Adult individuals, below 4 feet and 10 inches of height are considered as dwarf. Dwarfism is majorily caused by a random genetic mutation in a sperm or an egg, during fertilization process. It may also be a result of genetic disorder but exact cause of such disorder is still not clear.
Around 70 to 80% of dwarfism happens due to the medical condition known as achondroplasia. There are around 500 diseases that are known to be related with dwarfism, but these can be easily categorized into three major physiological causes of dwarfism.
Different Causes Of Dwarfism With Most Prevalent Forms
Constitutional Bone Dwarfism
Growth and developmental abnormalities of cartilage and bones occurs in constitutional bone dwarfism that affects skeletal morphology and overall structure.
The most commonly occurring and known cause of dwarfism is achondroplasia. This is a kind of disproportionate dwarfism, where the epiphysial cartilage is not formed properly, and development of long bones of legs and arm happens slowly, with difficulty. Growth ends at a comparatively early stage than those who do not show this disorder.
The average height in adult male remains 125 cm and an adult female shows an average height of 120 cm. This kind of dwarfism is usually detected at birth only, with specific features like round face with disproportionate head in contrast to rest of the parts of the body, a low nasal bridge and a protruding prominent forehead.
A form of dwarfism with shorter limbs and trunks but remain in proportion is called as Spondyleopiphyseal Dysplasia. The skull and face remains unaffected with normal sized feet and hands. The neck is shorter than usual giving a stocky look, with a prominent sternum. The prognostic varies and depends on how severely the disease affects the hips and can be very harmful.
Metabolic Bone Dwarfism
A set of chemical reactions of metabolism may become faulty and then metabolism of carbohydrates, fats, phosphorus and calcium gets affected in certain diseases, leading to metabolic bone dwarfism.
Pituitary gland is present at the base of the brain, which produces various important hormones like growth hormones. In pituitary dwarfism, growth rate of pituitary hormones decreases substantially resulting in fewer productions of hormones, known as hypopituitarism. Since, growth hormone production decreases, bones growth get affected severely, resulting in dwarfism.
This form of dwarfism can be efficiently treated with growth hormone injections. Hence, detection of pituitary dwarfism at an early stage can reverse the cause of dwarfism.
The second most commonly occurring form of dwarfism is Morquio syndrome. This a severe type of dwarfism, where growth gets stopped at 8 or 10 years of age, with an increase of 1 m height thereafter and rarely exceed beyond a height of 125 cm. These individuals have difficulties in walking (waddling gait) and possess deformed sternum and thoracic cavity.
The thoracic cavity protrudes out prominently in front of the torso and legs, and arms are deformed even after attaining normal size. People with morquio syndrome have wide and short trunk, short neck giving a stocky look and joints are generally weak, majorily the hip joints.
Secondary Bone Dwarfism
Certain disorders of bone lead to this form of dwarfism, where the symptoms remain secondary. Primordial Dwarfism (Intrauterine Growth retardation) Children born full term but smaller at birth due to intrauterine growth retardation show primordial dwarfism. Most children will not be able to make up the loss of height but the growth will be well proportioned. The causes could be many for intrauterine growth retardation but not fully understood so far.
Turner syndrome is only observed in females as it results from having one X chromosome (X0) instead of usual two X (2X) chromosomes that are normally present in females. The average height reaches up to 140 cm, in absence of any growth hormone treatment and females remain infertile.
Seckel syndrome form of dwarfism is very rare and is characterized by a small shape face with low forehead that recedes. The lower jawbone is pushed apart from the upper jawbone.
Node is more curved like beak of a bird, and is also popularly called as bird head dwarfism. The limbs and trunk remains short with a proportionate dwarfism. The height of an adult is not more than 128 cm.
Dwarfism is not a disease, but a disorder that can give rise to more complications. A few forms of dwarfism can be easily managed and may be reverted, as in case of hypopituitarism (pituitary dwarfism). Nevertheless, dwarfism is not a hindering factor for dwarfs as they may lead a healthy and happy life, like other normal individuals.
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