Abstract Details

Title Ophthalmoparesis as an Unusual Manifestation of Anti-HMGCR Antibody-related Myopathies

Topic Neuromuscular and Clinical Neurophysiology (EMG)

Presentation(s) P11 - Poster Session 11 (5:30 PM-6:30 PM)

Poster/Presentation
Number 11-007

Objective To describe two patients with anti-HMGCR antibodies, who developed limb-girdle and bulbar weakness, and ophthalmoparesis.

Background Ophthalmoparesis due to orbital myopathy is common in thyroid orbitopathy, mitochondrial myopathy, brachiocervical inflammatory myopathy (BCIM) and immune checkpoint inhibitor myopathy, but is not described in anti-HMGCR antibody-related myopathies.

Design/Methods Review of clinicoradiological and laboratory findings.

Results Patient 1 was a 53-year-old male who developed progressive proximal limb weakness, dysphagia, ptosis and diplopia over 6 weeks and creatine kinase (CK) of 3,512 units/L. Patient 2 was a 55-year-old female who had progressive proximal weakness, dysarthria, ptosis, diplopia and dyspnea over 2 weeks and CK of 31,998 units/L. Both patients had normal TSH and repetitive nerve stimulation, and myopathic motor unit potentials with fibrillation potentials in proximal and axial musculature. Patient 1 had normal single fiber EMG. Brain and/or orbit MRI displayed T2 hyperintensity in extraocular muscles in patient 1 and abnormal enhancement of extraocular muscles in both patients. Muscle biopsy showed rare necrotic and regenerating myofibers and a perimysial mononuclear cell collection, resembling cell foci described in BCIM, in patient 1 (deltoid), and scattered necrotic and regenerating myofibers without inflammation in patient 2 (quadriceps). Mitochondrial pathology was absent in both patients. Anti-HMGCR antibodies were present in both patients, who were on statins for several years. Anti-PM/Scl antibodies were borderline positive in patient 1 and negative in patient 2. Comprehensive cancer screening in both patients identified oropharyngeal squamous cell carcinoma in patient 1 only. Aggressive immunomodulatory therapies in both patients led to resolution of oculobulbar weakness and normalization of CK levels. Limb weakness resolved completely in patient 1 and partially in patient 2.

Conclusions

Our patients expand the phenotypic spectrum of anti-HMGCR antibody-associated myopathies. A syndrome of subacute ophthalmoparesis with limb-girdle weakness and severe hyperCKemia should not preclude a diagnosis of anti-HMGCR antibody-related myopathies.

Authors/Disclosures
Brendan Putko, MD, MSc PRESENTER	Dr. Putko has nothing to disclose.
Gregory P. Van Stavern, MD, FAAN (Washington University Ophthalmology)	Dr. Van Stavern has received publishing royalties from a publication relating to health care.
Alan Pestronk, MD, FAAN (Washington University in Saint Louis - Neurology)	The institution of Dr. Pestronk has received research support from Jain. The institution of Dr. Pestronk has received research support from Fulcrum. The institution of Dr. Pestronk has received research support from Argenyx. The institution of Dr. Pestronk has received research support from NeuroNext.
Cecile L. Phan, MD (Baylor College of Medicine)	Dr. Phan has nothing to disclose.
Grayson B. Beecher, MD (University of Alberta)	Dr. Beecher has nothing to disclose.
Teerin Liewluck, MD, FAAN (Department of Neurology, Mayo Clinic)	Dr. Liewluck has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sarepta Therapeutics. Dr. Liewluck has received publishing royalties from a publication relating to health care.

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