According to the National Institutes of Health (2010), the Human Genome project began after Watson and Crick discovered the helix structure of human deoxyribonucleic acid (otherwise known as DNA) in 1953. From this point forward, the study of DNA has advanced with researchers setting out to map the human genome. Specifically, in 1990 the National Institutes of Health, together with the Department of Energy sought out to sequence all three billion letter of the human genome (National Institutes of Health, 2010). This was an international effort, with the United States partnering with the United Kingdom, France, Germany, Japan and China in this vast endeavor. In general terms, a genome is the set of DNA belonging to a single organism. Importantly, DNA molecules are made of two strands of chemical units that link. The bases are adenine, thymine, guanine, and cytosine. Within these strands, adenine always pairs with thymine, while cytosine always pairs with guanine. Those who volunteered to donate their blood became part of the project, and not everyone’s blood was used, so volunteers would not truly know if their blood was part of the database. In terms of the final project, the human genome is completely mapped, however, there are some small gaps that technologies have not been able to address. The gene-containing portion of this large database is available for public use, and it has allowed for extensive research that has shed light on unique genetic conditions.
According to the National Institutes of Health (2013), Trisomy 13 is a condition related to altered genetics/genetic abnormality. This condition, also known as Patau syndrome is a chromosome disorder in which the affected individual is severely intellectually disabled, and he or she may have physical abnormalities as well. For example, individuals may have heart defects, brain abnormalities, very small eyes, extra digits, and a cleft lip. Many infants with this condition die in the early days of life, but 5% to 10% of those with this condition live past their first year of life.
Another genetic abnormality is cystic fibrosis (National Institutes of Health, 2010). This is the most common, fatal genetic condition in the country. For those born with the condition, the disease leads the body to make excess mucus that fills the lungs, leading to infection. This in turn blocks the pancreas, and thus blocking digestive enzymes from reaching the intestine. Interestingly, only a single gene mutation can lead to the development of this disease. Specifically, alteration to the Cystic Fibrosis Transmembrane Regulator (CFTR) leads to this condition.
Finally, cri du chat is an interesting genetic condition caused by a deletion of genetic information on the arm of chromosome five. Although the specific cause of the deletion is unknown, the disease has a number of interesting presentations that can vary per individual. Given the name of the condition, it is not surprising that one of the symptoms is the presence of a high-pitched cry (similar to that of a cat). In addition, those with the condition typically have an intellectual disability or a developmental delay. Physically, these individuals tend to have a small head (in proportion to the rest of the body), and widely spaced eyes. Prominent within this condition are language disabilities. While some are able to learn to communicate in short sentences, others with this condition are unable to express themselves. Those with the condition tend to be agreeable, friendly, and generally unaware of their deficits (they are generally rather happy). Surprisingly, many of the cases of this condition that have been studied to date do not have a genetic link to the parents, which is intriguing since the cause of the deletion is unknown.
- National Institutes of Health (2013). Trisomy 13. Retrieved from: https://ghr.nlm.nih.gov/condition/trisomy-13
- National Institutes of Health (2010). Human Genome Project. Retrieved from: https://report.nih.gov/NIHfactsheets/ViewFactSheet.aspx?csid=45&key=H#H
- National Institutes of Health (2010). What was the Human Genome Project and why has it been important? Retrieved from:https://ghr.nlm.nih.gov/primer/hgp/description