Abundant Nuclear Rods in Adult-Onset Rod Disease

Abstract

Abundant, highly organized, rod-shaped particles have been found in skeletal-muscle nuclei of two patients with adult-onset rod disease. They were usually single in affected nuclei. Like myofibrillar rods, the nuclear rods consisted of bundles of long, parallel, apparently cross-linked filaments. On longitudinal section the rods had an axial periodicity and in transverse section a wire-mesh appearance. Average periodicities were 189A (nuclear) and 178A (myofibrillar) axially, 180A (both) transversely between the longitudinal rod-filaments on longitudinal-section and cross-section of the rods. Minor differences were that the nuclear rods were slightly lighter stained after osmium-uranyl acetate-lead citrate, lacked thin filaments protruding from their ends, and often were broader. It is proposed that nuclear rods may have a contractile-protein composition and pathokinesis similar to that of myofibrillar rods. Their formation may reflect an epitomization of a newly recognized general biological capability of exogenous, or perhaps endogeneous, nuclear protein alteration.

Sporadic late-onset nemaline myopathy with monoclonal gammopathy of undetermined significance

“…Intranuclear rods, which are known to be associated with severe-infantile form of nemaline myopathy with ACTA1 mutation and relatively mild form with MYPN mutation, has been rarely reported [2,4,8,36]. It should be noted that NB per se is not specific although its presence is a mandatory finding of nemaline myopathies.…”

“…Through our literature search in PubMed until April 2017, we identified 31 SLONM-MGUS patients in 19 articles [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. On review of the cases, the disease usually appears in their late 30s or older (the median of onset age is 47 years old [range: 27 -78]).…”

“…SLONM with HIV infection and that with neither MGUS or HIV appear to be heterogeneous, although SLONM with HIV infection is usually responsive to corticosteroid, intravenous immunoglobulin (IVIg), and plasmapheresis [24,25,27,30]. On the other hand, SLONM with MGUS (SLONM-MGUS) patients show a particular phenotype: severe weakness and atrophy in axial, limb-girdle, and occasionally distal muscles, dysphagia, and respiratory insufficiency, which are often refractory to immunotherapy [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Of note, respiratory involvement is lethal, and the majority of the patients died within 1 to 5 years from the onset [8].…”

Clinical Reasoning: A 64-year-old man with progressive paraspinal muscle weakness

“…3 An association with monoclonal gammopathy was later reported by the same group. 4 In a large study on nemaline myopathy, 6 of 143 patients developed the disease in adulthood. These patients presented between the ages of 41 and 59 years.…”

Magnetic Resonance Imaging Findings of the Skeletal Muscle of a Patient with Nemaline Myopathy.

“…Nemalinemyopathyis a neuromuscular disorder characterized by muscle weakness and the presence of nemaline bodies (rods) in the muscle fibers, in the absence of other known conditions sometimes associated with rods (1), such as polymyositis, central core disease, chronic alcoholic myopathy, human immunodeficiency virus infection, congenital muscular dystrophy, multiple acylCoA dehydrogenase deficiency (2) and adult-onset rod disease (3). Reports of muscle magnetic resonance imaging (MRI) in nemaline myopathy are rare (4).…”