Two novel SOD1 mutations in patients with familial amyotrophic lateral sclerosis.
Two novel SOD1 mutations in patients with familial amyotrophic lateral sclerosis.
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DOI：
10.1093/hmg/4.6.1113
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发表时间：
1995-06
影响因子：
3.5
通讯作者：
H. Deng;J. Tainer;H. Mitsumoto;H. Mitsumoto;Akio Ohnishi;Xiaoxuan He;W. Hung;Yaliang Zhao;T. Juneja;A. Hentati;Teepu Siddique
中科院分区：
文献类型：
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作者：
H. Deng;J. Tainer;H. Mitsumoto;H. Mitsumoto;Akio Ohnishi;Xiaoxuan He;W. Hung;Yaliang Zhao;T. Juneja;A. Hentati;Teepu Siddique
肌萎缩侧索硬化症（ALS）是一种进行性麻痹性疾病，由于大的运动神经元的脑和脊髓的变性。疾病的持续时间通常在临床症状出现后不到5年。大约5 - 10%的ALS病例是家族性的（FALS）。在临床上与散发性ALS难以区分的FALS是一种常染色体显性遗传性状，具有年龄依赖性遗传率（1）。遗传连锁研究在染色体21q22上建立了一个FALS基因座。1，与胞质Cu/Zn超氧化物歧化酶（SOD 1）的基因接近（2）。随后，在与21号染色体基因座连锁的FALS家族中鉴定了SOD1突变（3，4）。对野生型SOD结构中突变位点的研究预测，突变会导致结构不稳定，从而导致SOD蛋白的稳定性和活性降低（4）。首先在红细胞中证明的酶活性降低（4），随后在具有SOD1突变的FALS患者的脑和淋巴母细胞中得到证实（5 - 7）。G93A突变过表达的转基因小鼠模型与人ALS表型相似（8，9）。已经在FALS中鉴定了涉及18种不同密码子的总共23种不同突变（3 - 5，10 - 13，以及在会议上的交流：SOD，自由基和ALS，Laker海崖，Illinois. 1994年9月）。我们现在报告两个额外的突变SOD1基因在我们的ALS患者中确定。用于外显子2和4的PCR扩增的引物序列已在（3）中作为组B报道，并且用于外显子1和5的引物序列已在（4）中描述。用于外显子3分析的引物是：（i）5'TGGGAACTTTAATTCATAATT 3 '和（ii）5'AGTATACCATATGAACTCCA 3'。在0.5 X突变检测增强（MDE; JT Baker）、5%甘油凝胶中用单链构象多态性（SSCP）分析PCR产物。对有SSCP改变的DNA样品进行PCR扩增。将PCR产物在6%丙烯酰胺凝胶中纯化，并使用两种扩增引物独立地用PCR循环测序进行测序。我们已经确定了15个不同的突变，在37个家庭的共222个家庭筛选。这些突变中有两个以前没有报道过（表1）。此外，在一个明显散发的患者中发现了密码子113（ATT到ACT）的突变。这里描述的突变发生在外显子1的密码子14处，其将密码子从GTG改变为ATG，并且将氨基酸从缬氨酸改变为甲硫氨酸（图la）和外显子4的密码子84处，其将密码子从TTG改变为GTG，并且氨基酸亮氨酸改变为缬氨酸。在鉴定的15个突变中，密码子4处的GCC至GTC突变（其将氨基酸从丙氨酸改变为缬氨酸（A4V））是最常见的。除了先前报道的8个具有这种突变的家庭外，我们还发现了另外10个具有相同突变的FALS家庭。这种突变（A4V）占我们已确定SOD1突变的FALS家族的近一半（37个中的18个）。在36个FALS家族中报告了另外14个A4V突变（7）。第二个最常见的突变是在密码子113处，ATT到ACT，其将氨基酸异亮氨酸改变为苏氨酸。我们已经确定了这种突变在三个FALS家庭和一个明显的散发病例。在另外三个明显散发的病例中也报告了I113 T突变（11，14）。这种突变可能伪装成一个新的突变，在散发性ALS由于其较低的突变率，特别是当家族史是不完整的。我们还发现了两个A4T突变的家族，一个额外的家族，每个家族分别具有E100G和L144F突变。那个...
Amyotrophic lateral sclerosis (ALS) is a progressive paralytic disorder due to the degeneration of large motor neurons of the brain and spinal cord. The duration of the disease is usually less than 5 years after onset of clinical symptoms. About 5-10% of the ALS cases are familial (FALS). FALS, clinically indistinguishable from sporadic ALS, is inherited as an autosomal dominant trait with age-dependent penetrance (1). Genetic linkage studies established a locus for FALS on chromosome 21q22. 1, in proximity to the gene for cytosolic Cu/Zn superoxide dismutase (SOD1)(2). Subsequently, mutations in SOD1 were identified in FALS families linked to the chromosome 21 locus (3, 4). Studies of mutant sites in the wild-type SOD structure predict the mutations to cause structural instability leading to a less stable and less active SOD protein (4). Decreased enzyme activity first demonstrated in the red cells (4) was later confirmed in brain and lymphoblastoid cells of the FALS patients with SOD1 mutations (5-7). A transgenic mouse model, with over-expression of the G93A mutation, resembles the human ALS phenotype (8, 9). A total of 23 different mutations involving 18 distinct codons have been identified in FALS (3-5, 10-13, and communications at the conference: SOD, Free Radicals and ALS, Laker Bluff, Illinois. September 1994). We now report two additional mutations in SOD1 gene identified in our FALS patients. Primer sequences for PCR amplification of exon 2 and 4 have been reported in (3) as set b, and those for exons 1 and 5 have been described in (4). The primers used in the analysis of exon 3 are:(i) 5'TGGGAACTTTAATTCATAATT 3'and (ii) 5'AGTATACCATATGAACTCCA 3'. The PCR products were analyzed with single-stranded conformation polymorphism (SSCP) in 0.5 X mutation detection enhancement (MDE; JT Baker), 5% glycerol gels. The DNA samples with SSCP changes were PCR amplified. The PCR products were purified in a 6% acrylamide gel and sequenced with PCR cycle sequencing independently using two amplification primers. We have identified 15 different mutations in 37 FALS families out of a total of 222 families screened. Two of these mutations have not been previously reported (Table 1). In addition, a mutation at codon 113 (ATT to ACT) was found in an apparently sporadic patient. The mutations described here occur at codon 14 of exon 1 which changes the codon from GTG to ATG and amino acid from valine to methionine (Fig. la) and at codon 84 of exon 4 which changes the codon from TTG to GTG, and the amino acid leucine to valine (Fig. lb).Among the 15 mutations identified, the GCC to GTC mutation at codon 4, which changes amino acid from alanine to valine (A4V) is the most frequent. In addition to the previously reported eight families with this mutation (4), we have found another 10 FALS families that have the same mutation. This mutation (A4V) accounts for almost half (18 of 37) of our FALS families in which SOD1 mutations have been identified. An additional 14 A4V mutations have been reported among 36 FALS families (7). The second most frequent mutation is at codon 113, ATT to ACT, which changes amino acid isoleucine to threonine. We have identified this mutation in three FALS families and in one apparently sporadic case. I 113 T mutation has also been reported in three other apparently sporadic cases (11, 14). This mutation probably masquerades as a new mutation in sporadic ALS due to its lower penetrance, especially when the family history is incomplete. We have also identified two families with the A4T mutation, an additional family, each with the E100G and L144F mutations respectively. The …