Abstract:
Spinal muscular atrophy (SMA) is an autosomal recessive condition characterized by alpha motor neuron degeneration in the spinal cord anterior horn. Clinical symptoms manifest in the first weeks to months of life in the most severe cases, resulting in progressive symmetrical weakness and atrophy of the proximal voluntary muscles. Approximately 95% of SMA patients present with homozygous deletion of the SMN1 gene. With multiple available therapies preventing symptom development and slowing disease progression, newborn screening for SMA is essential to identify at-risk individuals. From 2018 to 2023, a total of 239,844 infants were screened. 13 positive screens were confirmed to have SMA. An additional case was determined to be a false positive. We are not aware of any false-negative cases. All patients were seen promptly, with diagnosis confirmed within 1 week of the initial clinical visit. Patients were treated with nusinersen or onasemnogene abeparvovec. Treated patients with two copies of SMN2 are meeting important developmental milestones inconsistent with the natural history of type 1 SMA. Patients with 3-4 copies of SMN2 follow normal developmental timelines. Newborn screening is an effective tool for the early identification and treatment of patients with SMA. Presymptomatic treatment dramatically shifts the natural history of SMA, with most patients meeting appropriate developmental milestones. Patients with two copies of SMN2 identified through newborn screening constitute a neurogenetic emergency. Due to the complexities of follow-up, a multidisciplinary team, including close communication with the newborn screening program, is required to facilitate timely diagnosis and treatment.
摘要:
脊髓性肌萎缩症(SMA)是一种常染色体隐性遗传疾病,其特征是脊髓前角的α运动神经元变性。在最严重的病例中,临床症状表现在生命的最初几周至几个月。导致近端随意肌进行性对称无力和萎缩。大约95%的SMA患者存在SMN1基因的纯合缺失。有多种可用的治疗方法可预防症状发展并减缓疾病进展,新生儿SMA筛查对于识别高危个体至关重要.从2018年到2023年,共筛查了239,844名婴儿。13个阳性筛选被证实具有SMA。另一个病例被确定为假阳性。我们不知道任何假阴性病例。所有患者都及时就诊,在初次临床就诊后1周内确诊。患者接受nusinersen或asemnogeneabeparvovec治疗。具有两个SMN2副本的治疗患者正在达到与1型SMA的自然史不一致的重要发展里程碑。具有3-4个SMN2拷贝的患者遵循正常的发育时间表。新生儿筛查是早期识别和治疗SMA患者的有效工具。症状前治疗极大地改变了SMA的自然史,大多数患者达到适当的发展里程碑。通过新生儿筛查确定的具有两个SMN2副本的患者构成神经遗传学紧急情况。由于后续行动的复杂性,多学科小组,包括与新生儿筛查项目的密切沟通,需要及时诊断和治疗。