Any change or mutation in the DNA sequence of a human gives rise to a genetic disorder. Classified into different types, the primary cause of a genetic disease is basically an abnormality that can range from minuscule to major. Some disorder of this kind is derived from parents while others can be caused by mutations in pre-existing genes or congenital.
People who inherit the genetic defect may be immune to cancer and other diseases. By Gary Taubes Wednesday, March 27, This Ecuadorian man with Laron syndrome shown with his children in the early s lived free of cancer and diabetes to age 87, a decade longer than the average Ecuadorian.
He was killed in a car accident in For the past decade, the endocrinologist had treated several Ecuadorian children with growth hormone deficiency, a common type of dwarfism, at his clinic at the University of Florida. Now, for the first Genetic disorder essay, he had flown down to South America to treat them at home.
The plan was to give six patients their biannual dose of growth hormone, saving them the expense of visiting Rosenbloom in the States. Out of the stream of patients, the ones that struck him most were two sisters, ages 6 and 8. The girls were both less than three feet tall, about the height of a typical 1-year-old.
They had prominent foreheads, piping voices, and depressed nasal bridges.
Only a hundred or so cases of Laron syndrome had ever been diagnosed. Once Rosenbloom returned to Florida, he wondered if and when treatment would be available to the sisters, but the syndrome itself faded from his attention.
Diagnosing the occasional rare genetic disorder is part and parcel of the practice of pediatric endocrinology, and he had no reason to give the syndrome much more thought. But by the time he returned to Ecuador to treat his growth-hormone-deficient patients six months later, one of the local endocrinologists, Jaime Guevara-Aguirre, had diagnosed another seven cases, all from the province of Loja in the south.
To the two doctors conferring on the finds, the implication was obvious: If there were nine cases in one region, there were assuredly more. A natural assumption among physicians is that someone of severely short stature likely suffers from a deficiency in growth hormone, the molecule secreted by the pituitary gland that is responsible for the surge in height experienced by most children and adolescents.
But in the late s, Israeli endocrinologist Zvi Laron discovered an important exception to that rule. Physicians throughout Israel began sending him patients, some with childhood diabetes and others with growth and sexual development disorders.
They all had the same general appearance: They came from a Jewish family, recently arrived in Israel from Yemen. Their grandparents were first cousins, a close connection that implied the children inherited copies of a single defective gene.
Laron assumed the simplest explanation: The siblings had a severe shortage of growth hormone. Inhe finally got the chance to evaluate his hypothesis with a newly developed hormonal blood test. As it turned out, the levels of growth hormone were abnormal—they were extremely high.
Either these people had defective hormones, Laron reasoned, or something was wrong with the cells that respond to those hormones. Jaime Guevara-Aguirre above, with some participants in his research was the first to identify a population of Ecuadorians with Laron syndrome.
Every cell in the body contains receptors—essentially tiny locks—on its surface. A hormone is like a microscopic key floating in the bloodstream: When it finds a matching lock, it binds to the receptor and triggers the cell to do something, such as grow or divide.
But while analyzing the liver cells of two of his patients, Laron found that normal growth hormone failed to bind to its associated receptor, suggesting that the receptors were damaged. Inhe published a paper showing that the short stature of people with Laron syndrome results from their inability to respond to growth hormone, no matter how much they have floating around.
One piece of the puzzle came from research by endocrinologist William Daughaday of Washington University in St. In Daughaday discovered the hormone now called insulin-like growth factor 1, or IGF When growth hormone binds to a receptor, he found, it sets off a chain reaction that leads to the production of IGF It is IGF-1, not growth hormone, that stimulates the cell to grow and divide to form new cells.We also know a great deal, although not nearly enough, about the underlying biology of suicide.
For example, there is a genetic component that is probably independent of, but interacts dangerously with, the genetic factors implicated in the major psychiatric illnesses (see David Brent’s article).We know that neurotransmitters such as serotonin, norepinephrine, and dopamine are deeply.
One of the most destructive myths of modern times is that people of all races have the same average intelligence. It is widely accepted that genes account for much of the difference in intelligence between individuals, but many people still refuse to believe genes explain group differences in .
See the winners and read their essays on the DNA Day Essay Contest Winners' Page!Congratulations to the winners and honorable mentions. A diagnosis of borderline personality disorder could, theoretically, mean that the psychiatrist made a serious attempt at evaluating defense mechanisms and ego integrity; or at least a matching of symptoms to DSM criteria.
It's theoretically possible, yes. The DIY Scientist, the Olympian, and the Mutated Gene How a woman whose muscles disappeared discovered she shared a disease with a muscle-bound Olympic medalist. Hemochromatosis is an iron overload disorder in which a person absorbs too much iron from the food and drink they consume.
Left untreated, it can damage various organs in the body.