Biology CHEMICAL CO-ORDINATION AND INTEGRATION

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CHEMICAL CO-ORDINATION AND INTEGRATION

Dwarfism

Dwarfism is short stature that results from a genetic or medical condition. Dwarfism is generally defined as an adult height of 4 feet 10 inches (147 centimeters) or less. The average adult height among people with dwarfism is 4 feet (122 cm).

# Many different medical conditions cause dwarfism. In general, the disorders are divided into two broad categories:
- Disproportionate dwarfism. If body size is disproportionate, some parts of the body are small, and others are of average size or above-average size. Disorders causing disproportionate dwarfism inhibit the development of bones.

- Proportionate dwarfism. A body is proportionately small if all parts of the body are small to the same degree and appear to be proportioned like a body of average stature. Medical conditions present at birth or appearing in early childhood limit overall growth and development.

Dwarfism is short stature that results from a genetic or medical condition. Dwarfism is generally defined as an adult height of 4 feet 10 inches (147 centimeters) or less. The average adult height among people with dwarfism is 4 feet (122 cm).

# Many different medical conditions cause dwarfism. In general, the disorders are divided into two broad categories:
- Disproportionate dwarfism. If body size is disproportionate, some parts of the body are small, and others are of average size or above-average size. Disorders causing disproportionate dwarfism inhibit the development of bones.

- Proportionate dwarfism. A body is proportionately small if all parts of the body are small to the same degree and appear to be proportioned like a body of average stature. Medical conditions present at birth or appearing in early childhood limit overall growth and development.

Causes of Restricted Growth

Causes of restricted growth
- Restricted growth (dwarfism) may be caused by many different medical conditions, and is more noticeable in some conditions than others. Causes of proportionate short stature :
# The main cause of proportionate short stature (PSS) is being born to small parents.
# A less common cause is the body not producing enough growth hormone, which is estimated to affect one in every 3,500 to 4,000 children.
#This may be present at birth, because of problems with the pituitary gland (a pea-sized gland below the brain responsible for producing several important hormones) or as part of another condition. It can also start in childhood, as the result of an injury, a brain tumour or radiotherapy to the brain.
# In about half of children with growth hormone deficiency, the cause is unknown.

- Other possible causes of PSS include:
# long-term conditions – such as those affecting the lungs, heart or kidneys
# steroid treatment for a chronic condition – such as asthma
# genetic abnormalities – such as Down's syndrome, Noonan syndrome, Turner syndrome, Prader-Willi syndrome and short stature homeobox-containing gene (SHOX) deficiency
# malnutrition or poor absorption of food – for example, in coeliac disease

# Growth hormone deficiency : The cause of growth hormone deficiency can sometimes be traced to a genetic mutation or injury, but for most people with the disorder, no cause can be identified.

Causes of restricted growth
- Restricted growth (dwarfism) may be caused by many different medical conditions, and is more noticeable in some conditions than others. Causes of proportionate short stature :
# The main cause of proportionate short stature (PSS) is being born to small parents.
# A less common cause is the body not producing enough growth hormone, which is estimated to affect one in every 3,500 to 4,000 children.
#This may be present at birth, because of problems with the pituitary gland (a pea-sized gland below the brain responsible for producing several important hormones) or as part of another condition. It can also start in childhood, as the result of an injury, a brain tumour or radiotherapy to the brain.
# In about half of children with growth hormone deficiency, the cause is unknown.

- Other possible causes of PSS include:
# long-term conditions – such as those affecting the lungs, heart or kidneys
# steroid treatment for a chronic condition – such as asthma
# genetic abnormalities – such as Down's syndrome, Noonan syndrome, Turner syndrome, Prader-Willi syndrome and short stature homeobox-containing gene (SHOX) deficiency
# malnutrition or poor absorption of food – for example, in coeliac disease

# Growth hormone deficiency : The cause of growth hormone deficiency can sometimes be traced to a genetic mutation or injury, but for most people with the disorder, no cause can be identified.

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