There are only two main categories of diagnostic tools in ATTR-PN: TTR gene sequencing looking for TTR gene amyloidogenic variants and tools for detection of amyloid deposits including classical biopsy and, more recently, bone scintigraphy with diphosphono-1,2-propanodicarboxylic acid (DPD), hydroxymethylene diphosphonate (HMDP), or pyrophosphate (PYP) (Table 3). Here, TTR is linked to poikiloderma with neutropenia.