In independent studies of such patients, McKay et al. [42] and Herbst et al. [43] diagnosed NP-C in 1/228 (0.4%) and 1/6 (16.7%) subjects using custom-designed gene panels targeting NPC1/NPC2 alongside other genes associated with cholestatic disease in infancy and childhood. This evidence concerns the gene NPC1 and nasopharyngeal carcinoma.