A Novel CRYBB2 Silent Variant in Autosomal Dominant Congenital Cataracts (ADCC) in Pakistani families

Objective

Congenital Cataract is a type of ophthalmic genetic disorder that appears at birth or in early childhood. Among 30 genes, CRYBB2 is one of the most common and a water-soluble protein of lens's that code for the βB2-crystallin. This study aimed to investigate the novel silent mutation in CRYBB2 of exon six in the Pakistani families of Autosomal Dominant Congenital Cataracts (ADCC).

Methods

It is a family-based study that presents three to five-generations of two Pakistani families. Data and blood samples from the families were collected from January to August 2019 from LRBT (Layton Rahmatullah Benevolent Trust) Hospital, Mansehra, Pakistan. We only included patients >15 years old. Before enrollment in the current study, each patient obtained a thorough optical examination. Samples were moved to the molecular lab using the collection and storage method. The phenol-chloroform technique was used to extract the DNA. The technique of Sanger sequencing was used to find any potential mutation in some of the selected families. Statistical and bioinformatics analysis were carried out.

Results

By using bioinformatics tools, the novel silent mutation was identified. Heterozygous silent mutation of CRYBB2 of exon 6 (c. 495G>A) was detected by the alignment of sequences. Computational prediction program did not predict the silent mutation.

Conclusion

This study investigated a novel important sequence variant in the beta-crystalline protein that causes autosomal dominant congenital cataract (ADCC) in Pakistani families. Thus, our study enlarges the CRYBB2 mutation spectrum and associated phenotypes to help clinical diagnosis of human genetic diseases.