A serendipitous journey to a promoter variant: The c.‐106C>A variant and its role in late‐onset ornithine transcarbamylase deficiency

Ornithine transcarbamylase deficiency (OTCD) is an X-linked urea cycle disorder characterised by reduced or absent OTC enzyme activity, resulting in the accumulation of neurotoxic ammonia. Approximately 80%-90% of the causative variants are identified by Sanger sequencing or multiplex ligation-dependent probe amplification (MLPA) of the