Anti-PL12 Anti-Synthetase Syndrome and Amyotrophic Lateral Sclerosis: A Case Report of a Rare Comorbidity

BACKGROUND Anti-PL-12 syndrome is a rare form of myositis. Amyotrophic lateral sclerosis (ALS) is the commonest of the motor neuron disorders. However, the 2 conditions have not been reported to occur together in a single individual. This case report describes a patient who was diagnosed with anti-PL-12 anti-synthetase syndrome and then subsequently was diagnosed with ALS. CASE REPORT A 55-year-old male patient had anti-PL-12 syndrome and ALS occurring together. The patient initially presented with musculoskeletal complaints and was diagnosed with anti-PL-12 syndrome. He later went on to develop shortness of breath. Neurophysiological testing subsequently confirmed ALS as the patient experienced worsening muscle weakness over a 2-year period. A muscle biopsy performed showed neurogenic and myopathic process. The patient eventually lost the ability to ambulate without mobility assistance and suffered cardiac arrest due to complications from ALS, specifically diaphragmatic dysfunction. CONCLUSIONS This case report represents the first documented case of a patient having both anit-PL-12 syndrome and ALS together. It has been suggested that having an autoimmune disease (AID) may increase the subsequent risk of developing ALS. Previous studies did not conduct evaluation to ascertain serological markers for AS antibodies. Lab tests were rechecked and revalidated multiple times in separate facilities for confirmation of results in case of initial lab error. This may suggest a common etiology for both anti-PL-12 syndrome and ALS.