Question

what types of information obtained from the genogram inform the understanding of the pathophysiology of a disease in an individual? give an example. describe the relationship of genetics to cancer. give an example of a genetic contribution to cancer with recommendations for screening family members.

Answer 1

GENOGRAM

is a pictorial display of a person's family relationships and medical history. It goes beyond a traditional family tree by allowing the user to visualize hereditary patterns and psychological factors that punctuate relationships.^[1] It can be used to identify repetitive patterns of behavior and to recognize hereditary tendencies.Genograms are now used by various groups of people in a variety of fields such as medicine, psychiatry, psychology, socialwork, genetic research, education, and many more.

GENOGRAM DIAGRAMS OF OCCURANCE OF DISEASE

How to create a medical genogram

A medical genogram, is a special type of genogram that includes graphical representations of medical conditions, such as: age, cause of death, hereditary traits, and any additional information that can be used to access disease risk.

Genes and noncommunicable diseases

Most diseases involve many genes in complex interactions, in addition to environmental influences. An individual may not be born with a disease but may be at high risk of acquiring it. This is called as genetic predisposition or susceptibility. The genetic susceptibility to a particular disease due to the presence of one or more gene mutations, and/or a combination of alleles need not necessarily be abnormal.

FAMILY GENOGRAM AND PATHOPHYSIOLOGY OF A DISEASE( DIABETICS AS AN EXAMPLE)

• In this picture we can see2nd generation parents father is a healthy male and mother is diabetic
• they had 3 children two male and one female in that female and one male is diabetic , transfer the diabetic gene from mother to child.
• other male is a carrier of diabetic gene but not diabetic
• they all are married to a diabetically healthy spouse ( non diabetic) and had childresns
• the first family where healthy male married to diabetic female had two male , the first son is diabetic from his mother gene and the second son is not diabetic from healthy father gene
• in second family male carrier and healthy female had two children . one male is a healthy ( not having diabetis ) and duaghter  is diabetic. she become diabetics from his father ( his father is a carrier of diabetic gene fron his mother )
• the third family diabetic male married to healthy female had three childrens two female and one male . in that one female is a carrier of diabetic gene and non diabetic. others two ; one male and one female both are diabetics from his father gene.

CANCER AND GENETICS

Understanding genetic predisposition to disease and knowledge of lifestyle modifications that either exacerbate the condition or that lessen the potential for diseases (i.e., no smoking or drinking) is necessary for the public to make informed choices. This section on genetic predisposition to disease aims to provide descriptions of major diseases that have a genetic predisposition

Cancer

Cancer occurs because of mutations in the genes responsible for cell multiplication and repair. The changes which a cell undergoes in the process of malignant transformation is a reflection of the sequential acquisition of these genetic alterations. This multi-step process is not an abrupt transition from normal to malignant, but may take over 20 years or more. The mutation of critical genes, including supressor genes, oncogenes and genes involved in DNA repair, leads to genetic instability and to progressive loss of differentiation. Tumours enlarge because cancer cells lack the ability to balance cell division by cell death (apoptosis) and by forming their own vascular system (angiogenesis) . The transformed cells lose their ability to interact with each other and exhibit uncontrolled growth, invade neighbouring tissues and eventually spread through the blood stream or the lymphatic system to distant organs.

Prevalence:

According to the 2002 World Health Report, about 7.1 million deaths are attributed to cancer each year. The most prevalent of these cancers include lung, stomach, colon, liver, breast and oesophagus cancer, in that order of occurrence. Combined, these cancers are responsible for over 4.2 million deaths. Furthermore, according to the World Cancer Report (IARC 2003) deaths due to cancer will increase by 50% in the next 20 years. Even though generally considered as an illness of the developed countries cancer is a world wide health problem. In 2000 54% of new cancer cases occurred in developing countries. Due to demographic changes and changes in life style this percentage is expected to rise in the near future.

Diagnosis / prognosis:

The roles that genes play differ greatly, ranging from genes that completely determine the disease state ( disease genes) to genes that interact with other genes and environment factors in causing cancer (susceptibility genes).

Studies have shown that the primary determinants of most cancers are lifestyle factors, such as tobacco, dietary and exercise habits, environment carcinogens and infectious agents, rather than inherited genetic factors. In fact, inherited cancer syndromes caused by high penetrance genes transmitted In fact, the proportion of cancers caused by high penetrance genes is low, about less than 5% for breast cancer and less for most other cancer types except retinoblastoma in children.

Inherited mutations of the BRCA 1 gene account for a small proportion of all breast cancers, but affected family members have a greater than 70% lifetime risk for developing breast cancer or ovarian cancer. Identification of a germline mutations by genetic testing allows for preventive measures, clinical management and counselling. Since the prevalence of germline mutations such as BRCA1 is very low in most societies, the introduction of mass screening to identify people at risk to develop cancer is not recommended.

It is now appreciated that so-called metabolic polymorphisms, that is differences in the way people metabolize chemical carcinogens, explain differences in the susceptibility of individuals to cancer, and that these are controlled in cells by mutations in specific genes. A major research endeavour is now under way to characterize these genetic polymorphisms. It is already clear that there are a multiplicity of such genetic changes, that they are caused by genes of low penetrance, and that the classic Mendelian laws do not apply. However, it seems likely that collectively they explain much of innate susceptibility to cancer, and that therefore their potential contribution to the occurrence of cancer is large. It may eventually be possible to identify those individuals at special risk of tobacco or diet-associated cancers, and also those susceptible to the effects of environmental contaminants.

It is also anticipated, but not yet shown, that genetic tests may eventually provide information that will be used to determine the best course of treatment for some cancers. Some cancers currently classified as a single disease may ultimately be classified into different types, each best managed by a different therapeutic strategy.

In conclusion genetics may eventually play an important role in the control of cancer, including:

• identification of individuals at risk for a specific cancer, leading to preventive or screening strategies for an individual or family members.
• identification of the subtype of a cancer so that treatment can be tailored to target that specific disease.

1. from the predigree we can easily understand the cancer gene travel history .
2. after breast cancer female mother the gene went to her daughter with ovarian cancer
3. the male son generation was free from cancerous gene niether affected nor carrier
4. female daughter got married and it goes to one of her twin female and single male
5. after marriage of male, he got three childrens ; in that one female child got cancer from her father gene