:

  • A normal size torso.
  • Very short arms and legs, which can be difficult to move.
  • A great forehead.

Some people with achondroplasia develop bone problems, such as scoliosis, have trouble breathing, or have a narrowing of the spine called spinal stenosis.

A rare form of achondroplasia occurs when people inherit two copies of a mutated gene that causes achondroplasia. This leads to very short bones and an underdeveloped rib cage.

Most people with this disorder are stillborn or die in infancy because they cannot breathe. In dogs, this defect is responsible for the distinctive body shape of the dachshund and basset hound.

Congenital spondyloepiphyseal dysplasia

Spondyloepiphyseal dysplasia congenital (SEDC) is a genetic mutation that causes a short torso, short arms, and short legs.

The spine, arms, and legs of people with this condition do not grow as expected. This makes them very short, but produces typical sized hands, feet and head.

In addition to short stature, people with congenital spondyloepiphyseal dysplasia can experience a variety of health problems, including:

  • Spine and hip problems.
  • Foot deformities.
  • Cleft palate
  • Joint diseases.

Congenital spondyloepiphyseal dysplasia can change the shape of the face, making the facial bones appear flat.

Diastrophic dysplasia

Diastrophic dysplasia is the result of a genetic mutation. It affects the development of cartilage and bone, causing very short arms and legs and a short stature.

People with this condition commonly have spinal deformities and a condition called hitchhiker’s thumb that changes the shape of the thumbs.

People with diastrophic dysplasia often develop joint pain and mobility problems in childhood. They may have scoliosis, clubfoot, or trouble moving.

Dystrophic dysplasia can cause breathing problems, particularly in childhood. Some children with this condition die of respiratory problems.

What Causes Restricted Growth?

Causes of proportionate short stature

The most common cause of proportional short stature is being born to young parents, but it is sometimes the result of the body not producing enough growth hormone.

Certain genetic syndromes, such as Turner syndrome, Noonan syndrome, and Prader-Willi syndrome, can also cause proportional short stature.

Causes of disproportionate short stature

The genetic condition mentioned above called achondroplasia is the most common cause of disproportionate short stature. It doesn’t always run in the family – many children with achondroplasia have parents of normal height.

Other types of dwarfism

Other causes of dwarfism can be due to:

  • Organ failure that undermines the body’s ability to make hormones or metabolize nutrients.
  • Insufficient levels of certain hormones, particularly human growth hormone (HGH).
  • Malnutrition or lack of enough food, causing growth problems.

All of these are secondary causes of dwarfism. This means that they are not genetic and can be reversible with early detection and prompt treatment.

How is dwarfism diagnosed?

The most common forms of dwarfism, which are caused by genetic abnormalities of the skeleton and cartilage, can be detected by genetic testing while the fetus is still developing.

Most doctors only perform these tests when there is reason to believe that a fetus is at risk when dwarfism runs in a family.

Because most people with dwarfism have parents of normal height, the condition is usually not detected until after birth.

Skeletal dysplasias, the most common type of dwarfism, can usually be diagnosed shortly after birth. X-rays, genetic testing, and a physical exam are often enough to diagnose the condition.

Less common forms of dwarfism usually appear later in life. They can be more difficult to diagnose, particularly if a child has no symptoms other than short stature.

Growth hormone deficiency is usually diagnosed with growth hormone stimulation tests.

The medicine is injected into a vein or muscle to cause an increase in growth hormone levels in the blood. A level below normal indicates a deficiency in growth hormone.

A brain scan will be needed to look at the pituitary gland (which makes growth hormone) if blood tests show low levels of growth hormone.

Blood tests to measure human growth hormone levels, tests to assess the health of the organ, and a complete medical history usually reveal the cause.

If one or both parents have a family history of a condition that causes short stature, their baby can be tested during pregnancy (prenatal diagnosis).

Treatment and management

Some metabolic and hormonal causes of dwarfism can be reversible.

Injections with human growth hormone, for example, can help people with growth hormone deficiency to grow to a normal height and can help a child with this condition grow larger than they would.

The most common causes of dwarfism, however, are not curable. Instead, treatments focus on managing symptoms, including:

Surgery to correct abnormalities in the bones and spinal cord. In cases of disproportionate short stature where the legs are particularly short, a leg lengthening procedure is sometimes used, but there is some uncertainty about its safety and effectiveness.

Removal of the tonsils or adenoids to make it easier to breathe. Spinal decompression surgery. Using a tube called a shunt to drain fluid from the brain.

Lifestyle changes, such as exercise and weight loss. People with many forms of dwarfism are vulnerable to obesity. The extra weight can increase your risk of heart problems.

Living with dwarfism

People with dwarfism may need help with related medical conditions, such as osteoarthritis . However, very short people can and do lead normal lives.

Many people with dwarfism say that the hardest part of their condition is the stigma attached to it. This stigma can include harassment and discrimination in employment, as well as the use of negative terms such as “dwarf.”

Because people with dwarfism have special medical needs, most need regular visits with a team of doctors, including bone and cartilage specialists. However, with symptom management, it is possible for a person with dwarfism to live a long and healthy life.

Dwarfism does not have to be viewed as a disabling condition. The TLC show, Little People, Big World, shares the stories of people with dwarfism who lead typical lives. Treating dwarfism as a disability can make very short people feel stigmatized.