Chikezie Grand Ihesiulor and Udo A Ubani

University of Manchester, Uinted Kingdom and Abia State University Uturu, Nigeria

Title: Molecular basis of congenital glaucoma


Chikezie Grand Ihesiulor was born in Port Harcourt, Nigeria, in 1986. He received the O.D. Doctor of Optometry degree in Optometry from Abia State University, Uturu,
Nigeria, in 2008 and the MSc in Investigative Ophthalmology and Vision Sciences in The University of Manchester, UK in 2013. In 2015, I joined the Department of
Optometry, Abia State University, as a Lecturer. His current research interests include glaucoma, ocular trauma, ocular genetics, preventive optometry, visual psychology
and psychopathology. Dr. Chikezie is a member of the Nigerian Optometric Association (NOA) and the Optometrist and Dispensing Opticians Registration Board of Nigeria.
He is the CEO of Healthy-hope Lifestyle Centre, Nigeria. He was awarded the best clinician by the President, NOA in 2009 and has joined and led several community
health care teams in Nigeria and UK to offer free medical and eye health care services. He is an innovative researcher and is currently pursuing his Ph.D. in Optometry in
The University of Manchester, UK.


Purpose: The purpose of this study was to detect pathogenic mutations in cytochrome P450, family 1, subfamily B, polypeptide
1 (CYP1B1) gene in 19 sporadic primary congenital glaucoma (PCG) cases and to identify patients lacking CYP1B1 mutations.
Secondly, to conduct an in silico analysis of exome sequencing data of variants common to three related pigment dispersion
syndrome (PDS) patients.
Methods: CYP1B1 exon 2 and the coding part of exon 3 of 15 participants were amplified by polymerase chain reaction and
amplicons were sequenced by Sanger sequencing. Sequencing data was analyzed to identify the gene mutations or SNPs. Second,
the exome sequencing data of the PDS patients combined was analyzed in-house by bioinformaticians and further filtered
manually to identify candidate genes for PDS.
Results: Four previously reported PCG-associated CYP1B1 mutations (c.1159G>A; p.E387K, c.230T>C; p.L77P, c.1103G>A;
p.R368H and c.1568G>A; p.R523K) were found in four patients out of the 15 fully ‘sequenced’ patients. Also, 10 previously
reported single nucleotide polymorphisms and two novel noncoding variants were identified. Second, 21 candidate genes were
found after filtering using various databases (OMIM & GeneDistiller). Nine genes (TPCN2, TYR, PAX6, DICER 1, FOXE3, TGIF1,
TCF4, RPGR and CNGB3) may be of more importance since they are associated with ocular diseases.
Conclusion: The relatively low percentage of PCG patients having CYP1B1 mutations (4/15=26.6%) demonstrates that other
known and unknown genes may contribute to PCG pathogenesis. Lack of CYP1B1 gene mutations in some patients stresses the
need to identify other responsible candidates. More analysis may be needed and the genes identified may be screened in future in
other PDS patients to study PDS genetics.