Observations from a nationwide vigilance program in medical care for spinal muscular atrophy patients in Chile

ABSTRACT Spinal muscular atrophy (SMA) has gained much attention in the last few years because of the approval of the first intrathecal treatment for this neurodegenerative disease. Latin America needs to develop the demographics of SMA, timely access to diagnosis, and appropriate following of the standards of care recommendations for patients. These are essential steps to guide health policies. Methods This was a descriptive study of a cohort of SMA patients from all over Chile. We analyzed the clinical, motor functional, and social data, as well as the care status of nutritional, respiratory and skeletal conditions. We also measured the SMN2 copy number in this population. Results We recruited 92 patients: 50 male; 23 SMA type-1, 36 SMA type-2 and 33 SMA type-3. The median age at genetic diagnosis was 5, 24 and 132 months. We evaluated the SMN2 copy number in 57 patients. The SMA type-1 patients were tracheostomized and fed by gastrostomy in a 69.6 % of cases, 65% of SMA type-2 patients received nocturnal noninvasive ventilation, and 37% of the whole cohort underwent scoliosis surgery. Conclusion Ventilatory care for SMA type-1 is still based mainly on tracheostomy. This Chilean cohort of SMA patients had timely access to genetic diagnosis, ventilatory assistance, nutritional support, and scoliosis surgery. In this series, SMA type-1 is underrepresented, probably due to restrictions in access to early diagnosis and the high and early mortality rate.

摘要
脊髓性肌萎缩症（Spinal muscular atrophy, SMA）作为一种神经退行性疾病，随着首款鞘内治疗药物的获批，近年来受到广泛关注。拉丁美洲亟需完善SMA的流行病学数据、实现患者及时诊断，并严格遵循诊疗规范开展随访管理，这些均是指导卫生政策制定的关键环节。
方法 本研究为针对智利全国范围内SMA患者队列的描述性研究，分析了患者的临床、运动功能及社会人口学数据，同时评估了其营养、呼吸与骨骼系统的照护状况，并检测了该队列人群的运动神经元生存基因2（SMN2）拷贝数。
结果 本研究共纳入92例患者，其中男性50例；23例为1型SMA，36例为2型SMA，33例为3型SMA。三类患者在基因诊断时的中位年龄分别为5个月、24个月和132个月。本研究对其中57例患者的SMN2拷贝数进行了检测。69.6%的1型SMA患者接受了气管切开术并通过胃造瘘实施肠内营养支持；65%的2型SMA患者接受了夜间无创通气治疗；全队列中有37%的患者接受了脊柱侧弯矫形手术。
结论 1型SMA患者的呼吸照护仍主要以气管切开术为核心手段。本研究中的智利SMA患者队列能够及时获得基因诊断、呼吸辅助支持、营养支持及脊柱侧弯矫形手术治疗。本队列中1型SMA患者占比偏低，这可能与早期诊断途径受限以及早期高死亡率相关。