[PMID 16550169] - loss of function mutations in FLG, most commonly rs61816761 (R501X) or rs558269137 (2284del4), carried by ~9% of Europeans, strongly predisposed for atopic dermatitis "highly significant association with asthma occurring in the context of atopic dermatitis".
3x risk of peanut allergy http://www.cbc.ca/news/health/story/2011/03/11/peanut-allergy-gene.html
[PMID 18049447] - FLG mutations (R510X and 2284del4 genotyped) assoc. w/ nickel sensitivity and nickel sensitivity combined with jewelery intolerance, but not with other contact allergens, in a 1,502 strong subset of the KORA C study group.
considerably more information is available elsewhere. see wikipedia, a glut of PubMed-listed papers, and the FLG OMIM entry