More than two years ago, one of my father’s neurologists determined that Dad had low levels of B-1 in his blood, and said this was the major factor in his dementia. “We think iron overload causes B-1 deficiency,” he told me. “Genetic tests show he is an iron overload carrier – he has one copy of the C282Y mutation in the hemochromatosis gene that causes iron overload when present in two copies. Being a carrier is typically a silent condition, but it is not with your dad – he does have high levels of iron. Iron overload may be a factor causing his dementia.”
Did I inherit Dad's iron overload gene mutation along with his good looks?
This neurologist was not alone in thinking there might be a connection between the genes associated with iron overload or hemochromatosis and Alzheimer’s. The results of a University of Toronto study published in 2000 showed that these genetic mutations predisposed men to Familial Alzheimer’s Disease, but might actually be somewhat protective for women. Subsequent studies have had mixed results.
When I found the results of Dad’s hemochromatosis genetic test in his records, the write-up was so long and technical I couldn’t begin to interpret it. Two genetic mutations other than C282Y were listed: H63D and S65C. Did he have all three mutations?
I called the American Hemochromatosis Society for help, and they suggested I contact Kimball Genetics, Inc. a DNA diagnostic lab in Denver, Colorado. The company’s President and Laboratory Director, Dr. Annette Taylor, was kind enough to help me interpret Dad’s tests.
“There really is a lot of technical information in the report,” she said, “but the final interpretation is that your father was heterozygous (had a single mutation) for ONLY the C282Y mutation associated with iron overload. A double mutation is strongly associated with iron overload, but most heterozygotes have only slightly increased iron. Only about 1% of people with hemochromatosis have just this single mutation.”
“Other genes may also be involved in leading to iron overload in C282Y heterozygotes,” she continued, “but your dad was negative for the H63D and S65C mutations.”
Before I talked with Dr. Taylor, I sent a DNA sample to Kimball Genetics to see if I had the same mutation Dad had. I used their collection kit to swab the inside of my cheek, and sent the swabs to the lab. “Your genotype is fine,” she assured me. You got your Dad’s normal gene.”
Now that I have a copy of Dad’s blood test results, I’m not sure he really had high levels of iron anyway. I’ll talk more about that in my next post. In the meantime, it’s looking less likely to me that inherited iron overload caused his dementia.