Canine eyelid granular cell tumor: a report of eight cases

To describe a previously unreported neoplasm of the medial canthus and eyelid in dogs. Clinical and pathologic features of granular cell tumors in the dog were reviewed. Granular cell tumors, arising from the medial canthal eyelid of eight dogs, were identified from the archives of the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW). The affected dogs ranged in age from 5 to 12 years (mean of 9.25 years). Follow‐up information was available for seven of the eight cases. The clinical presentation included swollen hyperemic lids (4/8), ulcerated skin overlying the mass (2/8), and red conjunctiva (7/8). All eight of the cases had firm masses extending from the palpebral conjunctiva to the eyelid margin at the medial canthus. Histologically, the tissue was composed of a highly collagenous neoplastic growth. The neoplastic cells were oval to strap‐like cells with an oval bland appearing nucleus and abundant amounts of granular cytoplasm with very distinct cell boundaries. These granular cells were embedded in a dense collagen matrix. A PAS stain faintly highlighted the granular appearance of the neoplastic cells, which is a defining characteristic of this tumor. There was no recurrence in the seven cases available for follow‐up. Canine granular cell tumors of the medial canthus present clinically and histologically as a benign neoplasm. Granular cell tumors have a characteristic histological appearance. Granular cell tumors should be on the differential list for nodules of the medial canthus in dogs.     

鹅豁眼性状H基因座候选基因FREM1的验证分析

【目的】鹅豁眼性状呈隐性伴性遗传,其遗传基础有待揭示。基因FRAS-related extracellular matrix 1(FREM1)编码区的一些隐性突变导致了人类及模型小鼠上眼睑部分或完全缺失。本试验以鹅豁眼性状资源群为主要材料,通过对鹅基因FREM1的克隆、表达及基因多态性分析,验证FREM1是影响鹅上眼睑性状候选基因的假设,为深入研究眼睑性状的分子遗传机制奠定基础。【方法】采集鹅豁眼性状F2资源群中成年纯种豁眼鹅母鹅(3只)、四川白鹅(6只,雌雄各半)、♂豁眼×♀四川白鹅F1代公鹅(3只)的眼睑和肾组织,提取其总RNA,以鹅FREM1(XM_013193557)全长转录序列为参考设计引物,利用反转录RT-PCR克隆鹅FREM1基因,对其进行生物信息学分析,进而,采用实时荧光定量PCR法研究鹅眼睑和肾组织FREM1基因的表达特性。采集成年纯种豁眼鹅公鹅、四川白鹅公鹅和♂豁眼×♀四川白鹅正反交F1代公鹅各30只的血液,提取全血DNA,以鹅FREM1(Anser cygnoides domesticus breed Zhedong scaffold203_32,NCBI)序列设计引物,利用直接测序法检测FREM1基因变异位点在不同鹅群体中的分布情况。【结果】(1)经测序和拼接,获得鹅FREM1基因c DNA序列7 305bp,该序列包含一个完整的CDS(Coding Sequences)区,编码2 184个氨基酸。与四川白鹅和浙东白鹅相比,在豁眼鹅FREM1基因CDS序列上发现第4 515bp:TC是错义突变,导致第1 505aa:ValAla变化,位于FREM1蛋白的CSPG重复结构域中第10个CSPG上。利用在线工具SIFT预测该氨基酸替换对蛋白功能的影响较小。通过I-MutantΔΔG和MUPro程序分析,p.1505VA位点氨基酸替换大幅度降低了FREM1蛋白的稳定性。(2)FREM1基因在四川白鹅公、母鹅的眼睑和肾脏2个组织中均有表达,但肾脏表达水平远远高于眼睑,更为重要的是,公鹅FREM1基因的组织表达水平正好接近母鹅的2倍。ZHW(正常眼睑)和ZhW(上眼睑部分缺失)基因型鹅FREM1基因相对表达量无差异(P0.05),虽然ZHZh(正常眼睑)基因型鹅的FREM1基因相对表达量是ZHW和ZhW基因型鹅的2倍多,但这可能是性别不同导致的差异。(3)豁眼鹅群体中基因型HH、Hh和hh的频率分别是0、0和1.0,等位基因H和h的频率分别是0和1.0,杂合度为0;四川白鹅群体中基因型HH、Hh和hh的频率分别是1.0、0和0,等位基因H和h的频率分别是1.0和0,杂合度为0;F1代群体中基因型HH、Hh和hh的频率分别是0、1.0和0,等位基因H和h的频率分别是0.5和0.5,杂合度为1.0。【结论】基因FREM1是决定鹅上眼睑性状的H基因座,该基因编码区1个纯合型错义突变导致了FREM1蛋白第10个CSPG结构域的变化,从而影响了FREM1蛋白的稳定性,基因FREM1的c.4514TC突变可作为鹅豁眼性状重要的分子标记。