Ultrastructural and immunofluorescence analysis of anterior lens capsules in autosomal recessive Alport syndrome

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 alpha 2, alpha 3, and alpha 4 chains of type 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 alpha 2 chain and decreased reactivity against the alpha 3 and alpha 4 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 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.