Gigantism
Genetic Disorders are diseases caused by an abnormality in an individual's DNA. The abnormalities can range from a small mutation in a single gene to the addition or subtraction of an entire chromosome or set of chromosomes. Many diseases have a genetic aspect. Some mutations can occur randomly or because of an environmental exposure such as cigarette smoke. Other genetic disorders are inherited. A mutated gene is passed down through family and each generation can inherit the gene that causes the disease. Still other genetic disorders are due to problems with the number of packages of genes called chromosomes. For example, in Down syndrome, there is an extra copy of chromosome 21.
There are 4 types of genetic disorders. They are: single-gene, multifactorial, chromosomal and mitochondrial. The single-gene type is caused by changes or mutations that occur in the DNA sequence of one gene. The multifactorial type is caused by a combination of environmental factors and mutations in multiple genes. The chromosomal type is due to chromosomes being carriers of genetic material. Such abnormalities in chromosome structure as missing or extra or extra copies can result in disease. The mitochondrial type is rare and it is caused by mutations in the non-chromosomal DNA of the mitochondria.
Gigantism, also know as giantism, is abnormally large growth due to an excess of growth hormone during childhood, before the bone growth plates have closed. In some cases, the condition may be passed on genetically through a mutated gene. Growth hormones stimulate growth, cell reproduction, and regeneration. The most common cause of too much growth hormone release is a non-cancerous tumor of the pituitary gland. Other causes might include Carney complex, McCune-Albright syndrome, Multiple endocrine neoplasia type 1, and Neurofibromatosis. Carney complex is a disorder characterized by an increased risk of several types of tumors. McCune-Albright syndrome is a genetic disease that affects the bones and color of the skin. Multiple endocrine neoplasia type 1 is an inherited disorder in which one or more of the endocrine glands are overactive or form a tumor. Endocrine glands most commonly involved are the pancreas, the parathyroid, and the pituitary. Neurofibromatosis can cause growth of non-cancerous tumors on nerve tissue, producing skin and bone abnormalities.
Gigantism is very rare. If a child has Gigantism, the child will grow in height, as well as in the muscles and organs. The excessive growth makes the childabnormally large for their age. Symptoms include delayed puberty, double vision or difficulty with side vision, unusually prominent forehead and a prominentjaw, headaches, increased sweating, irregular periods, large hands and feet with thick fingers and toes, release of breast milk, thickening of the facial features and weakness.
Treatments for Gigantism include surgery and medication. If surgery and medication fail, they will use radiation therapy. In surgery, they try to completely remove the tumor. The surgery can cure many cases. For situations where they cannot completely remove the tumor, medication is the treatment of choice. The most effective medications are somatostatin analogs. This medication reduces growth hormone release. Dopamine agonists have also been used to reduce growth hormone release, but this medication is usually less effective. Pegvisomant is a medication that may also be used. It blocks the effect of growth hormone. Radiation therapy may be used if all else fails. It brings the growth hormone levels back to normal. However, it may take 5-10 years for full effects to be seen and almost always leads to low levels of other pituitary hormones. Side effects of radiation therapy include learning disabilities, obesity and emotional changes in children. Pituitary surgery can also be successful in limiting growth hormone production. Low levels of other pituitary hormones include adrenal insufficiency, diabetes insipidus, hypogonadism (sex glands produce little or no hormones), and hypothyroidism (thyroid glands do not make enough thyroid hormone).
Another complication may include delayed puberty.
Human gene therapy is insertion of normal DNA directly into cells to correct a genetic defect. It is the treatment of disease by replacing, altering or supplementing a gene that is absent or abnormal and whose absence or abnormality is responsible for a disease.
Dalip Singh, a professional wrestler and actor (Get Smart) who has Gigantism. He is 7 foot 1 inch and weighs 347 pounds. He had surgery to remove his tumor.
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