It is also notable that family studies addressing ChT/CCL18/7-KC biomarkers in conjunction with the NP-C SI, filipin testing and subsequent gene sequencing led to the identification of a further three NP-C patients, and enabled the validation of two new causal NPC1 variants (p.(Arg1173Gly) and p.(Thr375Ala)). The gene discussed is SLC5A7; the disease is nasopharyngeal carcinoma.