A duplication of part of chromosome 15q, apparently inherited in a non-Mendelian fashion, has been found to be strongly associated with phobic disorders. This unusual genetic mechanism may partly explain the heritability of phobias and other complex traits.
Flint, J. (2001, November 13). Psychiatric genetics: A frightful chromosome. Current Biology. Cell Press. https://doi.org/10.1016/S0960-9822(01)00551-6