Alasti F, Van Camp G
Department of Medical Genetics, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
J Med Genet. 2009 Jun;46(6):361-9. doi: 10.1136/jmg.2008.062158. Epub 2009 Mar 16.
Microtia is a congenital anomaly, characterised by a small, abnormally shaped auricle (pinna). It is usually accompanied by a narrow, blocked or absent ear canal. Microtia can occur as the only clinical abnormality or as part of a syndrome. The estimated prevalence of microtia is 0.8-4.2 per 10 000 births, and it is more common in men. Microtia can have a genetic or environmental predisposition. Mendelian hereditary forms of microtia with an autosomal dominant or recessive mode of inheritance, and some forms due to chromosomal aberrations have been reported. Several responsible genes have been identified, most of them being homeobox genes. Mouse models have been very useful to study these genes, providing valuable information on the development of the auditory system. In this article, we review the epidemiological characteristics of microtia and the environmental causes involved. In addition, we discuss the development of the auditory system, specifically the relevant aspects of external and middle ear development. The focus of this review is to discuss the genetic aspects of microtia and associated syndromes. The clinical aspects of various disorders involving microtia are also discussed in relation to the genes that are causing them.
小耳畸形是一种先天性异常，其特征为耳廓（耳郭）小且形状异常。它通常伴有耳道狭窄、堵塞或缺失。小耳畸形可作为唯一的临床异常出现，也可作为综合征的一部分。小耳畸形的估计患病率为每10000例出生中有0.8 - 4.2例，且在男性中更为常见。小耳畸形可能有遗传或环境易感性。已报道了具有常染色体显性或隐性遗传模式的孟德尔遗传性小耳畸形形式，以及一些由染色体畸变引起的形式。已鉴定出多个相关基因，其中大多数是同源盒基因。小鼠模型对研究这些基因非常有用，为听觉系统的发育提供了有价值的信息。在本文中，我们综述了小耳畸形的流行病学特征以及相关的环境病因。此外，我们讨论了听觉系统的发育，特别是外耳和中耳发育的相关方面。本综述的重点是讨论小耳畸形及相关综合征的遗传方面。还结合导致各种涉及小耳畸形疾病的基因讨论了其临床方面。
