I was wondering whether there exists relevant papers about the use of ACE model in small sample studies. More specifically, I am working on data collected on about 15 to 20 subjects (for each group of MZ/DZ) in a neuroimaging studies. The outcome of interest is actually related to morphometric quantitization, but this may evolve toward fMRI eventually.
Obviously, with such a small sample, we cannot make strong inference nor rely on asymptotic LR tests; so I use a permutation scheme (around zygoticity labels) to estimate sampling fluctuations of A/C/E components and get a p-value. I wonder if this makes sense in this context, and if you know of any papers that deal with this kind of underpowered studies and focus on robust methods to estimate A/C/E components and appropriate tests of ACE against AE/CE models. The only study relying on resampling that come to my mind is a technical report by Chiang et al., Mapping genetic influences on brain fiber architecture with high angular resolution diffusion imaging, although a different technique is used in Chiang et al. Genetics of brain fiber architecture and intellectual performance. The Journal of neuroscience 29(7): 2212-2224.