We previously reported a single patient with a complex adult‐onset mitochondrial disorder characterised by PEO and prominent cerebellar features, but without evidence of Bloom syndrome, resulting from bi‐allelic TOP3A gene variants (Nicholls et al, 2018); additional families have since been described (Llaurado et al, 2022; Primiano et al, 2022). Here, TOP3A is linked to Bloom syndrome.