ABSTRACT

Background: To first report and study the ultrastructural and immunofluorescence abnormalities of the lens anterior capsules in a patient with autosomal recessive Alport syndrome.

Methods: Two anterior lens capsules were collected in femtosecond laser-assisted cataract surgeries from a 29-year-old male patient with bilateral lenticonus caused by autosomal recessive Alport syndrome. The left capsule was examined by transmission electron microscopy and the right capsule was serial sectioned and stained with antibodies against the α2, α3, and α4 chains of type Ⅳ collagen. Anterior lens capsules of another two uncomplicated age-related cataract patients were collected and treated in the same way as the control.

Results: The novel findings are that the mitochondria in lens epithelial cells in autosomal recessive Alport syndrome patients increased, twisted, and exhibited high electron density. Characteristic ultrastructure changes of capsule thinning, vertical dehiscence, and irregular-shaped lens epithelial cells were also observed in the left anterior lens capsule. Normal reactivity against the α2 chain and decreased reactivity against the α3 and α4 chains were observed in the right anterior lens capsule.

Conclusions: The homozygous c.4599 T > G mutation of COL4A4 not only affects the formation of type Ⅳ collagen networks in the extracellular matrix, but also affects the morphology and survival of the lens epithelial cells in the patient with autosomal recessive Alport syndrome. This study is the first report of the ultrastructural and immunofluorescence changes of anterior lens capsules in autosomal recessive Alport syndrome.

摘要

背景：首先报告和研究一例常染色体隐性遗传Alport综合征患者晶状体前囊的超微结构和免疫荧光异常。

方法：在飞秒激光辅助白内障手术中收集了两个前晶状体囊，该患者来自一名 29 岁的常染色体隐性遗传 Alport 综合征引起双侧晶状体的男性患者。透射电镜观察左囊，右囊连续切片，用抗Ⅳ型胶原α2、α3和α4链的抗体染色。收集另外两名无并发症的年龄相关性白内障患者的前晶状体囊，并以与对照组相同的方式进行治疗。

结果：新发现是常染色体隐性遗传Alport综合征患者晶状体上皮细胞线粒体增加、扭曲并表现出高电子密度。在左前晶状体囊中也观察到囊变薄、垂直开裂和不规则形状的晶状体上皮细胞的特征性超微结构变化。在右前晶状体囊中观察到对 α2 链的正常反应性和对 α3 和 α4 链的反应性降低。

结论：COL4A4纯合子c.4599 T>G突变不仅影响细胞外基质Ⅳ型胶原网络的形成，而且影响常染色体隐性遗传Alport综合征患者晶状体上皮细胞的形态和存活。本研究首次报道常染色体隐性Alport综合征患者晶状体前囊的超微结构和免疫荧光变化。