Fleshing out filaggrin phenotypes.

The association of filaggrin null alleles with eczema has been replicated in several European populations. Three large, well-conducted studies confirm this association and offer insights into the phenotypic nature of eczema associated with these alleles. Early data suggest that FLG-associated eczema may be more persistent, more likely to have palmar hyperlinearity, and more likely to be associated with asthma. These initial hints will require further confirmation in cohort studies.