Heritability of Alzheimer's

1. Provide an estimate of h squared for the disorder. Based on this, discuss how much influence selection could have on this trait.
In a study, Heritability for Alzheimer's disease: the study of dementia in Swedish twins done in March of 1997, they wanted to find all cases of dementia in an established twin registry and to see what the heritability was for Alzheimer's. The study included sixty-five pairs of twins, both monozygotic and dizygotic twins, that either one or both of the twins had dementia. The concordance rate for monozygotic twins was 67 percent where as the dizygotic rate was 22 percent. According to this article, the estimated heritability for Alzheimer's is .74. The differences of when the onset of Alzheimer's came in the twins may be because of environmental factors. There is more known about the genetic effects of early onset Alzheimer's then known about late onset Alzheimer's. The influence of selection on Alzheimer's would not have a big impact because onset of Alzheimer's is after reproductive age. If there is a history of Alzheimer's in the family, a couple may choose not to have kids or adopt so that they would not be passing on the trait.

http://www.ncbi.nlm.nih.gov/pubmed/9060980- Heritability for Alzheimer's disease: the study of dementia in Swedish twins

2. What effect might inbreeding have on this disorder?
Since Alzheimer's has a heritability of .74, the effect of inbreeding may be substantial. The more inbred a population is, the higher the heritability could potentially be. The heterozygosity would go down, so there would be little variation in alleles.

Ashley Riles

Alzheimer's is a fascinating disease that is similar to many other diseases, which I learned that by studying similar diseases it may help find out how a certain one may progress. If Alzheimer's is linked to certain genes and another disease is also linked to some of those same genes then finding information about one could help the other whether the genes are inhertable or a mutation. If we find out what causes amyloid plaques in FFI, then we may figure out why they are in patients that have Alzheimer's. If doctors know about population genetics then they can provide patients the prevalence of the genetic diseases. It is helpful that docters know about evolution since diseases have changed and are continuing to change because of mutations, genetic drift, and natural selection. By studying how diseases and other pathogens have evolved in the past, helps to understand modes of reproduction, population structure, genetic variance, antibiotic resistence and virulence that may affect human body.

Grant Hengst

What I learned about our topic is that Alzheimers is a disease doctors are still working on to find more things about it. There is a huge search for the cure and since people are living longer now there is a higher percentage of elderly people getting Alzheimers. Also, I didn't know that there were high cholesterol drugs that were being looked at as a possible side effect of solving Alzheimers. I think a doctor should know about evolution because the knowledge of evolution furthers the understanding of the human body. If doctors would take an evolution course they could understand the concepts of mutation and genetic drift, which would help them greatly with understanding how some diseases start out as, for example Influenza (flu). Also, like Dr. Felzien said studying animal models and finding which animal was the best compared to humans would be a good evolution analysis to help doctors in curing diseases.