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PAX6 mutations identified in 4 of 35 families with microcornea
Panfeng Wang1, Wenmin Sun, Shiqiang Li
1State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
Purpose:
Mutations in paired box gene 6 (PAX6) are the major cause of aniridia that may associate with several other developmental anomalies of the eye, including microcornea in rare cases. However, systemic evaluation of PAX6 in patients with microcornea as the major sign has not been reported. This study aims to detect PAX6 mutations in patients with microcornea.
Methods:
Genomic DNA of probands was prepared from 35 families with microcornea. The coding regions of PAX6 were screened by Sanger sequencing and novel variations were further evaluated in 192 normal individuals. Bioinformatics analysis was used to evaluate the structural consequences related to the pathology of the mutations.
Results:
The average corneal horizontal diameter of the 35 probands is 8.03 ± 1.27 mm (the median value is 8 mm). Among them, eight patients presented with normal iris, one had aniridia, and different severities of iris hypoplasia were detected in the rest. In four probands, three heterozygous variations in PAX6 were identified: a novel c.83_85delAGA (p.Lys28del) in two families; a novel c.337G>C (p.Ala113Pro) in one family; and a known c.399_399+5del6 in one family. None of the variations were detected in 192 normal individuals. Two of the four probands had partial iris while the other two presented with full iris.
Conclusions:
We identified two novel and a known mutation of PAX6 in four probands with microcornea, accounting for 11.4% of microcorneas in this cohort. The findings not only expand the spectrum of PAX6 mutations, but also suggest that PAX6 mutations may be a common cause of microcornea.
Insights
Mutations in the paired box gene 6 (PAX6) were identified in patients with microcornea, suggesting PAX6 mutations may be a common cause of this condition. This study expands the known spectrum of PAX6 mutations associated with eye development.
Area of Science:
- Ophthalmology
- Genetics
- Developmental Biology
Background:
- Paired box gene 6 (PAX6) mutations are a primary cause of aniridia, occasionally linked to other ocular developmental anomalies like microcornea.
- Systemic evaluation of PAX6 in microcornea patients, where microcornea is the predominant feature, has not been previously reported.
Purpose of the Study:
- To investigate the role of PAX6 mutations in patients presenting with microcornea as the primary ocular abnormality.
- To identify and characterize PAX6 gene variations in a cohort of individuals with microcornea.
Main Methods:
- Sanger sequencing was employed to screen the coding regions of the PAX6 gene in genomic DNA from 35 families with microcornea.
- Novel PAX6 variations were further validated by screening in 192 healthy individuals.
- Bioinformatics analysis was utilized to assess the potential structural and pathological consequences of identified mutations.
Main Results:
- Three heterozygous PAX6 variations, including two novel mutations (c.83_85delAGA and c.337G>C) and one known mutation (c.399_399+5del6), were identified in four out of 35 probands.
- These identified PAX6 mutations were absent in 192 control individuals.
- The study found that PAX6 mutations accounted for 11.4% of microcornea cases within this cohort, with affected individuals exhibiting varying degrees of iris development.
Conclusions:
- The identification of novel and known PAX6 mutations in microcornea patients expands the mutational spectrum of this gene.
- The findings suggest that PAX6 mutations are a significant and potentially common genetic cause of microcornea.
- This research highlights the importance of genetic screening of PAX6 in individuals with microcornea, even in the absence of aniridia.
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