GJB2 and nodular sclerosis classical Hodgkin lymphoma: The protocol included: (1) an accurate clinical evaluation of all the patients and their relatives to exclude all the cases in which HL was due to non-genetic causes (i.e., middle ear anomalies, infections, ototoxic drugs, etc.)and to distinguish between NSHL and SHL; (2) the analysis of GJB2, GJB6 and MT-RNR1 genes in patients affected by NSHL; (3) the evaluation of STRC-CATSPER2 and OTOA deletions in case of negativity to step (2); (4) Whole Exome Sequencing (WES) analysis in case of negativity to steps (2) and (3) and for patients affected by SHL (Figure 1).