Noteworthy Cardiovascular Involvement with Sporadic Late-onset Nemaline Myopathy

Matsuzono, Kosuke; Kumutpongpanich, Theerawat; Kubota, Ken; Okuyama, Takafumi; Furuya, Koji; Yagisawa, Tomoya; Horikiri, Akie; Igarashi, Takeshi; Miura, Kumiko; Ozawa, Tadashi; Mashiko, Takafumi; Shimazaki, Hideyuki; Koide, Reiji; Tanaka, Ryota; Shimizu, Hayato; Imai, Yasushi; Kario, Kazuomi; Nishino, Ichizo; Fujimoto, Shigeru

doi:10.2169/internalmedicine.6068-20

Cited by 2 publications

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References 19 publications

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“…11 Mild involvement of facial and bulbar muscles was observed only in 1 and 3 individuals, respectively, which was less common than that of other reports. 11 Although several reports indicated that the pulmonary and cardiac involvement in SLONM was the leading cause of death, 10,17-19 none of our patients had subjective symptoms or objective evidence indicating cardiopulmonary dysfunction. Generally, a combination of myogenic changes with spontaneous activities on EMG examination is more common in necrotic myopathy, such as myositis or muscular dystrophy, in which the CK level is always remarkably elevated.…”

Section: Discussionmentioning

confidence: 59%

Clinicopathologic Profiles of Sporadic Late-Onset Nemaline Myopathy

Zhao

Dai

Zhao

et al. 2022

Neurol Neuroimmunol Neuroinflamm

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Background and ObjectivesSporadic late-onset nemaline myopathy (SLONM) is a treatable or otherwise fatal myopathy. Diagnosis of SLONM is still challenging, and no therapeutic consensus has been achieved. Here, we reported the clinicopathologic features and long-term follow-up data of SLONM in a Chinese cohort.MethodsWe performed a retrospective evaluation of clinical, pathologic, and treatment outcomes of 17 patients with SLONM diagnosed between March 1986 and April 2021 at our neuromuscular center. Immunohistochemistry (IHC) with antibodies against 5 Z-disc–associated proteins was performed in the muscle biopsies of SLONM to identify a potential pathologic marker in aid of diagnosis. In comparison, we also performed muscle IHC in patients with selective type II fiber atrophy (n = 22), neurogenic atrophy (n = 22), mitochondrial myopathy (n = 5), immune-mediated necrotizing myopathy (n = 5), and normal controls (n = 5).ResultsMost of the patients exhibited asymmetric limb muscles weakness (71%, 12/17) and neck extensor weakness (53%, 9/17). Immunofixation electrophoresis was performed in 11 patients, and 4 of them were identified with monoclonal gammopathy of undetermined significance (MGUS). EMG from 16 patients demonstrated a myopathic pattern with spontaneous activities in 69% (11/16) of them. Muscle MRI showed preferential involvement of paraspinal, gluteus minimus and medius, semimembranosus, and soleus muscles. Suspected nemaline bodies on modified Gomori trichrome were confirmed by IHC using anti–α-actinin antibody (100%, 17/17), anti-myotilin antibody (94%, 16/17), anti-desmin antibody (94%, 16/17), anti–α-B crystallin antibody (65%, 11/17), and anti-telethonin antibody (18%, 3/17) with various positive rates. Notably, anti–α-actinin IHC showed the highest percentage of strongly positive staining (77%, 13/17), being the only one without negative results. Moderate improvement following autologous stem cell transplantation (ASCT) was noted in 3/4 patients with MGUS; favorable outcomes were also achieved in 6/7 patients without MGUS, including 3 patients with complete recovery who were given a combined treatment of prednisone and another immunosuppressant.DiscussionSLONM is a treatable myopathy with ASCT or traditional immunotherapy, especially when combined with steroids and immunosuppressants. Anti–α-actinin immunostaining is the most reliable pathologic marker to identify rod-bearing fibers, and it should be performed routinely in adult patients with undiagnosed nonnecrotic myopathies.

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