494 Epidermolysis bullosa pruriginosa, muscular dystrophy, and immune-mediated myasthenia gravis in a patient with homozygous nonsense PLEC mutation

A 26-year-old female presented with epidermolysis bullosa prurogompsa (EBP) since infancy, hair loss, proximal motor weakness, nasal tone speech, swallowing problem, and droopy eyes at age 20. Upon neurological examination, normal cognition, inability to walk unassisted, bilateral ptosis full range of extraocular movements, weak gag reflex, generalized muscle atrophy, decreased deep tendon reflexes were detected. Her electromyography revealed small polyphasic unit action potentials, minimal insertional activities, myopathic changes, sensory increased latency, amplitude, reduced velocity, F wave. These findings compatible myasthenia gravis (MG) muscular dystrophy. Acetylcholine receptor antibody test a titer 2.36 nmol/L (normal range: ≤ 0.4 nmol/L). Chest CT-Scan no thymoma or thymus enlargement. The serum creatine phosphokinase was 422 IU/L which higher than normal. Whole-exome sequencing disclosed homozygous PLEC variant (NM_000445.4: c.5533C>T; p.Gln1845*). Besides, biopsy staining Hematoxylin Eosin, modified Gomori Trichrome, Cytochrome c oxidase + Succinate dehydrogenase, Nicotinamide adenine dinucleotide, dehydrogenase-tetrazolium reductase showed chronic atrophic necrosis/ regeneration, internalization nuclei, severe endomysial fibrosis. pathological She treated stepwise incremental dose steroid up 30 mg/day for 6 weeks resulted in significant improvement her skin lesions addition ptosis. MG composite scale from 22 12. combination dystrophy immune-based EBP are novel this case.