August 28, 2017
Last week, 23andMe released two new genetic health risk reports for customers.
Taken together, 23andMe’s Genetic Health Risk reports remain the only direct-to-consumer genetic health reports authorized by the FDA. They can tell you about genetic variants that may increase your risk of developing certain serious health conditions, such as late-onset Alzheimer’s disease and Parkinson’s.
The two new reports focus on two other conditions: Age-related macular degeneration (AMD), and Hereditary Hemochromatosis. AMD is a leading cause of irreparable vision loss and blindness in older Americans. Hemochromatosis, which is a genetic condition characterized by the absorption of too much dietary iron, can lead to iron overload and which in turn can cause damage to the liver, heart, and pancreas.
These reports look at genetic variants with well-established and meaningful effects on risk.
Age-related Macular Degeneration
Our new report on AMD looks at the two most common variants associated with the risk of developing the condition — Y402H and A693.
There are two kinds of AMD— Dry AMD, which progresses more slowly and is milder, and it accounts for about 90 percent of all cases; and Wet AMD, which is more severe, progresses rapidly and accounts for the remaining cases.
A common symptom as AMD progresses is the development of a blurred area near the center of vision. Over time, the blurred area may grow larger or individuals may develop blank spots in their central vision. In addition objects may be less bright as the condition progresses.
Genetics plays a major role in developing both forms of AMD, although other factors also influence the risk, including diet, smoking, age, ethnicity (this report is most relevant to people of European ancestry) and exposure to sunlight. Lifestyle changes, like eating more leafy green vegetables, wearing sunglasses, and not smoking, can help reduce the risk of AMD.
While there are no treatments that can successfully reverse the damage from AMD, there are treatments that can help slow its progression. Researchers are looking to see if genetics influences the effectiveness of some of these treatments, such as the use of the injectable drug ranibizumab.
The 23andMe Genetic Health Risk report for Hereditary Hemochromatosis covers the most common forms of the condition caused by variants in the HFE gene. The HFE gene contains instructions for making a protein that helps to regulate the amount of iron absorbed into the body. The two genetic variants used in 23andMe’s report — C282Y and H63D — cause 91 percent of all HFE-related hereditary hemochromatosis. But, having these two variants doesn’t mean one will develop the condition.
Hemochromatosis tends to develop in older men, and it is most common with men of European ancestry. Women rarely develop the condition. With sometimes-vague symptoms that include fatigue, joint pain, and darkening of the skin, hemochromatosis can be hard to diagnose without genetic testing, such as this. But it is very treatable — often by regular blood draws — and if caught early, lasting damage to the liver, heart or other organs can be prevented.