We report the diagnosis of hereditary amyloidosis that affected a Belgian family that was initially diagnosed in a 73 year old woman. This patient was admitted with complaints of congestive heart failure. Cardiac work-up showed myocardial hypertrophy with zones of hyperintensity, suggestive for amyloidosis that was confirmed on a rectal biopsy. A hereditary form of amyloidosis was found by showing the Val30Met mutation within the transthyretin gene, that was also found in her asymptomatic son. This case shows that genetic testing is crucial in cases of unexplained amyloidosis and can help in the diagnosis and follow-up of patients and family members.