Does it Run in the Family?

You’ve heard the saying. What does this really mean? Biologically-related family members share genes in common, and we can see evidence of this in the physical resemblance among many family members.

Families often also share much more than genetics.  Family members share their environment, dietary and exercise habits, lifestyle behaviors, and cultural practices. Most common health problems are a result of our genes interacting with the environment to cause disease.

Chronic health conditions like heart disease, diabetes, mental illness and certain cancers often have a familial component. In families where multiple closely-related biological family members have the same condition, there may be an increased risk for others to develop the same disease.

As you explore the donor catalog, there are some things you may want to keep in mind about family health history.

Ethnicity Matters

Compared with common health conditions that have complex causes, some genetic disorders occur with increased frequency in specific ethnic groups and are due to single-gene defects.  You are more likely to be a carrier for cystic fibrosis, sickle cell disease, or Tay-Sachs disease if you are a member of certain ethnic groups. Carrier testing is available for many of these conditions, and can help identify pregnancies at-risk for these diseases. If you learn that you are a carrier for a genetic disease, the ethnicity of the donor you select may have an impact on the likelihood of having a child affected by the disease. For more information on carrier testing for genetic diseases, click here.

Families are Unique

Nearly every family has health conditions that affect its members with increased or decreased frequency.  For example, a person in one family may be at greater than population risk for coronary artery disease, while being at lower than population risk for colon cancer. These risks are marginally increased or decreased from the background risk for all families, and all families have some risk. It’s useful to consider both sides of the family tree (yours and that of the donor you select) when evaluating the risk for disease.

Gathering the Information  

A person’s family medical history is most reliable when the information supplied is complete, accurate and up-to-date.  Optimally, the information gathered should include the name of the disease or condition, the family member who is affected, the age at diagnosis, how the condition was treated, and the outcome (disease resolved, is ongoing, resulted in death, etc). For those family members who are no longer alive, it is helpful to know how old they were when they died and the cause of their death.

In some families, complete health histories are hard to obtain because of privacy concerns, family members not being in contact, and/or certain cultural biases against sharing such information. Confidentiality should always be respected when gathering personal medical information.

TSBC donors are asked to provide health history information on their extended biological family members to the best of their ability. A board certified genetic counselor reviews all donor histories with the Medical Director and the Executive Director. Recipients are encouraged to explore their own family histories with their relatives and may want to ask their health care provider if they have questions or concerns about their family’s health problems.

Red Flags

Family medical history can help identify patterns in families that may be red flags.  For example, examination of the family medical tree can reveal clues that increase the likelihood that a health condition is hereditary.  These include:

  • Multiple family members with the same or related disorders
  • Earlier age of onset than typical
  • Conditions associated with intellectual impairment or developmental delay
  • Diagnosis in the less-commonly-affected sex
  • Bilateral disease (e.g., breast cancer in both breasts)
  • Conditions associated with one or more major birth defect
  • Disease in the absence of risk factors or after preventive measures
  • Growth abnormalities (asymmetry, under- or overgrowth)
  • Consanguinity (parents related by blood)

Conversely, health conditions are unlikely to be strongly genetic if they affect people in very old age, or if they are related to exposures such as heavy smoking or exposure to infectious agents or trauma.

Risk Assessment

Donor family health histories are evaluated for risk for disease transmission that exceeds the general population risk.  Those individuals with such histories are ineligible to be sperm donors.

For any interested individual, after the family history has been gathered and interpreted by a professional such as a genetic counselor, health recommendations can often be made. For common health problems, those who are identified as being at average or general population risk, standard public health recommendations apply: Maintain a healthy weight, don’t smoke, and get plenty of exercise.

If a history suggests that an individual is at above average or high risk for a disease or health problem, personal prevention measures and surveillance options can be employed after discussion with a physician. In high-risk families, some individuals will benefit from genetic testing.

Resources

To learn more about genetic health and about collecting your own family medical history information, visit the website of National Society of Genetic Counselors (NSGC)

Cynthia Kane, MS, CGC
Genetic Counselor
3/14/2014