Chronic and terminal illness has already become one of the key threats facing the developed world. The genetic mechanisms behind the development of many of these conditions have been extensively recognized. People in the western world are increasingly susceptible to the genetic risks of inherited disorders such as diabetes mellitus, breast cancer, and stroke. Unfortunately, not everyone is aware of these risks. Few people are ready to undergo genetic testing and learn how to reduce the risks of inherited conditions at different stages of their lifespan. Familial history is often the most reliable source of truthful information about inherited disorders, but even then family members may be reluctant to tell the entire story of their health and illness, thus creating obstacles to achieving higher levels of health and wellbeing for future generations.
After a brief review of my family and illness history, I have found colorectal cancer to be one of the key inherited health issues I may be facing later in life. To be honest, I did not expect it to be as serious as it is, but upon learning that some of my family members had a history of colon cancer, I immediately realized that I would need to consider this predisposition more closely. In fact, colon and colorectal cancers remain one of the principal causes of cancer mortality in the developed world. In 2003, Lynch and Chapelle estimated that at least 148,000 individuals would be diagnosed with colorectal cancer every year, and 56,600 would die. However, while the overall risks of developing colorectal cancer vary between 5 and 6 percent, every fifth adult diagnosed with this condition has a family history of this terminal illness (Lynch & Chapelle, 2003). Its symptoms vary widely, from unexpected or inexplicable changes in the bowel function to rectal bleeding, abdominal discomfort, weight loss and fatigue lasting for more than 4 weeks. Given the severity of the selected condition, every person should be in a position to investigate his or her family history and take steps to reduce his or her vulnerability to inherited diseases.
Here a distinction should be made between hereditary and familial patterns of inherited diseases. According to Rustgi (2007), hereditary colorectal cancer “connotes a distinct genetic basis that has been defined, whereas the latter [familial] comprises an increased predisposition to cancer but without determination” (p. 2526). In other words, hereditary colorectal cancer always follows the same genetic pattern and form, whereas familial cancer simply implies that another family member can develop its symptoms, but these will not necessarily coincide with the typology and syndromes diagnosed in other members of the same family. In my family, a clear line of hereditary colorectal cancer has been determined, with two family members being diagnosed with HNPCC (Lynch) syndrome at different moments of time. Rustgi (2007) says the mode of inheritance for Lynch syndrome is autosomal dominant, with an early onset and more than 80 percent lifetime risk for developing colorectal cancer. The autosomal dominant mode of inheritance suggests that patients with HNPCC display similar somatic genetic mutations that predetermine their susceptibility to the selected condition (Rustgi, 2007). It also means that the gene affected by mutations is a dominant gene, which is located on one of the nonsex chromosomes, and if a mother or a father has an autosomal dominant disorder, their children are 50 percent likely to have the same mutation and develop the same condition at some point of their lifespan.
The autosomal dominant inheritance of colorectal cancers, including HNPCC, has been extensively explored and recognized (Lynch & Chapelle, 2003; Rustgi, 2007). It was also detected in other forms of colon cancer, including polyposis and nonpolyposis ones. The Lynch syndrome is a nonpolyposis form of colorectal cancer, and when it becomes hereditary, it affects several generations and may even result in the development of several different forms of cancer simultaneously (Lynch & Chapelle, 2003). This hereditary syndrome is also responsible for a variety of extracolonic cancers (Lynch & Chapelle, 2003). The germ-line mutations of two different genes – MLH1 and MSH2 – cause almost 90 percent of nonpolyposis colorectal cancers, which is why nurses and physicians should screen their patients for MLH1 and MSH2 if they suspect a familial or hereditary pattern (Lynch & Chapelle, 2003).
Despite the wealth of information about the disease and its genetic characteristics, it is not enough to reduce the scope of cancer in families. To draw better conclusions about the disease, more information is needed about screening methods and preventative medicine. While gathering information about my family’s history, I encountered two barriers – reluctance of some family members to share information about their health with others, and failure to remember diagnoses, diseases, or symptoms experienced by the deceased members of our family. If I were to have a child, I would say honestly that our family has a history of colorectal cancers. However, I would also tell him or her that contemporary methods of screening can reduce the risks of developing this condition during the lifespan. I hope that future research will provide more information about the inheritability of colorectal cancers, including Lynch syndrome, thus enabling families to break the pattern of the disease and minimize its risks for future generations.
Overall, inherited diseases represent one of the greatest challenges for the healthcare system. The genetic mechanisms behind colorectal cancers have been extensively analyzed. The autosomal dominant mode of inheritance implies that every member of the family with a history of colorectal cancer has high chances to develop this condition. Unfortunately, family members are not always ready to share detailed information about their health. Future research is needed to understand how these genetic ties could be disrupted or broken to relieve the burden of inherited diseases on the future generations.
