Early and long-term effect of the treatment with pyridostigmine in patients with GMPPB-related congenital myasthenic syndrome

• Published in: Neuromuscular disorders : NMD 2020-09, Vol.30 (9), p.719-726
• Main Authors: Bobadilla-Quesada, Edna Julieth, Natera-de Benito, Daniel, Carrera-García, Laura, Ortez, Carlos, Exposito-Escudero, Jessica, Jimenez-Mallebrera, Cecilia, Jou, Cristina, Codina, Anna, Corbera, Joan, Moya, Obdulia, Saez, Veronica, Gonzalez-Quereda, Lidia, Gallano, Pia, Colomer, Jaume, Cuadras, Daniel, Medina, Julita, Yoldi, María Eugenia, Nascimento, Andrés
• Format: Article
• Language: English
• Subjects: Congenital myasthenic syndrome; Dystroglycanopathy; Gmppb; Motor functional scales; Muscular dystrophy; Pyridostigmine
• ISSN: 0960-8966; 1873-2364
• DOI: 10.1016/j.nmd.2020.07.009

•Patients with GMPPB-CMS responded dramatically to pyridostigmine in a few hours.•A moderate decrease in motor function was found after being treated during one year.•Nonetheless, motor function was still significantly better than before treatment.•Early treatment may have long-term effects such as preventing scoliosis development. GMPPB mutations cause congenital myasthenic syndromes (CMS) overlapping with muscular dystrophy. Treatment with pyridostigmine has been reported to be effective in those patients. Nevertheless, results of functional motor assessments to determine its precise impact on the short and long term were not available. We describe the response to treatment with pyridostigmine in three siblings with GMPPB-related CMS using functional motor scales performed regularly over a period of 40 months. The beneficial effect of the treatment was outstanding within the first hours, with all the scales showing a dramatic increase in only two days. This remarkable improvement remained steady during 12 months but a moderate decrease was subsequently detected in two of the three patients. Despite this decline in the scores of the scales at the end of follow up, the functional motor status of the patients was still significantly better than it was before starting treatment. The introduction of pyridostigmine at an early age of the disease in one of the patients, before the onset of scoliosis, may have had a protective effect on it.