Pou A
Servei de Neurologia, Hospital del Mar, Universitat Autónoma de Barcelona.
Neurologia. 1996 Dec;11 Suppl 5:43-57.
We propose a classification system for spinal muscular atrophies (SMA) based on the distribution of clinical signs, paresis and atrophy, as well as on the location of the responsible gene and the resulting enzyme deficiency, whenever these are known. This highly practical classification system encompasses three large SMA groups, as follows. A) Generalized forms, many of which are hereditary, are generally transmitted in a recessive autosomal manner. The course of disease is more severe when symptoms manifest early. Patients whose symptoms first occur after the first year of life often reach adolescence and even adulthood, confirming a highly apparent congruence of intermediate and pseudomyopathic juvenile forms. The same genetic defect, deletion in the 5q11-13.3 locus, that is responsible for acute infantile SMA has been demonstrated in both the aforementioned forms. B) Focal forms are restricted and often isolated cases; when they are hereditary, the genetic profile is highly heterogeneous. Though the disease will not necessarily evolve, it may progress to a generalized form. Focal forms may be symetric, assymetric, spinal-bulbar or multisegmental. The genetic abnormality has been identified for only some forms, such as chronic bulbar-spinal amyotrophy linked to the X-chromosome, at whose location, Xq11, the androgenic receptor is found. C) Amyotrophic lateral sclerosis (ALS) manifests clinically in a variety of ways and may be isolated, familial, juvenile or associated. Familial ALS is related to a gene defect in the 21q22.1 location that codifies for the superoxide dismutase enzyme. One juvenile form of ALS is related to a defect in the 2q33-35 chromosome. Any type of SMA can be related to degenerative neuronal disease of the central nervous system, especially juvenile ALS with generalized SMA, although such a link is at present merely an attractive hypothesis. Specific bibliographic references are given for each SMA form. Figures are provided to illustrate most of the SMA forms included in this classification system, the patients being at this time older adolescents and adults whose disease has been in evidence over many years.
我们基于临床体征、轻瘫和萎缩的分布情况，以及相关基因的位置和由此导致的酶缺乏情况（若已知），提出了一种脊髓性肌萎缩症（SMA）的分类系统。这个非常实用的分类系统包含以下三大类SMA。A）全身性类型，其中许多是遗传性的，通常以常染色体隐性方式遗传。症状出现得越早，病程越严重。症状在一岁以后首次出现的患者通常能活到青春期甚至成年，这证实了中间型和假肌病性青少年型之间有非常明显的一致性。在上述两种类型中都发现了与急性婴儿型SMA相关的相同基因缺陷，即5q11 - 13.3位点的缺失。B）局灶性类型较为局限，通常是孤立病例；若是遗传性的，其基因谱高度异质。虽然疾病不一定会进展，但可能会发展为全身性类型。局灶性类型可能是对称的、不对称的、脊髓延髓型或多节段型。仅对某些类型确定了基因异常，比如与X染色体相关的慢性延髓脊髓性肌萎缩症，在其位置Xq11上发现了雄激素受体。C）肌萎缩侧索硬化症（ALS）在临床上有多种表现形式，可能是散发性、家族性、青少年型或伴发其他病症。家族性ALS与位于21q22.1位置的一个编码超氧化物歧化酶的基因缺陷有关。一种青少年型ALS与2q33 - 35染色体上的缺陷有关。任何类型的SMA都可能与中枢神经系统的退行性神经元疾病有关，尤其是青少年型ALS合并全身性SMA，不过目前这种联系仅仅是一个有吸引力的假说。每种SMA类型都给出了具体的文献参考。提供了图表来说明这个分类系统中包含的大多数SMA类型，患者为年龄较大的青少年和成年人，他们的疾病已经显现多年。
