Childhood eczema prevalence in New Zealand using topical corticosteroid dispensing data.

OBJECTIVES: To determine the prevalence of eczema among children in New Zealand. METHODS: Population-based retrospective observational study utilising national pharmaceutical dispensing records for topical corticosteroids and emollients for all New Zealand children aged 0-14 years from 1st January 2006 to 31st December 2019. Data are reported using descriptive statistics, with comparisons between ethnicities and socioeconomic quintiles undertaken with rate ratios. RESULTS: Based on dispensing data, the prevalence of eczema for New Zealand children aged 0-14 years in 2018 was 14.0% (95% CI 14.0%-14.1%), with prevalence decreasing in older age groups (children aged <1 year 26.0% (25.6%-26.4%); children aged 10-14 years 8.8% (8.7%-8.9%)). Prevalence was higher in Pacific children (23.6% (23.3%-24.0%)), but slightly lower in Maori children (13.2% (13.0%-13.3%)). CONCLUSION: Eczema is a common condition affecting a considerable proportion of children in New Zealand. This study provides nationwide paediatric prevalence data for New Zealand, and highlights the increased burden of eczema in Pacific children. Inequity in dispensing of topical corticosteroids is postulated to explain the reduced rates found for Maori children compared to previous studies. These results support the need for further research to determine factors contributing to differing eczema prevalence rates in New Zealand.

Highly efficient CRISPR/Cas9-mediated exon skipping for recessive dystrophic epidermolysis bullosa.

Gene therapy based on the CRISPR/Cas9 system has emerged as a promising strategy for treating the monogenic fragile skin disorder recessive dystrophic epidermolysis bullosa (RDEB). With this approach problematic wounds could be grafted with gene edited, patient-specific skin equivalents. Precise gene editing using homology-directed repair (HDR) is the ultimate goal, however low efficiencies have hindered progress. Reframing strategies based on highly efficient non-homologous end joining (NHEJ) repair aimed at excising dispensable, mutation-harboring exons offer a promising alternative approach for restoring the COL7A1 open reading frame. To this end, we employed an exon skipping strategy using dual single guide RNA (sgRNA)/Cas9 ribonucleoproteins (RNPs) targeted at three novel COL7A1 exons (31, 68, and 109) containing pathogenic heterozygous mutations, and achieved exon deletion rates of up to 95%. Deletion of exon 31 in both primary human RDEB keratinocytes and fibroblasts resulted in the restoration of type VII collagen (C7), leading to increased cellular adhesion in vitro and accurate C7 deposition at the dermal-epidermal junction in a 3D skin model. Taken together, we extend the list of COL7A1 exons amenable to therapeutic deletion. As an incidental finding, we find that long-read Nanopore sequencing detected large on-target structural variants comprised of deletions up to >5 kb at a frequency of ~10%. Although this frequency may be acceptable given the high rates of intended editing outcomes, our data demonstrate that standard short-read sequencing may underestimate the full range of unexpected Cas9-mediated editing events.