The invention is directed to a method for non-invasive determination of the potential presence of one or more loss-of-function mutation(s) in the gene encoding for filaggrin. The method of the invention comprises (i) obtaining a vibrational spectrum from the stratum corneum of the individual； (ii) determining the local natural moisturising factor content from the vibrational spectrum； (iii) optionally repeating steps (i) and (ii)； and (iv) comparing the local natural moisturising factor content of the individual to a reference value, wherein said stratum corneum is stratum corneum of a location of the body of said individual at which said one or more loss-of-function mutation(s) in the gene encoding for filaggrin has a stronger influence on the natural moisturising factor concentration than other factors influencing the natural moisturising factor concentration.
