Carriers of loss-of-function mutations in the filaggrin (LoF FLG) gene have less natural moisturising factor (NMF) in their stratum corneum (SC) and an increased risk of atopic dermatitis (AD). NMF can be measured non-invasively by Raman spectroscopy. The use of Raman-derived NMF at birth to screen for FLG genotype could inform targeted AD prevention, but values in neonatal populations are largely unexplored.

<em>In-vivo</em> Raman spectroscopy discriminates between <em>FLG</em> loss-of-function carriers vs. wild-type in day 1-4 neonates:



Publication date: Available online 6 February 2020

Source: Annals of Allergy, Asthma & Immunology

Author(s): Carol Ní Chaoimh, Claudio Nico, Gerwin J. Puppels, Peter J. Caspers, X.F.Colin C. Wong, John E. Common, Alan D. Irvine, Jonathan O’B. Hourihane

Abstract

Background

Carriers of loss-of-function mutations in the filaggrin (LoF FLG) gene have less natural moisturising factor (NMF) in their stratum corneum (SC) and an increased risk of atopic dermatitis (AD). NMF can be measured non-invasively by Raman spectroscopy. The use of Raman-derived NMF at birth to screen for FLG genotype could inform targeted AD prevention, but values in neonatal populations are largely unexplored.

Objective

To examine the associations between Raman-derived neonatal NMF measurements and FLG genotype.

Methods

NMF was measured by Raman Spectroscopy in the SC of the thenar eminence within 4 days of birth in 139 term neonates. FLG genotyping was performed for 117 neonates (84%).

Results

The mean (SD) NMF was 0.37 (0.11) g/g protein, with values increasing across the first three days [Day 1 vs. 3: 0.29 (0.09) vs. 0.43 (0.08, P <0.001]. Twelve infants (10.3%) were carriers of LoF FLG, all heterozygous. NMF was lower in LoF FLG carriers compared with wild type [0.27 (0.08) vs. 0.38 (0.11) g/g protein, P ≤0.001]. NMF had good discriminatory power for FLG genotype [area under the receiver operating curve (AUROC): 0.79, 95% CI: 0.66, 0.91, P ≤0.001]. This improved after correcting Day 1 and 2 measurements to Day 3 [AUROC: 0.83, 95% CI: 0.75, 0.92, P <0.001].

Conclusion

This study suggests that Raman-derived NMF measured in the early postnatal period may have the potential to classify by FLG genotype. The full translational value of this needs to be determined.