A. There is no clear evidence. There are a very small number of people world-wide who have a defective gene on chromosome 14 or 21 that causes Alzheimer’s disease with early onset, often between the ages of 35 and 60 years. Mostly Alzheimer’s disease affects older family members in a more random way.
Within our genetic make up some genes may be faulty and so cause certain diseases and conditions which can lead to inherited illnesses. Other differences in our genetic make up can give us a higher or lower risk of contracting an illness.