Institute of Experimental Medicine, Christian-Albrechts University, Kiel, Germany.
Hum Mutat. 2011 Feb;32(2):144-51. doi: 10.1002/humu.21400.
The molecular genetic cause of over 3,000 monogenic disorders is currently unknown. This review discusses how novel genomic techniques like Next-Generation DNA Sequencing (NGS) and genotyping arrays open new avenues in the elucidation of genetic defects causing monogenic disorders. They will not only speed up disease gene identification but will enable us to systematically tackle previously intractable monogenic disorders. These are mainly disorders not amenable to classic linkage analysis, for example, due to insufficient family size. Most monogenic diseases are caused by exonic mutations or splice-site mutations changing the amino acid sequence of the affected gene. These mutations can be identified by sequencing of all exons in the human genome (exome sequencing) rendering whole genome sequencing unnecessary in most cases. Genotyping arrays containing 10⁵ -2×10⁶ single nucleotide polymorphisms (SNPs) and nonpolymorphic markers allow highly accurate mapping of genomic deletions and duplications not detectable by exome sequencing, which are the second most common cause of monogenic disorders. However, several hundred rare, previously unknown sequence variants affecting the amino acid sequence of the encoded protein are found in the exome of every human individual. Therefore, the main challenge will be the differentiation between the many rare benign variants detected by novel genomic techniques and disease causing mutations.
目前，超过 3000 种单基因疾病的分子遗传病因尚不清楚。本综述讨论了新型基因组技术，如下一代 DNA 测序（NGS）和基因分型阵列，如何为阐明导致单基因疾病的遗传缺陷开辟新途径。它们不仅将加快疾病基因的鉴定速度，还使我们能够系统地解决以前难以解决的单基因疾病。这些主要是由于家族规模不足等原因而不适于经典连锁分析的疾病。大多数单基因疾病是由改变受影响基因的氨基酸序列的外显子突变或剪接位点突变引起的。通过对人类基因组的所有外显子进行测序（外显子组测序）可以识别这些突变，在大多数情况下不需要进行全基因组测序。包含 10⁵-2×10⁶个单核苷酸多态性（SNP）和非多态性标记的基因分型阵列允许高度准确地映射基因组缺失和重复，这些缺失和重复通过外显子组测序是无法检测到的，它们是单基因疾病的第二大常见病因。然而，在每个人的外显子中都发现了数百种影响编码蛋白氨基酸序列的先前未知的稀有序列变异。因此，主要的挑战将是区分新型基因组技术检测到的许多罕见良性变异和致病突变。
