eLife assessment
Urofacial syndrome is a rare early-onset lower urinary tract disorder characterized by variants in HPSE2, the gene encoding heparanase-2. This valuable study demonstrates that AAV9-based gene therapy for urofacial syndrome is feasible and safe, at least over the time frame evaluated, with restoration of HPSE2 expression leading to re-establishment of evoked contraction and relaxation of bladder and outflow tract tissue, respectively, in organ bath studies. The evidence supporting these findings is solid, although the analysis would benefit from evaluation of additional replicates for several endpoints, quantitative assessment of HPSE2 expression, inclusion of in vivo analyses such as void spot assays or cystometry, more rigorous assessment of viral integration, and single-cell analysis of the urinary tract in mutants versus controls, all of which make the analysis of the data currently incomplete.