POLG and deafness-onychodystrophy syndrome: Neuropathological findings were reported for 16 patients (11 male; 73.3%) at median age 57 (range, 2–74) years: 22q11.2 deletion syndrome (n = 3), Down syndrome (n = 2), POLG (n = 2), BPAN (n = 1), CTX (n = 1), Cornelia de Lange syndrome (n = 1), DNAJC12 (n = 1), DOORS syndrome (n = 1), 5, 10‐methylenetetrahydrofolate reductase deficiency (n = 1), NR4A2 (n = 1), PPP2R5D (n = 1), and RAB39B (n = 1) (Table 2).