Based on multiple reaction monitoring, an eight-protein biomarker panel was identified (22 kDa protein, afamin, α-1 antichymotrypsin, apolipoprotein E, β-Ala His dipeptidase, haemoglobin α-2, isoform 1 of sex hormone-binding globulin, and peroxiredoxin 2), which was very specific and sensitive to diagnose male AFD patients. The gene discussed is APOE; the disease is Nager acrofacial dysostosis.