分子遺伝学総論・方法論：とくに精神疾患に焦点を当てて

Molecular genetic approaches for studying the etiology of psychiatric disorders

　精神疾患や高次脳機能障害の分子遺伝学的研究は，当初期待されたほどの成果を生み出していないように見える。その理由は，大部分の患者には影響力の小さい多くの遺伝子が関与する複雑疾患だからである。また，診断の問題という精神疾患に固有の困難もある。しかし，研究法の改良，解析技術の飛躍的進歩，ゲノム情報の充実など，複雑疾患でも本格的に解析できる環境が整いつつある。連鎖解析とそれに基づく関連解析や，候補遺伝子解析など従来から行われてきた解析の他に，ゲノムワイド関連解析，染色体異常症，動物モデルからの解析などが実際に成果を上げている。

　The majority of common psychiatric disorders still pose difficulties for geneticists because of their complex and non-Mendelian modes of inheritance. However, substantial progresses have been made in identifying genes associated with psychiatric disorders though genetic linkage and association studies, analyses of families with cosegregation of chromosomal translocations and psychiatric disorders, identifying contiguous gene microdeletion syndrome that increase risks for psychiatric problems and analyses of genetically engineered animal models. Furthermore, recent advance in the knowledge of the entire human genome and haplotype maps of the human genome will allow researchers to find genes and genetic variations that affect higher mental functions and to enable rational haplotype comparisons between studies. In addition, high throughput technologies such as arrays for genome-wide association studies, comparative genomic hybridization（CGH）, DNA methylation profiling will lead to major advances in understanding of the molecular basis of mental illness. These formidable tasks will be accomplished by continuing to harness the synergy between human and experimental genetic approaches.