Spinal muscular atrophy genotyping by gene dosage using multiple ligation-dependent probe amplification
Spinal muscular atrophy genotyping by gene dosage using multiple ligation-dependent probe amplification
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DOI：
10.1007/s10048-006-0051-3
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发表时间：
2006-11-01
期刊：
影响因子：
2.2
通讯作者：
Dallapiccola, Bruno
中科院分区：
文献类型：
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作者：
Scarciolla, Oronzo;Stuppia, Liborio;Dallapiccola, Bruno
脊髓性肌萎缩症（SMA）是一种常染色体隐性疾病，其特征是脊髓前角细胞变性，导致对称性近端肌无力。根据症状的严重程度和发病年龄，SMA分为三种临床类型：SMA I、SMA II和SMA III。大约95%的SMA病例是由存活运动神经元1 （SMN1）基因（5q13）的纯合缺失或其向SMN2的转化引起的。这种疾病的分子诊断通常通过聚合酶链反应-限制性片段长度多态性方法进行，该方法能够证明两个SMN1拷贝的缺失。然而，这种方法无法识别杂合子健康携带者，这在一般人群中显示出非常高的频率（1:50）。我们使用多重结扎依赖探针扩增（MLPA）方法对19名SMA患者和57名有成为健康携带者风险的个体进行了SMA的分子诊断。该分析在所有调查的病例中检测到纯合子SMN1的缺失，并允许根据SMA关键区域内不同基因特异性峰所显示的大小来区分SMN1缺失和向SMN2转化。此外，MLPA分析证实了57名受影响患者亲属中33人缺乏杂合子SMN1的情况，证明了该方法在识别健康携带者方面的有效性。因此，MLPA技术代表了一种简单、低成本和高通量的分子诊断系统，无论是在受影响的患者还是在健康的携带者中。
Spinal muscular atrophy (SMA) is an autosomal recessive disease characterized by degeneration of the anterior horn cells of the spinal cord, causing symmetric proximal muscle weakness. SMA is classified in three clinical types, SMA I, SMA II, and SMA III, based on the severity of the symptoms and the age of onset. About 95% of SMA cases are caused by homozygous deletion of the survival motor neuron 1 (SMN1) gene (5q13), or its conversion to SMN2. The molecular diagnosis of this disease is usually carried out by a polymerase chain reaction-restriction fragment length polymorphism approach able to evidence the absence of both SMN1 copies. However, this approach is not able to identify heterozygous healthy carriers, which show a very high frequency in general population (1:50). We used the multiple ligation-dependent probe amplification (MLPA) approach for the molecular diagnosis of SMA in 19 affected patient and in 57 individuals at risk to become healthy carriers. This analysis detected the absence of the homozygous SMN1 in all the investigated cases, and allowed to discriminate between SMN1 deletion and conversion to SMN2 on the basis of the size showed by the peaks specific for the different genes mapped within the SMA critical region. Moreover, MLPA analysis evidenced a condition of the absence of the heterozygous SMN1 in 33 out of the 57 relatives of the affected patients, demonstrating the usefulness of this approach in the identification of healthy carriers. Thus, the MLPA technique represents an easy, low cost, and high throughput system in the molecular diagnosis of SMA, both in affected patients and in healthy carriers.