Zerres K, Rudnik-Schöneborn S
Institute for Human Genetics, University of Bonn, Germany.
Arch Neurol. 1995 May;52(5):518-23. doi: 10.1001/archneur.1995.00540290108025.
To describe the natural history in all types of proximal spinal muscular atrophy (SMA) and to propose a modified classification scheme that takes the long-term course of SMA into account.
Patients with proximal SMA were studied prospectively and retrospectively in a genetic study that was based on clinical and family data.
Four hundred forty-five patients with SMA were ascertained since 1985 through various departments of neurology and neuropediatrics, institutes of human genetics, and the German muscular dystrophy association (Deutsche Gesellschaft für Muskelkranke, Freiburg, Germany).
The study group was subdivided into patients with four types of SMA (ie, SMA types I, II, III, and IV) on the basis of achieved motor development and age at onset. Survival probabilities at 2, 4, 10, and 20 years of age were 32%, 18%, 8%, and 0%, respectively, in patients with SMA type I (those who were never able to sit) and 100%, 100%, 98%, and 77%, respectively, in patients with SMA type II (those who were able to sit but were unable to walk). Nineteen of 104 patients with SMA type II lost the ability to sit; this inability to sit was not of prognostic relevance. Patients with SMA type III (those who were able to walk [age at onset, younger than 30 years]) were subdivided into those with an age at onset before (SMA type IIIa) and after (SMA type IIIb) 3 years. The probabilities of being ambulatory at 10, 20, and 40 years after onset were 73%, 44%, and 34%, respectively, in patients with SMA type IIIa, and they were 97%, 89%, and 67%, respectively, in patients with SMA type IIIb.
The definition of long-term characteristics of SMA is helpful in providing medical care to families with members who have SMA and also in providing important information for future genotype-phenotype studies and therapeutic trials of patients with SMA. Our data indicate that the widely used classification schemes did not consider the broad spectrum of SMA so a practical modification was suggested.
描述各类近端脊髓性肌萎缩症（SMA）的自然病程，并提出一种考虑到SMA长期病程的改良分类方案。
在一项基于临床和家族数据的基因研究中，对近端SMA患者进行前瞻性和回顾性研究。
自1985年以来，通过神经科和神经儿科各科室、人类遗传学研究所及德国肌肉萎缩症协会（德国弗赖堡肌肉疾病协会）确诊了445例SMA患者。
根据运动发育情况和发病年龄，研究组被分为四种类型的SMA患者（即SMA Ⅰ型、Ⅱ型、Ⅲ型和Ⅳ型）。SMA Ⅰ型患者（从未能够坐立者）在2岁、4岁、10岁和20岁时的生存概率分别为32%、18%、8%和0%，而SMA Ⅱ型患者（能够坐立但不能行走者）的相应概率分别为100%、100%、98%和77%。104例SMA Ⅱ型患者中有19例失去了坐立能力；这种无法坐立与预后无关。SMA Ⅲ型患者（能够行走[发病年龄小于30岁]）又被细分为发病年龄在3岁之前（SMA Ⅲa型）和之后（SMA Ⅲb型）的患者。SMA Ⅲa型患者发病后10年、20年和40年仍能行走的概率分别为73%、44%和34%，SMA Ⅲb型患者的相应概率分别为97%、89%和67%。
SMA长期特征的定义有助于为有SMA患者的家庭提供医疗护理，也为未来SMA患者的基因型-表型研究和治疗试验提供重要信息。我们的数据表明，广泛使用的分类方案未考虑到SMA的广泛谱系，因此建议进行实际改良。
