Clinical InvestigationGeneticsCardiac amyloidosis in African Americans: Comparison of clinical and laboratory features of transthyretin V122I amyloidosis and immunoglobulin light chain amyloidosis
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Patients
Patients who reported their ethnicity as African American and were seen between 1985 and 2009 in the Amyloid Clinic at Boston Medical Center were included. Informed consent for data and sample collection was obtained from patients with the approval of the Boston University Medical Campus Institutional Review Board. Clinical data included history, physical examination and laboratory studies of hematologic parameters and organ function. Tests for a plasma cell dyscrasia occurring in AL included
Identification of TTR V122I
Between 1985 and 2009, 156 African Americans (Figure 1) were evaluated for a diagnosis of amyloidosis. In 3 patients, amyloid disease could not be confirmed. Sera were tested for a TTR variant by IEF. Normally, one protein band corresponding to wild-type, monomeric TTR is detected; the occurrence of 2 protein bands indicates a variant TTR is present. We and others have previously shown that V122I has a lower pI than wild-type TTR (Figure 2, A).14, 18 In the present study, IEF screening
Discussion
This is the first report of a large series of African American patients with biopsy-confirmed amyloidosis and inheritance of TTR V122I. The study was designed to evaluate the occurrence of V122I and resulting ATTR in African Americans in a referral population. Although it is important to note that TTR V122I mutation carriers were identified retrospectively from blood samples in an amyloid clinic, the results show that the TTR V122I mutation was present in more than one fifth (36/156) of African
Acknowledgements
The authors are grateful to Pamela SooHoo and Brian Spencer for their excellent technical assistance.
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