科學(xué)家發(fā)現(xiàn),，耳感覺毛細(xì)胞的一個基因表達(dá)突變是人類一種遺傳性耳聾的原因。這個稱為COMT2的基因為一種修改包括多巴胺在內(nèi)大腦化學(xué)信號的酶編碼,。COMT2和一個此前已知基因的相似性讓Bruce Beutler及其同事估計了COMT2基因的功能，他們最初把它當(dāng)成了一個造成小鼠行為缺陷的突變基因,。對來自有類似基因（Comt2）的小鼠細(xì)胞提取物的進(jìn)一步實驗證實了其功能,。
這組科學(xué)家確定了擁有突變的Comt2基因的小鼠在早年顯著耳聾。該病癥是隱性的,，即只有那些擁有兩個有缺陷的基因拷貝的小鼠才會耳聾,。這組科學(xué)家然后對192名聾人進(jìn)行了DNA測試，結(jié)果發(fā)現(xiàn)數(shù)個家族的COMT2基因發(fā)生了突變,。盡管目前對于這種突變還無法治療,，這個結(jié)果將幫助科學(xué)家理解神經(jīng)遞質(zhì)如何調(diào)控內(nèi)耳的毛細(xì)胞及其相關(guān)神經(jīng)的生存和功能。相關(guān)論文發(fā)表在美國《國家科學(xué)院院刊》（PNAS）上,。（生物谷Bioon.com）
生物谷推薦原始出處：
PNAS,，doi: 10.1073/pnas.0807219105，Xin Du,，Bruce Beutler
A catechol-O-methyltransferase that is essential for auditory function in mice and humans
Xin Du, Martin Schwander, Eva Marie Y. Moresco, Pia Viviani, Claudia Haller*, Michael S. Hildebrand§, Kwang Pak Lisa Tarantino, Amanda Roberts, Heather Richardson, George Koob, Hossein Najmabadi, Allen F. Ryan, Richard J. H. Smith, Ulrich Müller, and Bruce Beutler
We have identified a previously unannotated catechol-O-methyltranferase (COMT), here designated COMT2, through positional cloning of a chemically induced mutation responsible for a neurobehavioral phenotype. Mice homozygous for a missense mutation in Comt2 show vestibular impairment, profound sensorineuronal deafness, and progressive degeneration of the organ of Corti. Consistent with this phenotype, COMT2 is highly expressed in sensory hair cells of the inner ear. COMT2 enzymatic activity is significantly reduced by the missense mutation, suggesting that a defect in catecholamine catabolism underlies the auditory and vestibular phenotypes. Based on the studies in mice, we have screened DNA from human families and identified a nonsense mutation in the human ortholog of the murine Comt2 gene that causes nonsyndromic deafness. Defects in catecholamine modification by COMT have been previously implicated in the development of schizophrenia. Our studies identify a previously undescribed COMT gene and indicate an unexpected role for catecholamines in the function of auditory and vestibular sense organs.
