Category: Genetics faqs

Some diseases are caused when there is a change in the instructions in a gene. This is called a mutation. Every person has many mutations. Sometimes these changes have no effect or are even slightly helpful. But sometimes they can cause disease.

Most common diseases are caused by a combination of mutations, lifestyle choices, and your environment. Even people with similar genes may or may not get an illness if they make different choices or live in a different environment.

Thousands of diseases are caused by a specific change in the DNA of a single gene. Many of these diseases are rare. These conditions usually develop when an individual is born with a mutated gene.

If a rare disease runs in your family, be sure to write it down. Do not forget to learn about common conditions that affect your family’s health.

Children inherit pairs of genes from their parents. A child gets one set of genes from the father and one set from the mother. These genes can match up in many ways to make different combinations. This is why many family members look a lot alike and others don’t look like each other at all. Genes can also increase the risk in a family for getting certain health conditions.

Families also share habits, diet, and environment. These influence how healthy we are later in life.

You share a lot with your family—including what can make you sick.

Genetics helps to explain:

• What makes you unique, or one of a kind
• Why family members look alike
• Why some diseases like diabetes or cancer run in families
• How learning your family health history can help you stay healthy
• Why you should bring your family health history to your healthcare provider

Taking time to learn about health and diseases that run in your family is worth it! It will help you understand your own health and make healthy choices.

During your appointment, you will meet with a genetic counselor. In some of our clinics, you will see a physician at the same time. The genetic counselor will review your personal medical history and will take a detailed family history, focusing on the cancers in your family. Based on this information, your genetic counselor will assess the likelihood for an inherited cancer gene mutation in your family. Your genetic counselor will provide information about basic genetics and explain the genetic test options that are relevant to you. He or she will review the risks, benefits and limitations of genetic testing, discuss the potential results, and obtain informed consent. Your genetic counselor will help you to make an informed decision about genetic testing. 

Some patients have found it helpful to put together a list of family members, showing which family members have had cancers, their ages at diagnosis, and any other relevant information, such as genetic testing results.

Please still come to your genetic counseling appointment. Many people have limited understanding of their family history for various reasons. The genetic counselor will be able to provide you with information regardless of how detailed your knowledge is.

Genetic counseling is a very important part of the genetic testing process and is essential at Mass General. The purpose of the genetic counseling session is to:

• assess the risk for hereditary cancer based on your family history
• provide education about genes and genetic testing
• discuss the risks, benefits, and limitations of genetic testing
• discuss what genetic testing means for you and your family
• make sure that the necessary procedures (mandated by state law) for informed consent are followed and
• make sure that the test is correctly ordered and interpreted

A genetic counselor is a health care professional with specialized graduate training in the areas of medical genetics and counseling. Genetic counselors work as a member of the healthcare team, providing information, facilitating decision making, coordinating genetic testing and giving support to patients and families who are at an increased risk to develop cancer. Genetic counselors help patients to manage their cancer risks by educating patients about medical management guidelines, and coordinating referrals to appropriate specialists.

Genes are made up by the DNA we inherit from our parents. We all have two copies of each gene (one from each parent). The DNA sequence of a gene is a code with instructions to make a functioning protein (like a recipe). Inherited changes to the DNA code can cause the gene to stop working. This prevents the protein from being made properly. Certain types of genes are responsible for controlling how cells grow. These genes help prevent cancer. People who inherit a mutation (change to the DNA sequence) in a gene that normally prevents cancer may have increased cancer risks.

You already know some of your single gene traits like the back of your hand. Specific versions of different single genes cause: hair growth on the middle segments of the fingers, the top of the little finger to bend dramatically to the ring finger, and determine whether the left thumb crosses over the right – or vice versa – when fingers are interlocked.

The result of other single gene traits are as plain as the eyes, ears, and hair on your face. People with blue eyes, non-dangly ear lobes or a straight hairline have inherited specific gene varieties. The ability to roll your tongue into a tube and also to taste certain bitter chemicals is also conferred by certain types of single genes.