家族性牙釉質發育不全症之突變分析

Mutational Analyses of Amelogenesis Imperfecta Kindreds

林錫奎(Hsi-Kuei Lin) ； 陳玫秀(May-Show Chen) ； 胡淨娟(Jan C-C Hu)

《中華牙醫學雜誌（中文版）》 26卷1期 (2007/03) Pp. 1-8

https://doi.org/10.7106/CJD.200703.0001

摘要

各種不同的牙釉質形成的遺傳性缺陷，全都被歸類為牙釉質發育不全症(Amelogenesis Imperfecta, AI)。根據嚴格定義，AI指的是那些只有釉質缺陷，但齒列外沒有症狀（無症候群）的病例。AI病患的臨床表現型包括：牙釉質層的厚度、硬度、粗糙感和顏色等的病理變化。這些變化有些小到只有局部凹陷，但有些則會造成嚴重的牙釉質缺損(agenesis)。而牙釉質發育不全症的遺傳方式則有體染色體顯性遺傳、體染色體隱性遺傳或性聯遺傳等。雖然AI的病因牽涉到多個基因，但是家族性牙釉質缺陷可能是任一特定親屬的單一個基因缺陷所造成。目前已經證實的可能基因有四個：amelogenin(AMELX)、enamelin(ENAM)、enamelysin(MMP20)和kallikrein 4(KLK4)，另外還有兩個被認為可能的基因：ameloblastin(AMBN)和tuftelin(TUFT1)，也許還有更多的可能基因有待發掘。目前使用以上所列之可能基因所作的突變分析，鑑識造成突變的原因，成功的機率不到50%。雖然如此，突變分析還是有助於建立基因型和表現型兩者的關聯性，以及基因型和治療結果之間的關聯性。本報告的目的，是要提供一份關於家族性AI的突變分析之簡潔摘要，讓牙科醫師能對一些已被確定的家族性的AI基因突變、臨床表現類型和對治療的反應（例如：牙釉質黏著）等基礎知識之增長有所貢獻。

關鍵字

牙釉質發育不全症

並列摘要

The spectrum of inherited defects of dental enamel formation are grouped together under the designation of amelogenesis imperfecta (AI). According to a strict definition, AI includes only those cases in which the enamel defects occur in the absence of symptoms outside of the dentition (i.e., they are non-syndromic). Clinical phenotypes in patients with AI include pathological variations in the thickness, hardness, roughness, and color of the enamel layer, and can be as minor as localized pitting or as extreme as enamel agenesis. The pattern of inheritance of AI can be autosomal dominant, autosomal recessive, or X-linked. While multiple genes are involved in the etiology of AI, defects in a single gene are likely to be the cause of the enamel defects in any given kindred. Currently, there are 4 proven candidate genes for AI: amelogenin (AMELX), enamelin (ENAM), enamelysin (MMP20) and kallikrein 4 (KLK4) and 2 proposed candidate genes: ameloblastin (AMBN), and tuftelin (TUFT1). More candidate genes await discovery, and mutational analyses using the listed candidate genes have less than a 50% chance of identifying the causative mutation. Despite this, mutational analyses are helping to establish correlations between genotypes and phenotypes and between genotypes and treatment outcomes, which may lead to the provision of improved treatment. The purpose of this report is to provide a concise summary of how mutational analyses are performed in AI kindreds, so that more dental scientists can contribute to the growing knowledge-base of related people with defined AI-causing mutations, clinical phenotypes, and responses to treatment, such as enamel bonding.

並列關鍵字

amelogenesis imperfecta