Genetic and Birth Defects Due to Radiation Exposure Term Paper

  • Length: 6 pages
  • Subject: Genetics
  • Type: Term Paper
  • Paper: #44332714

Excerpt from Term Paper :

bombing of Hiroshima studies have been conducted analyzing the impact that radiation exposure has on unborn children.

One study that was conducted on children who were conceived and born in Hiroshima and Nagasaki after they were bombed concluded that radiation can affect the incidence of genetic birth defects.

Birth defects caused by exposure to radiation have been linked to genetics.

A defect occurs when there are changes in the DNA.

Additional research has shown that infant death rates dropped dramatically when reactors were closed down from when they were in operation.

The research is in and there is no denying the impact radiation has on genetic birth defects.

CONCLUSION

This paper presents a detailed examination of genetic birth defects that are caused by exposure to radiation. The writer explores the problem with radiation exposure and the development of fetal birth defects because of it. There were seven sources used to complete this paper.

Introduction

Since shortly after the bombing of Hiroshima studies have been conducted analyzing the impact that radiation exposure has on unborn children. For several decades the medical community has alerted the public to the incidence of birth defects that are directly related to radiation. Genetic birth defects underscored the long-term impact that exposure to radiation has on the body and on future offspring.

Background

The dropping of the bomb in Japan started the trail leading to the world's current knowledge when it comes to birth defects caused by radiation.

One study that was conducted on children who were conceived and born in Hiroshima and Nagasaki after they were bombed concluded that radiation can affect the incidence of genetic birth defects.

The survey began in the late spring of 1948 and continued over the following six years. During that time, 76,626 newborn infants in Hiroshima and Nagasaki were examined by physicians employed by the Atomic Bomb Casualty Commission (ABCC), the predecessor of the present Radiation Effects Research Foundation."

While the physical examination of newborns provided information on a number of indicators of possible genetic effects, including the frequency of male births, birth weight and pre-maturity, occurrence of death during the neonatal period (defined as the first seven days following birth; see reference, page 33, for definition of neonatal death), and growth and development at age eight to ten months, attention here focuses solely on the occurrence of so-called major birth defects (Are birth defects more common among the children of atomic-bomb survivors? (http://www.rerf.or.jp/eigo/radefx/genetics/birthdef.htm)."

The Basics

Birth defects caused by exposure to radiation have been linked to genetics. Genetics are responsible for many things including eye color, hair texture, skin color, height, weight and other characteristics of what people look like (The Basics of Genetic Effects and Birth Defects (http://www.doh.wa.gov/Hanford/publications/overview/genetic.html).

These traits are based on information contained in the genes of the deoxyribonucleic acid (DNA), which are inherited at the time of birth. Genes are part of the 23 pairs of chromosomes found in human cells (The Basics of Genetic Effects and Birth Defects (http://www.doh.wa.gov/Hanford/publications/overview/genetic.html)." defect occurs when there are changes in the DNA. Changes can occur spontaneously or can be caused by an external factor. One of the external factors that has been strongly linked with changes in the elements of DNA is exposure to radiation. Changes that are caused or directly linked to the exposure to radiation are referred to as mutations.

When these changes result from radiation exposure they are called radiation-induced mutations (The Basics of Genetic Effects and Birth Defects (http://www.doh.wa.gov/Hanford/publications/overview/genetic.html)."

There are two types of mutations: germline and somatic. A germline mutation, or inheritable genetic effect, occurs when the DNA of a reproductive cell (sperm or egg) is damaged. Radiation-induced germline mutations may cause health problems which include miscarriages, stillbirths, congenital defects, premature death (death in the first year of life), chromosomal abnormalities and cancer in later life (The Basics of Genetic Effects and Birth Defects (http://www.doh.wa.gov/Hanford/publications/overview/genetic.html)."

When a health defect or problem is present when a person is born it is called a birth defect. When such a defect is caused by impairment to DNA because the mother or father was exposed to radiation before conception occurred it is called an inherited or a genetic birth defect caused by radiation.

Other birth defects may occur if a child was exposed to radiation during the mother's pregnancy. These birth defects include a reduction in height, severe mental retardation, small head size and impaired brain development, the latter of which may indirectly reduce an individual's intelligence quotient (IQ) and school performance (The Basics of Genetic Effects and Birth Defects (http://www.doh.wa.gov/Hanford/publications/overview/genetic.html)." cell can be harmed or changed any time a radiation active particle comes in contact with it. Whether the radiation hits the cell or a wave caused by the radiation contacts the cell can have one of four different outcomes occur:

It may pass through the cell without doing damage.

It may damage the cell, but the cell may be able to repair the damage before it produces new cells.

It may damage the cell in such a way that the damage is passed on when new cells are formed (The Basics of Genetic Effects and Birth Defects (http://www.doh.wa.gov/Hanford/publications/overview/genetic.html)."

It may kill the cell (The Basics of Genetic Effects and Birth Defects (http://www.doh.wa.gov/Hanford/publications/overview/genetic.html)."

Studies conducted on children whose fathers had been exposed to radiation before conception are important to the understanding of how radiation impacts genetic birth defects. One study reported an association between radiation doses received by the fathers and neural tube defects in the later born children. This held true even when the father had received a low dose of radiation, less than 10 rem) (The Basics of Genetic Effects and Birth Defects (http://www.doh.wa.gov/Hanford/publications/overview/genetic.html).

Other research suggests there is reason to believe that radiation exposure before pregnancy can increase the frequency of birth defects (The Basics of Genetic Effects and Birth Defects (http://www.doh.wa.gov/Hanford/publications/overview/genetic.html)."

Bombing exposure is not the only way one can create an environment for genetic birth defects due to radiation. Several research studies indicate that there is a provable relationship between X-ray exposure before birth and the later development of childhood cancer.

A large study by Alice M. Stewart (Senior Research Fellow, Department of Public Health and Epidemiology, University of Birmingham, England) and one by Brian MacMahon (Professor Emeritus, School of Public Health, Harvard University) each found an association between medical X-ray exposure before birth and childhood cancer. These findings indicate that the most sensitive period of exposure for developing leukemia is about the seventh month of pregnancy. The most sensitive period of exposure for developing all cancers, except leukemia, is the first six months of pregnancy (The Basics of Genetic Effects and Birth Defects (http://www.doh.wa.gov/Hanford/publications/overview/genetic.html)."

Children who were born after their mothers were exposed to bombing did have a higher incidence of brain tumors and mental retardation.

This was especially true for those women who were eight to 15 weeks pregnant at the time of exposure. Compared with non-exposed children, children exposed to whole-body radiation doses during this period before birth had lower intelligence test scores and performed less well in school (The Basics of Genetic Effects and Birth Defects (http://www.doh.wa.gov/Hanford/publications/overview/genetic.html)."

Another study conducted in Canada concluded that exposure to radiation places children at a higher risk for five different types of birth defects. There were other defects also attributed to radiation exposure but at a lower rate (Study finds increases in birth defects near CANDU reactor (http://www.antenna.nl/wise/361/3568.html).

Medical Name of Birth Defect Cases Observed in Pickering Cases Expected (@ Ont. rate) Statistical Significance (Poisson test)

1) Patau's syndrome 2-0.30-95%

2) Indeterminate sex and pseudohermaphroditism 2-0.25-95%

3) Cleft palate 4-1.13-95%

4) Cleft palate with cleft lip 4-1.08-95%

5) Anomolies of the spine 3-0.42-99%

6) Hyperchylomicronemia 1-1.01-99%

7) Other hyperlipidaemia 1-0.02-95% (Study finds increases in birth defects near CANDU reactor (http://www.antenna.nl/wise/361/3568.html)"

Additional research has shown that infant death rates…

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