Suggested diagnostic approach and fat tissue biopsy procedure in patients with suspected systemic amyloidoses according to gender, organ involvement, and involved light-chain isotype. Genetic testing for hereditary amyloidosis is indicated in patients with isolated cardiac (to exclude TTR and apolipoprotein A1 amyloidoses) or renal (for fibrinogen and lysozyme) involvement, as well as in those with peripheral neuropathy, either isolated or associated with cardiac involvement (TTR). LC, light chain.