Dwarfism

Dwarfism - What is Dwarfism?

Dwarfism is short stature resulting from a particular medical condition. It is sometimes defined as an adult height of less than 4 feet 10 inches (147 cm), although this definition is problematic because short stature in itself is not a disorder.

Dwarfism can be caused by about 200 distinct medical conditions.

''Disproportionate'' dwarfism is characterized by one or more body parts' being relatively large or small in comparison to those of a normal adult, with growth abnormalities in specific areas being apparent. 

In cases of ''proportionate'' dwarfism, the body appears normally proportioned, but is abnormally small. 

Historically, the term midget was used to describe "proportionate dwarfs"; however, this term has now become offensive and pejorative. 

Hypotonia, or a lack of muscle, is common in dwarfs, but intelligence and lifespan are usually normal.

Achondroplasia is a bone-growth disorder responsible for 70% of dwarfism cases.

There is no single treatment for dwarfism. Individual abnormalities, such as bone-growth disorders, sometimes can be treated through surgery, and some hormone disorders can be treated through medication, but usually it is impossible to treat all the symptoms of dwarfism. 

Lifestyle changes often are needed to cope with the effects of dwarfism. Such devices as specialized furniture often help people with dwarfism to function normally. 

Many support groups help individuals with dwarfism cope with the challenges they face and with developing and maintaining their independence.

Dwarfism is a highly visible condition and often carries negative connotations in society. Because of their unusual height, people with dwarfism are often used as spectacles in entertainment and portrayed with stereotypes. 

For a person with dwarfism, heightism can lead to ridicule in childhood and discrimination in adulthood.

Short stature can be inherited without any coexisting disease. Short stature in the absence of any abnormal medical condition is not generally considered dwarfism. For example, a short man and a short woman who are in normal health will tend to produce children who are also short and in normal health. 

While short parents tend to produce short children, persons with dwarfism may produce children of normal height, if the cause of their dwarfism is not genetically transmissible or if the individual does not pass on the genetic mutation.

Many types of dwarfism are impossible to prevent because they are genetically caused. Genetic conditions that cause dwarfism may be identified with genetic testing, by screening for the specific abnormalities that result in the condition. However, due to the number of causes of dwarfism, it may be impossible to determine definitively if a child will be born with dwarfism.

Dwarfism resulting from malnutrition or a hormonal abnormality may be treated with an appropriate diet or hormonal therapy. Growth hormone deficiency may be remedied via injections of Human Growth Hormone (HGH) during early life.

Genetic defects of most forms of dwarfism caused by bone dysplasia cannot be corrected, so therapeutic interventions are typically aimed at preventing or reducing pain or physical disability, increasing adult height, or mitigating psychosocial stresses and enhancing social adaptation.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Dwarfism" All material adapted used from Wikipedia is available under the terms of the GNU Free Documentation License. Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.

Dwarfism Classification

Dwarfism is a medical disorder with the sole requirement being an adult height under and it is almost always classified as to the underlying condition that is the cause for the short stature. 

Dwarfism is not necessarily caused by disease or a genetic disorder; it can simply be a naturally occurring consequence of a person's genetics. If dwarfism is caused by a medical disorder, the person is referred to by the underlying diagnosed disorder. 

Disorders causing dwarfism are often classified by proportionality. Disproportionate dwarfism describes disorders that cause abnormal proportions of the body parts, while proportionate dwarfism results in a generally uniform stunting of the body.

Disorders that cause dwarfism may be classified according to one of hundreds of names, which are usually permutations of the following roots:

  • location
    • rhizomelic = root, e.g., bones of the upper arm or thigh
    • mesomelic = middle, e.g., bones of the forearm or lower leg
    • acromelic = end, e.g., bones of hands and feet.
    • micromelic = entire limbs are shortened
    • source
      • chondro = of cartilage
      • osteo = of bone
      • spondylo = of the vertebrae
      • plasia = form
      • trophy = growth

Examples include achondroplasia, osseous dysplasia, chondrodystrophy, and osteochondrodystrophy.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Dwarfism" All material adapted used from Wikipedia is available under the terms of the GNU Free Documentation License. Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.

Dwarfism Characteristics

A typical defining characteristic of dwarfism is an adult height of less than. Since those with dwarfism have such a wide range of physical characteristics, oddities in individuals are identified by diagnosing and monitoring the underlying disorders.

Disproportionate dwarfism is characterized by one or more body parts being disproportionately large or small compared to the rest of the body. In achondroplasia the trunk is normally sized with the limbs being disproportionately short, the head being larger than usual, and the forehead being prominent. 

Height is significantly below average and there may be long periods without any significant growth. 

Sexual development is often delayed or impaired into adulthood. Unlike disproportionate dwarfism, mental capacity may be diminished in some cases of proportionate dwarfism. The overall stunted growth can lead to impaired intelligence when compared to the physical age.

Physical maleffects of malformed bones vary according to the specific disease. Many involve joint pain caused by abnormal bone alignment, or from nerve compression. Reduced thoracic size can restrict lung growth and reduce pulmonary function. 

Some forms of dwarfism are associated with disordered function of other organs, such as the brain or liver, sometimes severely enough to be more disabling than the abnormal bone growth.

Mental effects also vary according to the specific underlying syndrome. In most cases of skeletal dysplasia, such as achondroplasia, mental function is not impaired in any way.

The psychosocial disadvantages may be more distressing than the physical symptoms, especially in childhood and adolescence, but people with dwarfism vary greatly in the degree to which social participation and emotional health are affected.

  • Social prejudice against extreme shortness may reduce social and marital opportunities.
  • Numerous studies have demonstrated reduced employment opportunities. Severe shortness is associated with lower income.

Achondroplasia

The most recognizable and most common form of dwarfism is achondroplasia, which accounts for 70% of dwarfism cases and produces rhizomelic short limbs, increased spinal curvature, and distortion of skull growth. 

Achondroplasia is an autosomal dominant disorder caused by the presence of a faulty allele in a person's genome. 

If a pair of achondroplasia alleles are present, the result is fatal. Achondroplasia is a mutation in the fibroblast growth factor receptor gene 3 (), which is an inhibitor that regulates bone growth. In cases of achondroplasia, the FGFR3 gene is too aggressive, negatively impacting bone growth.

Research by urologist Harry Fisch of the Male Reproductive Center at Columbia Presbyterian Hospital indicates that this defect may be exclusively inherited from the father and becomes increasingly probable with paternal age; specifically males reproducing after 35.

Growth hormone deficiency

Growth hormone deficiency (GHD) is a medical condition in which the body produces insufficient growth hormone. 

Growth hormone, also called somatotropin, is a polypeptide hormone which stimulates growth and cell reproduction. 

If this hormone is lacking, stunted or even halted growth may become apparent. Children with this disorder may grow slowly and puberty may be delayed by several years, or even indefinitely. 

Growth hormone deficiency has no single definite cause. It can be caused by mutations of specific genes, damage to the pituitary gland, Turner's syndrome, poor nutrition, or even stress (leading to psychogenic dwarfism).

Other

Other causes of dwarfism include spondyloepiphyseal dysplasia congenita, diastrophic dysplasia, pseudoachondroplasia, hypochondroplasia, Noonan syndrome, primordial dwarfism, Turner syndrome, osteogenesis imperfecta (OI) and hypothyroidism. Severe shortness with skeletal distortion also occurs in several of the Mucopolysaccharidoses and other storage disorders.

Serious chronic illnesses may produce dwarfism as a side effect. Harsh environmental conditions, such as malnutrition, may also produce dwarfism. 

These types of dwarfism are indirect consequences of the generally unhealthy or malnourished condition of the individual, and not by any specific disease. 

The dwarfism often takes the form of simple short stature, without any deformities. 

In societies where poor nutrition is widespread, the average height of the population may be reduced below its genetic potential by the lack of proper nutrition.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Dwarfism" All material adapted used from Wikipedia is available under the terms of the GNU Free Documentation License. Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.

Dwarfism Diagnosis

Dwarfism is often diagnosed in childhood on the basis of visible symptoms. A physical examination can usually suffice to diagnose certain types of dwarfism, but genetic testing and diagnostic imaging may be used to determine the exact condition. 

In a person's youth, growth charts that track height can be used to diagnose subtle forms of dwarfism that have no other striking physical characteristics.

During an initial medical evaluation of shortness, the absence of disproportion and other clues listed above usually indicates causes other than bone dysplasias. Extreme shortness with completely normal proportions sometimes indicates growth hormone deficiency (pituitary dwarfism).

Short stature alone, in the absence of any other abnormalities, may be the result of the distribution of offspring height from short-statured parents, rather than a symptom of any medical condition.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Dwarfism" All material adapted used from Wikipedia is available under the terms of the GNU Free Documentation License. Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.