Results: Our results showed normal production of monocyte precursors and classical Mo (cMo) in MGUS, while decreased in SMM and MM (p ≤ 0.02), in association with lower blood counts of recently-produced CD62L+ cMo in SMM (p = 0.004) and of all subsets of (CD62L+, CD62L− and FcεRI+) cMo in MM (p ≤ 0.02). The gene discussed is SELL; the disease is Miyoshi myopathy.