HPRT1 and Lesch-Nyhan syndrome: Using HPRT-deficient human dopaminergic SH-SY5Y neuroblastoma cells as a model of Lesch-Nyhan disease, Guibinga et al. recently found that miR-181a down-regulates the expression of transcription factors relevant for dopaminergic development, i.e. EN1, EN2 and LMX1A [58].