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Mutation spectrum of CYP1B1 in North Indian congenital glaucoma patients.

Tanwar M, Dada T, Sihota R, Das TK, Yadav U, Dada R - Mol. Vis. (2009)

Bottom Line: However, on sequencing, we found that 23/50 (46%) harbored the CYPIB1 mutations.Ter@223 was found in 18%, p.R390H in 16%, and p.R368H in 8% of cases.Ter@223 was found to be the most prevalent mutation in our patients while p.R368H was most prevalent in southern India.

View Article: PubMed Central - PubMed

Affiliation: Laboratory for Molecular Reproduction and Genetics, Department of Anatomy, AIIMS, New Delhi, India.

ABSTRACT

Purpose: Mutations in Cytochrome P450 (CYP1B1) are a predominant cause of congenital glaucoma. This study was planned with the aim to identify the mutation profile of CYP1B1 in North Indian primary congenital glaucoma (PCG) patients.

Methods: After ethical clearance, 50 congenital glaucoma patients and 50 ethnically matched controls were recruited in this study. Genomic DNA was isolated from the blood and trabecular meshwork, and CYP1B1 was screened for the six most prevalent mutations (termination at 223 [Ter@223], Gly61Glu, Pro193Leu, Glu229Lys, Arg368His, and Arg390Cys) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). DNA sequencing was done to identify other mutations and for confirmation of RFLP positive samples.

Results: On PCR-RFLP, 21/50 cases (42%) were found positive for one or more of these mutations. However, on sequencing, we found that 23/50 (46%) harbored the CYPIB1 mutations. Ter@223 was found in 18%, p.R390H in 16%, and p.R368H in 8% of cases. Three novel mutations, p.L24R, p.F190L, and p.G329D, were identified by DNA sequencing. Leucine, phenylalanine, and glycine are conserved at the 24th, 190th, and 329th position in the CYP1B1 protein in different species, suggestive of important functions at these loci. Ter@223 was found to be the most prevalent mutation in our patients while p.R368H was most prevalent in southern India. The difference in frequency and mutation profile may be due to the heterogeneous Indian population. Pathogenic CYP1B1 mutations impair anterior chamber development and differentiation by blocking the aqueous outflow and raising intraocular pressure (IOP).

Conclusions: Three novel mutations were identified in this study. Studies of pathogenic sequence variants in CYP1B1 in different populations may contribute to a better understanding of the disease pathogenesis. This may lead to the development of novel therapeutic approaches in the near future.

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Related in: MedlinePlus

DNA sequence from intron 1 and exon 2 of CYP1B1. A: Reference sequence derived from a control is shown. B: DNA sequence derived from PCG 040 shows the homozygous C>T (38156048C→T) nucleotide change, an already reported polymorphism (rs2617266).
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f5: DNA sequence from intron 1 and exon 2 of CYP1B1. A: Reference sequence derived from a control is shown. B: DNA sequence derived from PCG 040 shows the homozygous C>T (38156048C→T) nucleotide change, an already reported polymorphism (rs2617266).

Mentions: In addition to pathogenic mutations, six already reported single nucleotide polymorphisms [8] were identified in the less conserved region of CYP1B1 both in the controls and patients. These polymorphisms were p.R48G, p.A119S, p.L432V, p.D449D, p.N453S, and rs2617266. They were revealed by DNA sequencing. rs2617266 (38156104C→T; Figure 5) was identified in two patients (PCG 039 and PCG 040). All patients with a CYP1B1 mutation also had L432V polymorphism. These polymorphisms were present in controls.


Mutation spectrum of CYP1B1 in North Indian congenital glaucoma patients.

Tanwar M, Dada T, Sihota R, Das TK, Yadav U, Dada R - Mol. Vis. (2009)

DNA sequence from intron 1 and exon 2 of CYP1B1. A: Reference sequence derived from a control is shown. B: DNA sequence derived from PCG 040 shows the homozygous C>T (38156048C→T) nucleotide change, an already reported polymorphism (rs2617266).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2697458&req=5

f5: DNA sequence from intron 1 and exon 2 of CYP1B1. A: Reference sequence derived from a control is shown. B: DNA sequence derived from PCG 040 shows the homozygous C>T (38156048C→T) nucleotide change, an already reported polymorphism (rs2617266).
Mentions: In addition to pathogenic mutations, six already reported single nucleotide polymorphisms [8] were identified in the less conserved region of CYP1B1 both in the controls and patients. These polymorphisms were p.R48G, p.A119S, p.L432V, p.D449D, p.N453S, and rs2617266. They were revealed by DNA sequencing. rs2617266 (38156104C→T; Figure 5) was identified in two patients (PCG 039 and PCG 040). All patients with a CYP1B1 mutation also had L432V polymorphism. These polymorphisms were present in controls.

Bottom Line: However, on sequencing, we found that 23/50 (46%) harbored the CYPIB1 mutations.Ter@223 was found in 18%, p.R390H in 16%, and p.R368H in 8% of cases.Ter@223 was found to be the most prevalent mutation in our patients while p.R368H was most prevalent in southern India.

View Article: PubMed Central - PubMed

Affiliation: Laboratory for Molecular Reproduction and Genetics, Department of Anatomy, AIIMS, New Delhi, India.

ABSTRACT

Purpose: Mutations in Cytochrome P450 (CYP1B1) are a predominant cause of congenital glaucoma. This study was planned with the aim to identify the mutation profile of CYP1B1 in North Indian primary congenital glaucoma (PCG) patients.

Methods: After ethical clearance, 50 congenital glaucoma patients and 50 ethnically matched controls were recruited in this study. Genomic DNA was isolated from the blood and trabecular meshwork, and CYP1B1 was screened for the six most prevalent mutations (termination at 223 [Ter@223], Gly61Glu, Pro193Leu, Glu229Lys, Arg368His, and Arg390Cys) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). DNA sequencing was done to identify other mutations and for confirmation of RFLP positive samples.

Results: On PCR-RFLP, 21/50 cases (42%) were found positive for one or more of these mutations. However, on sequencing, we found that 23/50 (46%) harbored the CYPIB1 mutations. Ter@223 was found in 18%, p.R390H in 16%, and p.R368H in 8% of cases. Three novel mutations, p.L24R, p.F190L, and p.G329D, were identified by DNA sequencing. Leucine, phenylalanine, and glycine are conserved at the 24th, 190th, and 329th position in the CYP1B1 protein in different species, suggestive of important functions at these loci. Ter@223 was found to be the most prevalent mutation in our patients while p.R368H was most prevalent in southern India. The difference in frequency and mutation profile may be due to the heterogeneous Indian population. Pathogenic CYP1B1 mutations impair anterior chamber development and differentiation by blocking the aqueous outflow and raising intraocular pressure (IOP).

Conclusions: Three novel mutations were identified in this study. Studies of pathogenic sequence variants in CYP1B1 in different populations may contribute to a better understanding of the disease pathogenesis. This may lead to the development of novel therapeutic approaches in the near future.

Show MeSH
Related in: MedlinePlus