A brain tumour-like episode led us to suspect RVCL and identify a mutation in TREX1 (p.L287fs).22 Another patient was diagnosed with pseudoxanthoma elasticum (PXE) based on skin biopsy and fundus findings, which confirmed a heterozygous compound mutation (p.Q378X and p.L1313fs) in ABCC6. The gene discussed is TREX1; the disease is brain neoplasm.