TYR and alopecia: The KIT gene plays an important role in the development of ICCs, pigment cells, and mast cells.12,13 As a tyrosine kinase inhibitor, the inhibitory effect of imatinib on c-KIT is likely to lead to inhibition downstream of the promoter of the tyrosinase gene, thereby inhibiting the production of pigment and resulting in changes in hair color and skin tone.14 The proband’s sister (II-1) experienced slight alopecia after using imatinib, which was considered an adverse reaction of imatinib.