Family history of plasma cell disorders is associated with improved survival in MGUS, multiple myeloma, and systemic AL amyloidosis.

The association between familial plasma cell disorders (PCD) and prognosis in patients with MGUS, multiple myeloma (MM), and systemic light chain (AL) amyloidosis has not been well described. This study retrospectively reviewed outcomes of 25,423 patients (16,744 MGUS, 6194 MM, 2955 AL amyloidosis). Overall, 2.7% of patients reported having a family member with a PCD (defined as MGUS, MM, or AL amyloidosis). Family history was documented in 94% of MGUS, 92% of MM, and 88% of AL amyloidosis patients. The overall survival was consistently longer in patients with versus without familial PCD (crude hazard ratios: 0.52, 95% CI 0.40-0.67, p < 0.001 for MGUS patients; 0.68, 95% CI 0.57-0.79, p < 0.001 for MM patients; 0.60, 95% CI 0.43-0.84, p = 0.003 for AL patients). This association remained consistent when adjusting for baseline patient and disease characteristics. In MGUS patients, the risk of progression to MM, AL amyloidosis, or a lymphoproliferative disorder was higher in patients with familial PCD when accounting for death as a competing risk (cause-specific HR 1.9, 95% 1.3-2.7, p < 0.001). This is the first study to demonstrate that in a cohort of MGUS, MM, and systemic AL amyloidosis, patients with a PCD family history have an improved overall survival.