Introduction Lesch–Nyhan syndrome (LNS; OMIM: 300322) is a rare neurogenetic disorder of purine metabolism caused by complete or severe deficiency of the enzyme HPRT1 (Seegmiller et al., 1967). The disease is transmitted in the X-linked recessive mode of inheritance and encountered in different populations including Arabs (Shaltiel et al., 1981; Torres and Puig, 2007; de Gemmis et al., 2010; Yamada et al., 2014; Nguyen et al., 2017; Cho et al., 2019; Li et al., 2022).