TTN and hydrops fetalis: LMNA truncating (nonsense/frameshift) → high arrhythmic risk; some missense (exons 7–12) VUS [32,33,34]. PLN p.Arg14del (in-frame deletion) → malignant VAs, risk model validated [35,36]. FLNC truncating → VAs, remodeling; some missense alter splicing/aggregation [37,38,39]. TTN truncating (frameshift, nonsense, splice-site) → common, milder arrhythmic profile, recovery possible [40,41]. BAG3 p.Pro209Leu (missense) → early DCM, HF progression, VAs [23]. TAZ loss-of-function (frameshift, nonsense, splice-site, insertion/deletion) → Barth syndrome [16]. SCN5A missense → arrhythmic DCM [15].