Serum concentrations of COL4A5 were higher in pre-BOS than in stable patients (40.5 ± 13.9 and 24.8 ± 11.4, respectively, p = 0.048), and lower in pre-BOS than BOS patients (40.5 ± 13.9 and 10.6 ± 3.34, respectively, p = 0.039) (Fig. 1a). This evidence concerns the gene COL4A5 and Buschke-Ollendorff syndrome.