Furthermore, molecular characterization of LCNEC and LCC has shown distinct mutational profiles with enrichment of RB1/TP53 mutations in LCNEC, while genomic alterations in SMARCA2, STK11, KEAP1, and MYCL1 were commonly detected in specimens from patients with LCC and LCNEC [34–40]. The gene discussed is SMARCA2; the disease is leukoencephalopathy with calcifications and cysts.