title: Familial (ATTR) amyloidosis misdiagnosed as the primary (AL) variant: a case report.
abstract: BACKGROUND
  Primary (AL) Amyloidosis is arguably the most recognizable variant of the disease with many classic signs. However, it has been argued that the Familial variant (ATTR) is actually more prevalent. It is less recognizable, however, as its spectrum of organ involvement is frequently much more limited. The two variants carry significantly different prognoses, have divergent treatment strategies, and very different implications for the family members of patients. There is now a small amount of data that would suggest Familial Amyloidosis may be misdiagnosed as the AL form 2-4% of the time as a result of laboratory error.
  
  
  METHODS
  Herein a case of Familial Amyloidosis initially mistaken for the AL form based on a false positive laboratory result is presented. This case illustrates the high index of suspicion required for proper diagnosis of this rare disease.
  
  
  CONCLUSIONS
  Clinician awareness of the various forms of Amyloidosis and the potential for lab error is key to ensuring an accurate diagnosis. The two most common forms carry significantly different implications for treatment and for potential impact on relatives. A high index of suspicion is required particularly for the Familial form of Amyloidosis.
authors.affiliation: Division of Cardiology, University of Colorado, Denver, Denver, CO, USA.
authors.forename: Philip B
authors.initials: PB
authors.lastname: Dattilo