title: Mutational spectrum of the CYP1B1 gene in Pakistani patients with primary congenital glaucoma: novel variants and genotype-phenotype correlations.
abstract: OBJECTIVE
  This study aimed to investigate the role of CYP1B1 mutations in primary congenital glaucoma (PCG) in Pakistani patients.
  
  
  METHODS
  After consent was received, 20 families with at least more than one member affected with primary congenital glaucoma were enrolled in the study. The disease was confirmed with standard ophthalmological investigations. Genomic DNA was extracted from whole blood for localization of linkage and sequencing. Bioinformatics tools were used to assess the predicted pathological role of novel variants.
  
  
  RESULTS
  Ten out of 20 families (50%, 10/20) showed homozygosity with CYP1B1-linked short tandem repeat (STR) markers. On direct sequencing of the CYP1B1 gene in the linked families, six mutations, including two novel pathogenic variants, were identified. p. R390H was the most frequently found mutation in five families (50%, 5/10), whereas c.868_869insC, p.E229K, and p.A115P were found once in three families. Two novel mutations, a missense mutation (p.G36D) and an in-frame deletion mutation (p.G67-A70del), were segregated with disease phenotype in two families. Age of disease onset was congenital in all mutations; however, disease severity and response to clinical interventions varied among the mutations and families. Haplotype analysis using five polymorphisms revealed a distinct haplotype for a common mutation.
  
  
  CONCLUSIONS
  This is the largest cohort of Pakistani patients with PCG to be genetically screened for CYP1B1 mutations. Identifying common mutation and genotype-phenotype correlations may help in genetic testing and better prognosis for the disease. Novel mutations identified in the study may help in better understanding the pathophysiology of CYP1B1-associated glaucoma.
authors.affiliation: Molecular Biology and Genetics Department, Medical Research Center, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan.
authors.forename: Shakeel Ahmed
authors.initials: SA
authors.lastname: Sheikh
authors.affiliation: Molecular Biology and Genetics Department, Medical Research Center, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan ; Department of Pathology, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan.
authors.forename: Ali Muhammad
authors.initials: AM
authors.lastname: Waryah
authors.affiliation: Department of Ophthalmology, Liaquat University of Medical and Health Sciences, Hyderabad, Pakistan.
authors.forename: Ashok Kumar
authors.initials: AK
authors.lastname: Narsani
authors.affiliation: Molecular Biology and Genetics Department, Medical Research Center, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan.
authors.forename: Hina
authors.initials: H
authors.lastname: Shaikh
authors.affiliation: Department of Ophthalmology, Liaquat University of Medical and Health Sciences, Hyderabad, Pakistan.
authors.forename: Imtiaz Ahmed
authors.initials: IA
authors.lastname: Gilal
authors.affiliation: Department of Ophthalmology, Liaquat University of Medical and Health Sciences, Hyderabad, Pakistan.
authors.forename: Khairuddin
authors.initials: K
authors.lastname: Shah
authors.affiliation: Departments of Bioinformatics & Biotechnology, Government College University Faisalabad, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Qasim
authors.affiliation: Molecular Biology and Genetics Department, Medical Research Center, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan.
authors.forename: Azam Iqbal
authors.initials: AI
authors.lastname: Memon
authors.affiliation: Department of Ophthalmology, Liaquat University of Medical and Health Sciences, Hyderabad, Pakistan.
authors.forename: Pitambar
authors.initials: P
authors.lastname: Kewalramani
authors.affiliation: Molecular Biology and Genetics Department, Medical Research Center, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan ; Department of Pathology, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan.
authors.forename: Naila
authors.initials: N
authors.lastname: Shaikh
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D001189:Aryl Hydrocarbon Hydroxylases / Q000737:chemistry / Q000235:genetics*; D065633:Cytochrome P-450 CYP1B1; D004596:Electroretinography; D005260:Female; D056726:Genetic Association Studies; D005901:Glaucoma / Q000151:congenital* / Q000201:enzymology / Q000235:genetics* / Q000503:physiopathology; D006239:Haplotypes / Q000235:genetics; D006720:Homozygote; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D010154:Pakistan; D010375:Pedigree; D055815:Young Adult
chemical_list: D001189:Aryl Hydrocarbon Hydroxylases; C585496:CYP1B1 protein, human; D065633:Cytochrome P-450 CYP1B1