In Europe and the Americas, a relatively small number of DPB cases have been reported in Asian immigrants and residents, as well as in individuals of non-Asian ancestry.[26][27][28] Misdiagnosis has occurred in the West owing to less recognition of the disease than in Asian countries. Relative to the large number of Asians living in the west, the small number of them thought to be affected by DPB suggests non-genetic factors may play some role in its cause. This rarity seen in Western Asians may also be partly associated with misdiagnosis.[7][29]