Kärrman C, Bäckman B, Holmgren G, Forsman K
Department of Clinical Genetics, University Hospital, Umeå, Sweden.
Arch Oral Biol. 1996 Aug-Sep;41(8-9):893-900. doi: 10.1016/s0003-9969(96)00010-6.
Amelogenesis imperfecta (AI) is a group of hereditary enamel defects, characterized by large clinical diversity. On the basis of differences in clinical manifestation and inheritance pattern, 14 different subtypes have been recognized. A locus for autosomal dominant AI (ADAI) of local hypoplastic type was recently mapped to the region between D4S392 and D4S395 on the long arm of chromosome 4. To test whether the chromosome 4 locus is responsible for other forms of AI as well, a linkage study was carried out with 17 families representing at least five clinical forms of ADAI. Admixture tests for heterogeneity performed with the marker D4S2456 gave statistical support for genetic heterogeneity of ADAI with the odds 78:1. Linkage to the ADAI locus on chromosome 4q (AIH2) could only be demonstrated with families expressing the local hypoplastic type, and there was no support for heterogeneity within that group of families. Furthermore, linkage could be excluded for five families with other clinical forms of ADAI. The data therefore demonstrated that ADAI is genetically heterogeneous, and that at least two loci for it exist.
牙釉质发育不全（AI）是一组遗传性牙釉质缺陷，其临床差异很大。根据临床表现和遗传模式的差异，已识别出14种不同的亚型。常染色体显性局部发育不全型AI（ADAI）的一个基因座最近被定位到4号染色体长臂上D4S392和D4S395之间的区域。为了检验4号染色体基因座是否也与其他形式的AI有关，对代表至少五种ADAI临床形式的17个家族进行了连锁研究。用标记D4S2456进行的异质性混合检验为ADAI的遗传异质性提供了统计学支持，优势比为78:1。只有那些表现为局部发育不全型的家族才能证明与4号染色体上的ADAI基因座（AIH2）存在连锁关系，而且在该组家族中没有证据支持异质性。此外，对于另外五个具有其他ADAI临床形式的家族，可以排除连锁关系。因此，数据表明ADAI在遗传上是异质的，并且至少存在两个与之相关的基因座。
