Ashizawa T, Hejtmancik J F, Liu J, Perryman M B, Epstein H F, Koch D D
Department of Neurology, Baylor College of Medicine, Houston, Tex 77030.
Am J Med Genet. 1992 Jan 1;42(1):55-60. doi: 10.1002/ajmg.1320420113.
To determine diagnostic value of lens opacities in myotonic dystrophy (DM), we examined 98 at-risk members of 9 DM kindreds. Haplotype analysis of restriction fragment length polymorphisms (RFLPs) using ApoC2, CKMM, and pEFD4.2 supported the diagnosis of DM in 33 and excluded the diagnosis in 51 members. The sensitivities of bilateral iridescent lens opacities, posterior cortical lens opacities, orbicularis oculi weakness, low intraocular pressure, ptosis, and ocular myotonia were 46.7, 50.0, 60.6, 59.3, 51.5, and 3.0%, while their specificities were 100.0, 100.0, 98.0, 94.1, 96.1, and 100.0%, respectively. A peripheral pigmentary degeneration and central macular lesions of retina were not found on indirect fundoscopy. In 86.2% of DM patients, bilateral iridescent lens opacities, posterior cortical lens opacities, or both were present. Unilateral iridescent lens opacities occurred in only 3 of our DM patients, and 2 of non-DM relatives showed a few unilateral iridescent particles. Posterior cortical lens opacities in DM patients always affected both eyes in this series. We conclude that 1) bilateral iridescent lens opacities and posterior cortical lens opacities are highly specific for DM and useful for establishing clinical diagnosis of DM, 2) unilateral iridescent lens opacities are infrequent in DM and are seen in some non-DM members, and 3) ocular myotonia and clinical retinopathies are rare in DM.
为了确定晶状体混浊在强直性肌营养不良（DM）中的诊断价值，我们检查了9个DM家系的98名高危成员。使用载脂蛋白C2、肌酸激酶MM和pEFD4.2对限制性片段长度多态性（RFLP）进行单倍型分析，支持33名成员的DM诊断，并排除了51名成员的诊断。双侧彩虹样晶状体混浊、后皮质晶状体混浊、眼轮匝肌无力、低眼压、上睑下垂和眼肌强直的敏感性分别为46.7%、50.0%、60.6%、59.3%、51.5%和3.0%，而它们的特异性分别为100.0%、100.0%、98.0%、94.1%、96.1%和100.0%。间接检眼镜检查未发现视网膜周边色素变性和黄斑中心病变。在86.2%的DM患者中，存在双侧彩虹样晶状体混浊、后皮质晶状体混浊或两者皆有。我们的DM患者中只有3例出现单侧彩虹样晶状体混浊，2例非DM亲属有少量单侧彩虹样颗粒。在本系列中，DM患者的后皮质晶状体混浊总是累及双眼。我们得出结论：1）双侧彩虹样晶状体混浊和后皮质晶状体混浊对DM具有高度特异性，有助于建立DM的临床诊断；2）单侧彩虹样晶状体混浊在DM中不常见，在一些非DM成员中也可见到；3）眼肌强直和临床视网膜病变在DM中很少见。
