Investigation of mutational spectrum in cytochrome P4501B1 (CYP1B1) as the principal cause of primary congenital glaucoma

Tazeen Zahid; Muhammad Umer Khan; Aymn Zulfiqar; Fatima Jawad; Anosh Saleem; Ahmad Raza Khan

doi:10.12669/pjms.39.2.7081

Investigation of mutational spectrum in cytochrome P4501B1 (CYP1B1) as the principal cause of primary congenital glaucoma

Pak J Med Sci. 2023 Mar-Apr;39(2):409-416. doi: 10.12669/pjms.39.2.7081.

Authors

Tazeen Zahid¹, Muhammad Umer Khan², Aymn Zulfiqar³, Fatima Jawad⁴, Anosh Saleem⁵, Ahmad Raza Khan⁶

Affiliations

¹ Tazeen Zahid DMLS, MPhil Scholar., Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan.
² Muhammad Umer Khan, MPhil, PhD., Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan.
³ Aymn Zulfiqar, DMLS., University Institute of Medical Laboratory Technology, Faculty of Allied Health Sciences, The University of Lahore, Lahore, Pakistan.
⁴ Fatima Jawad, DMLS., University Institute of Medical Laboratory Technology, Faculty of Allied Health Sciences, The University of Lahore, Lahore, Pakistan.
⁵ Anosh Saleem, DMLS., University Institute of Medical Laboratory Technology, Faculty of Allied Health Sciences, The University of Lahore, Lahore, Pakistan.
⁶ Ahmad Raza Khan, DMLS., University Institute of Medical Laboratory Technology, Faculty of Allied Health Sciences, The University of Lahore, Lahore, Pakistan.

Abstract

Objective: To identify the genetic variants in the CYP1B1 gene associated with Primary Congenital Glaucoma (PCG) and to predict its pathological effect.

Method: A descriptive study was conducted in the time period of nine months (September 2021-May 2022) after the ethical approval was taken from The Children Hospital and Institute of Child Health (CH & ICH). Two milliliters of the blood sample from PCG-affected individuals were collected in EDTA vacutainers and genomic DNA was extracted by a phenol-chloroform method. The semi-quantification of extracted DNA was done by agarose gel electrophoresis. PCR amplification was performed by specific primers of CYP1B1 gene then termination sequencing (di-deoxy) was done to detect the genetic variants. Different bioinformatics tools such as BLAST, Ensembl, Clustal Omega, Polyphen and SIFT were used for the further analysis of mutation causing the disease.

Result: A total of 85% of patients were bilaterally affected, while 15% were unilaterally affected. Mutation analysis identified five non related known variants. Two missense mutations (c.355 G/T p.A119S and c.685G/A p.E229K) occurred in 94% patients and intragenic SNP occurred in 29% patients along with the 1% somatic (c.693C/A p.F231L) and stop gained mutation (c.840C/A p.C280*).

Conclusion: Genetic analysis in the current study showed that 85% of PCG affected patients were due to the CYP1B1 mutation, and disease heterogeneity might be reduced through genetic counseling.

Keywords: Consanguinity; Cytochrome P450; Intraocular pressure; Mutation; Primary congenital glaucoma.