Blog

Genetic testing for inherent disease | Part 4

shutterstock_26631571Every human has over 20,000 genes in nearly every cell of their body. A single gene disorder (SGD) is a disease that is caused by a known alteration or mutation in one of those genes. The disorder may be inherited through one or more generations in a family or inherited from both members of a couple who are carriers of the same condition. Part 4 in our genetic testing series takes a look at some commonly discussed inherited diseases and considers the question; ‘What’s the use of getting tested for diseases that have no cure?’

What are the inherited risks for cancer, Alzheimer’s, and other inherited diseases?

A person’s risk for developing these diseases is specifically based on their individual family history and ethnic background.  Speaking with a genetic counselor can help identify what diseases you may be at a higher risk to develop or pass on to your children. Genetic testing may further identify these inherent diseases you may be at risk to develop or pass on.

The Ashkenazi Jewish community have a high risk of carrying BRCA1 and BRCA2, which are associated with an increased risk of cancer. Which types of cancers fall into this category?

According the American College of Medical Genetics, individuals of Ashkenazi Jewish descent are at a higher risk of carrying some diseases including Tay Sachs and cystic fibrosis.  Roughly 1 in 4 or 1 in 5 Ashkenazi Jews will carry a mutation for one of these diseases.  All individuals with at least one grandparent who is Ashkenazi should be offered preconception screening for these inherited conditions.

BRCA 1 and 2 are well documented genetic mutations which place an individual at higher risk for cancer of the breast and ovary.  The National Institutes of Health estimates that roughly 25% of hereditary breast cancers are from BRCA1/2 mutations and roughly 5 to 10% of all breast cancers.  These mutations also account for roughly 15% of ovarian cancers.  These women may also be at risk for cancer of the pancreas and leukemia.  Men with the BRCA mutation may be at a higher risk of prostate cancer. (www.cancer.gov)

Tell me about people who carry the APOE- e4 (Alzheimer’s) gene?

APOE E4 is a gene that has been implicated in late onset Alzheimer disease.  This condition seems to run in some families making it likely to have some genetic component.  At present there are conflicting studies regarding this gene.  Not every individual who carries the gene will develop the Alzheimer disease.  Furthermore, absence of the gene does not mean that you cannot develop the disease.

Can anything be done for people who carry the APOE-e4 gene?

At present there is no early intervention which can prevent the progression of Alzheimer disease.  In general, testing for APOE-e4 is discouraged because it may add unwarranted psychological stress knowing you may develop the disease.

Can the deterioration of Alzheimer’s disease be slowed?

At present there are few interventions for Alzheimer disease.  Most medications are aimed at treating symptoms, but cannot slow progression of the disease.

What is the use of getting tested for diseases like Alzheimer’s that have no cures at this point?

Many diseases which do not have a “cure” can be better managed when they are identified at early stages.  Medications may be able to slow the progression of the disease, enabling individuals to live longer and improving their quality of life.  Knowing you are at risk to have a disease can allow physicians to screen and identify early symptoms allowing for early intervention.

GENETIC TESTING SERIES

Part 1 Common Questions Asked & Answered

Part 2 The Advantages & Disadvantages

Part 3 Advancing Technologies

Part 4 Inherent Disease



Dr. Thomas Molinaro, MD, MSCE, FACOG

Physician Partner, Reproductive Medicine Associates of New Jersey Eatontown, NJ

View more blogs by Dr. Molinaro or follow him on Facebook Twitter