We have several toe-walkers in my family: my sister, myself, and at least one of my sister's sons to name a few. We may be somewhat dysfunctional in other ways, but I haven't noticed anything that might be related to toe-walking. For us, it probably is a sensory thing. We seem to have other sensory sensitivities as well. Everyone said my sister and I would outgrow it, and we still haven't at 40+. I tell people it's the ballerina in me trying to get out, or else wear high heels. :-)