Kurtz B S, Lehman J, Garlick P, Amberg J, Mishra P K, Dailey J W, Weber R, Jobe P C
Biology Department, Bradley University, Peoria, IL 61625, USA.
J Neurogenet. 2001;15(3-4):233-44. doi: 10.3109/01677060109167379.
In order to understand the level of complexity of the epileptic phenotype in the two strains of Genetically Epilepsy-Prone Rats (GEPRs), we determined two important measures of genetic complexity, penetrance and expressivity. Penetrance is the percentage of animals of a specific genotype who express the phenotype associated with that underlying genotype. Expressivity refers to the degree that a particular genotype is expressed as a phenotype within an individual. Incomplete penetrance and variable expressivity are caused by genetic and environmental variation. In this paper we have studied the epileptic phenotype for 20,373 rats. Animals were tested on three occasions for audiogenic seizure and given an audiogenic response score (on a scale of 0-9, 0 being no seizure and 9 being the most severe). The GEPR-3 and GEPR-9 animals both show incomplete penetrance and variable expressivity of the underlying genetic predisposition. The GEPR-9 strain has more animals that have variable levels of seizure predisposition (as measured by a scoring system that denotes the severity of generalized tonic/clonic seizures) and a greater percentage of animals that exhibit no susceptibility to such seizures induced by sound. Both strains have a number of animals that are not susceptible to sound-induced GTCSs and that exhibit some variability in seizure severity. The GEPR-9 males show greater differences in expressivity and penetrance compared to GEPR-9 females. The GEPR-3 animals also show sex-associated variable penetrance and expressivity of the epileptic phenotype, although the differences are much smaller. These findings are the first step toward the mapping of the underlying quantitative trait loci (QTL) for seizure in these animals.
为了了解两种遗传性癫痫易感性大鼠（GEPRs）品系中癫痫表型的复杂程度，我们确定了两个重要的遗传复杂性指标：外显率和表现度。外显率是指具有特定基因型的动物中表现出与该潜在基因型相关表型的百分比。表现度是指特定基因型在个体中表现为表型的程度。不完全外显率和可变表现度是由遗传和环境变异引起的。在本文中，我们研究了20373只大鼠的癫痫表型。对动物进行了三次听源性惊厥测试，并给出了听源性反应评分（范围为0 - 9，0表示无惊厥，9表示最严重）。GEPR - 3和GEPR - 9动物均表现出潜在遗传易感性的不完全外显率和可变表现度。GEPR - 9品系中有更多动物具有不同程度的惊厥易感性（通过表示全身性强直/阵挛性惊厥严重程度的评分系统来衡量），并且有更大比例的动物对声音诱发的此类惊厥不敏感。两个品系都有一些动物对声音诱发的全身性强直/阵挛性惊厥不敏感，并且在惊厥严重程度上表现出一定的变异性。与GEPR - 9雌性动物相比，GEPR - 9雄性动物在表现度和外显率上表现出更大的差异。GEPR - 3动物也表现出癫痫表型的性别相关可变外显率和表现度，尽管差异要小得多。这些发现是在这些动物中绘制癫痫潜在数量性状基因座（QTL）的第一步。
