Hi there,
I am working with twin data. My current analysis involves data that has a lot of variation, and I am using small numbers n=90 MZ twins and n=48 DZ twins. I am working off a univariate ACE script and I am getting the CE model as the best fit for variables where the MZ correlation is significantly higher than the DZ, I would expect some heritable component.
I have seen a paper (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3202796/) which has similar numbers and looking at similar data. They say they are not powered to present A and C individually, and instead present A and C combined as one familial component. They also incorporate D into their model.
I have two questions.
Firstly, should I be combining A and C into familial component?
Second question can D be incorporated into this model to make and ADCE model. I am working with twins reared together and have never seen this before.
Thanks,
Rebecca