The electron microscopy techniques were used in various fields as an analytical technique under i... more The electron microscopy techniques were used in various fields as an analytical technique under in vitro conditions, which provides the sufficient resolution for better visualization and interpretation. This review gives a brief overview of the analytical application of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques and critical findings in different retinal pathologies. This review article aims to improvise understanding of retinal microstructures for clinicians which will help to improve the interpretation of the current advanced imaging techniques.
Retinopathy of prematurity (ROP) is a vasoproliferative eye disease in preterm infants. Based on ... more Retinopathy of prematurity (ROP) is a vasoproliferative eye disease in preterm infants. Based on its phenotypic similarities with familial exudative vitreo retinopathy (FEVR), the present study was conducted to screen the Norrin signalling pathway genes (already been implicated in FEVR) for understanding their involvement among Indian patients with ROP. The study cohort consisted of patients with ROP (n=246) and controls (n=300) that included full term (n=110) and preterm babies devoid of ROP (n=190). Screening of the NDP, FZD4, TSPAN12 genes were accomplished by resequencing the entire coding and untranslated regions (UTR). The genotype data of the patients with ROP were analysed in the background of their clinical manifestations and further analysed in conjunction with other available data on these genes worldwide. Two novel variants in intron 1 (IVS1 +16A>G) and 3'UTR (c.5 22T>C) along with a previously reported change in the 5'UTR (c.395_409del14bp) were observed i...
Retinopathy of prematurity (ROP) is a neurovascular complication in preterm babies, leading to se... more Retinopathy of prematurity (ROP) is a neurovascular complication in preterm babies, leading to severe visual impairment, but the underlying mechanisms are yet unclear. The present study aimed at unraveling the molecular mechanisms underlying the pathogenesis of ROP. A comprehensive screening of candidate genes in preterms with ROP (n = 189) and no-ROP (n = 167) was undertaken to identify variants conferring disease susceptibility. Allele and genotype frequencies, linkage disequilibrium and haplotypes were analyzed to identify the ROP-associated variants. Variants in CFH (p = 2.94 × 10-7), CFB (p = 1.71 × 10-5), FBLN5 (p = 9.2 × 10-4), CETP (p = 2.99 × 10-5), and CXCR4 (p = 1.32 × 10-8) genes exhibited significant associations with ROP. Further, a quantitative assessment of 27 candidate proteins and cytokines in the vitreous and tear samples of babies with severe ROP (n = 30) and congenital cataract (n = 30) was undertaken by multiplex bead arrays and further validated by western blo...
Primary congenital glaucoma (PCG) is a severe autosomal recessive ocular disorder associated with... more Primary congenital glaucoma (PCG) is a severe autosomal recessive ocular disorder associated with considerable clinical and genetic heterogeneity. Recently, rare heterozygous alleles in the angiopoietin receptor-encoding gene TEK were implicated in PCG. We undertook this study to ascertain the second mutant allele in a large cohort (n = 337) of autosomal recessive PCG cases that carried heterozygous TEK mutations. Our investigations revealed 12 rare heterozygous missense mutations in TEK by targeted sequencing. Interestingly, four of these TEK mutations (p.E103D, p.I148T, p.Q214P, and p.G743A) co-occurred with three heterozygous mutations in another major PCG gene CYP1B1 (p.A115P, p.E229K, and p.R368H) in five families. The parents of these probands harbored either of the heterozygous TEK or CYP1B1 alleles and were asymptomatic, indicating a potential digenic mode of inheritance. Furthermore, we ascertained the interactions of TEK and CYP1B1 by co-transfection and pull-down assays i...
Mutations in the Norrie disease pseudoglioma (NDP; Xp11.3) gene have been involved in retinal blo... more Mutations in the Norrie disease pseudoglioma (NDP; Xp11.3) gene have been involved in retinal blood vessel formation and neural differentiation and are implicated in familial exudative vitreoretinopathy (FEVR) cases. However, the role of the gene has not been explored in the Indian context. Thus, this study was designed to understand the involvement of NDP among Indian patients with FEVR. The study cohort comprised 225 subjects, including unrelated patients with FEVR (n = 110) and ethnically matched healthy subjects (n = 115) recruited from a tertiary eye care center in India. The entire coding regions, intron-exon boundaries, along with the 5' and 3' untranslated regions of NDP were screened with resequencing following standard protocols. The spectrum of the observed variants was analyzed in conjunction with data available from other populations. Eight potentially pathogenic mutations (p.His4ArgfsX21, p.Asp23GlufsX9, p.Ile48ValfsX55, p.His50Asp, p.Ser57*, p.Gly113Asp, p.Arg...
The fork-head transcription factor gene (FOXL2) gene has been implicated in Blepharophimosis Ptos... more The fork-head transcription factor gene (FOXL2) gene has been implicated in Blepharophimosis Ptosis Epicanthus Inversus Syndrome (BPES) type I and type II. The authors aimed to evaluate the involvement of FOXL2 in familial and sporadic cases of BPES in an Indian cohort. The present cohort comprised clinically well-characterised BPES cases that included six affected families, two sporadic cases and 60 unaffected normal controls. The 5' untranslated and coding region of FOXL2 was screened by resequencing and confirmed by restriction digestion. Further, genotype-phenotype correlations were done to understand the implications of the observed mutation. Six mutations were observed in eight cases (87.5%). These included a novel deletion (c.860delC), three previously reported duplications (c.663-692dup 30, c.672-701dup30 and c.843-859dup17), a frame shift (c.804dupC) and a homozygous missense mutation (p.E69K). The p.E69k mutation was seen in both heterozygous and homozygous form in a large four-generational family, and disease severity was found to be directly linked to the allelic dosage. Two SNPs (c.501C→T, c.536C→G) were also noted. An unusual coexistence of polycystic ovarian disease (PCOD) with BPES was also seen in one of the families. Mutations in the region downstream of the fork-head domain were predominantly responsible for BPES among Indian patients.
Single nucleotide polymorphisms (SNPs) in the LOXL1 gene have been implicated in exfoliation synd... more Single nucleotide polymorphisms (SNPs) in the LOXL1 gene have been implicated in exfoliation syndrome (XFS) and exfoliation glaucoma (XFG). We have shown that these SNPs are not associated with the primary glaucomas such as primary open-angle (POAG) glaucoma and primary angle-closure glaucoma (PACG). To further establish the specificity of LOXL1 SNPs for XFS and XFG, we determined whether these SNPs were involved in pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG). Three SNPs of LOXL1 (rs1048661, rs3825942, and rs2165241) were screened in a cohort of 78 unrelated and clinically well characterized glaucoma cases comprising of PG (n=44) and PDS (n=34) patients as well as 108 ethnically matched normal controls of Caucasian origin. The criteria for diagnosis of PDS/PG were Krukenberg spindle, hyperpigmentation of the trabecular meshwork, and wide open angle. Transillumination defects were detected by infrared pupillography, and the presence of a Zentmayer ring was consider...
Journal of American Association for Pediatric Ophthalmology and Strabismus, 2014
To report the various clinical presentations of congenital corneal anesthesia. The medical record... more To report the various clinical presentations of congenital corneal anesthesia. The medical records of children diagnosed with congenital corneal anesthesia between January 2006 and June 2012 at the L.V. Prasad Eye Institute, Hyderabad, India, were retrospectively reviewed for demographics and clinical characteristics. A total of 40 patients (29 males) were included. Median age at presentation was 12 months (interquartile range, 6-60 months). Bilateral involvement was noted in 28 cases (70%). Generalized pain insensitivity with anhidrosis was documented in 10 cases (25%). The spectrum of corneal lesions included geographic epithelial defects (32 eyes), sterile ulcers (15 eyes), sterile ulcers with hypopyon (11 eyes), secondary bacterial keratitis (2 eyes), superficial/ deep corneal vascularisation (5 eyes). Generalized anesthesia with self-mutilating behavior was recognized in 10 cases. In all cases, sterile corneal ulcers resolved on average 30 days after permanent 2/3-width paramedian tarsorrhapy. One eye progressed to the stage of anterior staphyloma and subsequently underwent auto evisceration. Four eyes that underwent keratoplasty for visual rehabilitation had poor outcomes. Accurate diagnosis, recognition of risk factors, and thorough neurological assessment is important for lessening long-term sequelae of congenital corneal anesthesia. Judicious use of tear substitutes and expedited tarsorrhaphy is crucial to restoration of useful vision in these children.
The ARMS2/HTRA1 genes at the 10q26 locus have been associated with risk of age-related macular de... more The ARMS2/HTRA1 genes at the 10q26 locus have been associated with risk of age-related macular degeneration (AMD), with the most significantly associated variants being A69S (rs10490924), del443ins54 (EU427539) and rs11200638. We wished to explore the association of the del443ins54 in two ethnically different populations from India and Australia. The del443ins54 was screened in a large cohort of ~1500 subjects from these two populations by a combination of PCR-based agarose gel electrophoresis and validated by resequencing. Statistical analysis comprised the calculations of allele, genotype and haplotype frequencies along with their p values and corresponding odds ratios (OR), and 95% confidence intervals (95% CI) and measures of linkage disequilibrium (LD). The del443ins54 was significantly associated with AMD in both the Indian (p=1.74 × 10(-13); OR = 2.80, 95%CI, 2.12-3.70) and Australian cohorts (p = 2.78 × 10(-30); OR = 3.15, 95%CI, 2.58-3.86). These associations were similar t...
Optometry and vision science : official publication of the American Academy of Optometry, 2014
To identify the spectrum of somatic mutations in an Asian Indian patient with uveal melanoma (UM)... more To identify the spectrum of somatic mutations in an Asian Indian patient with uveal melanoma (UM) without metastasis using exome sequencing. A 49-year-old man from India was diagnosed as having cilio-choroidal (uveal) melanoma (UM), without metastasis, in his right eye with the help of magnetic resonance imaging. This was later confirmed by histopathological evaluation. Two individuals from India with non-neoplastic blind eyes were recruited as controls. The affected eyes from the UM patient and the two control individuals were enucleated, and uveal tissues were collected. DNA was extracted from uveal tissue, and the matched blood sample from each of the three individuals was followed by exome sequencing. Statistical and bioinformatic analyses were done to identify somatic mutations and their putative associations with UM. Thirty-one somatic mutations (25 amino acid altering) in protein-coding (exonic) regions were detected in the UM patient. Of the amino acid-altering somatic mutat...
The electron microscopy techniques were used in various fields as an analytical technique under i... more The electron microscopy techniques were used in various fields as an analytical technique under in vitro conditions, which provides the sufficient resolution for better visualization and interpretation. This review gives a brief overview of the analytical application of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques and critical findings in different retinal pathologies. This review article aims to improvise understanding of retinal microstructures for clinicians which will help to improve the interpretation of the current advanced imaging techniques.
Retinopathy of prematurity (ROP) is a vasoproliferative eye disease in preterm infants. Based on ... more Retinopathy of prematurity (ROP) is a vasoproliferative eye disease in preterm infants. Based on its phenotypic similarities with familial exudative vitreo retinopathy (FEVR), the present study was conducted to screen the Norrin signalling pathway genes (already been implicated in FEVR) for understanding their involvement among Indian patients with ROP. The study cohort consisted of patients with ROP (n=246) and controls (n=300) that included full term (n=110) and preterm babies devoid of ROP (n=190). Screening of the NDP, FZD4, TSPAN12 genes were accomplished by resequencing the entire coding and untranslated regions (UTR). The genotype data of the patients with ROP were analysed in the background of their clinical manifestations and further analysed in conjunction with other available data on these genes worldwide. Two novel variants in intron 1 (IVS1 +16A>G) and 3'UTR (c.5 22T>C) along with a previously reported change in the 5'UTR (c.395_409del14bp) were observed i...
Retinopathy of prematurity (ROP) is a neurovascular complication in preterm babies, leading to se... more Retinopathy of prematurity (ROP) is a neurovascular complication in preterm babies, leading to severe visual impairment, but the underlying mechanisms are yet unclear. The present study aimed at unraveling the molecular mechanisms underlying the pathogenesis of ROP. A comprehensive screening of candidate genes in preterms with ROP (n = 189) and no-ROP (n = 167) was undertaken to identify variants conferring disease susceptibility. Allele and genotype frequencies, linkage disequilibrium and haplotypes were analyzed to identify the ROP-associated variants. Variants in CFH (p = 2.94 × 10-7), CFB (p = 1.71 × 10-5), FBLN5 (p = 9.2 × 10-4), CETP (p = 2.99 × 10-5), and CXCR4 (p = 1.32 × 10-8) genes exhibited significant associations with ROP. Further, a quantitative assessment of 27 candidate proteins and cytokines in the vitreous and tear samples of babies with severe ROP (n = 30) and congenital cataract (n = 30) was undertaken by multiplex bead arrays and further validated by western blo...
Primary congenital glaucoma (PCG) is a severe autosomal recessive ocular disorder associated with... more Primary congenital glaucoma (PCG) is a severe autosomal recessive ocular disorder associated with considerable clinical and genetic heterogeneity. Recently, rare heterozygous alleles in the angiopoietin receptor-encoding gene TEK were implicated in PCG. We undertook this study to ascertain the second mutant allele in a large cohort (n = 337) of autosomal recessive PCG cases that carried heterozygous TEK mutations. Our investigations revealed 12 rare heterozygous missense mutations in TEK by targeted sequencing. Interestingly, four of these TEK mutations (p.E103D, p.I148T, p.Q214P, and p.G743A) co-occurred with three heterozygous mutations in another major PCG gene CYP1B1 (p.A115P, p.E229K, and p.R368H) in five families. The parents of these probands harbored either of the heterozygous TEK or CYP1B1 alleles and were asymptomatic, indicating a potential digenic mode of inheritance. Furthermore, we ascertained the interactions of TEK and CYP1B1 by co-transfection and pull-down assays i...
Mutations in the Norrie disease pseudoglioma (NDP; Xp11.3) gene have been involved in retinal blo... more Mutations in the Norrie disease pseudoglioma (NDP; Xp11.3) gene have been involved in retinal blood vessel formation and neural differentiation and are implicated in familial exudative vitreoretinopathy (FEVR) cases. However, the role of the gene has not been explored in the Indian context. Thus, this study was designed to understand the involvement of NDP among Indian patients with FEVR. The study cohort comprised 225 subjects, including unrelated patients with FEVR (n = 110) and ethnically matched healthy subjects (n = 115) recruited from a tertiary eye care center in India. The entire coding regions, intron-exon boundaries, along with the 5' and 3' untranslated regions of NDP were screened with resequencing following standard protocols. The spectrum of the observed variants was analyzed in conjunction with data available from other populations. Eight potentially pathogenic mutations (p.His4ArgfsX21, p.Asp23GlufsX9, p.Ile48ValfsX55, p.His50Asp, p.Ser57*, p.Gly113Asp, p.Arg...
The fork-head transcription factor gene (FOXL2) gene has been implicated in Blepharophimosis Ptos... more The fork-head transcription factor gene (FOXL2) gene has been implicated in Blepharophimosis Ptosis Epicanthus Inversus Syndrome (BPES) type I and type II. The authors aimed to evaluate the involvement of FOXL2 in familial and sporadic cases of BPES in an Indian cohort. The present cohort comprised clinically well-characterised BPES cases that included six affected families, two sporadic cases and 60 unaffected normal controls. The 5' untranslated and coding region of FOXL2 was screened by resequencing and confirmed by restriction digestion. Further, genotype-phenotype correlations were done to understand the implications of the observed mutation. Six mutations were observed in eight cases (87.5%). These included a novel deletion (c.860delC), three previously reported duplications (c.663-692dup 30, c.672-701dup30 and c.843-859dup17), a frame shift (c.804dupC) and a homozygous missense mutation (p.E69K). The p.E69k mutation was seen in both heterozygous and homozygous form in a large four-generational family, and disease severity was found to be directly linked to the allelic dosage. Two SNPs (c.501C→T, c.536C→G) were also noted. An unusual coexistence of polycystic ovarian disease (PCOD) with BPES was also seen in one of the families. Mutations in the region downstream of the fork-head domain were predominantly responsible for BPES among Indian patients.
Single nucleotide polymorphisms (SNPs) in the LOXL1 gene have been implicated in exfoliation synd... more Single nucleotide polymorphisms (SNPs) in the LOXL1 gene have been implicated in exfoliation syndrome (XFS) and exfoliation glaucoma (XFG). We have shown that these SNPs are not associated with the primary glaucomas such as primary open-angle (POAG) glaucoma and primary angle-closure glaucoma (PACG). To further establish the specificity of LOXL1 SNPs for XFS and XFG, we determined whether these SNPs were involved in pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG). Three SNPs of LOXL1 (rs1048661, rs3825942, and rs2165241) were screened in a cohort of 78 unrelated and clinically well characterized glaucoma cases comprising of PG (n=44) and PDS (n=34) patients as well as 108 ethnically matched normal controls of Caucasian origin. The criteria for diagnosis of PDS/PG were Krukenberg spindle, hyperpigmentation of the trabecular meshwork, and wide open angle. Transillumination defects were detected by infrared pupillography, and the presence of a Zentmayer ring was consider...
Journal of American Association for Pediatric Ophthalmology and Strabismus, 2014
To report the various clinical presentations of congenital corneal anesthesia. The medical record... more To report the various clinical presentations of congenital corneal anesthesia. The medical records of children diagnosed with congenital corneal anesthesia between January 2006 and June 2012 at the L.V. Prasad Eye Institute, Hyderabad, India, were retrospectively reviewed for demographics and clinical characteristics. A total of 40 patients (29 males) were included. Median age at presentation was 12 months (interquartile range, 6-60 months). Bilateral involvement was noted in 28 cases (70%). Generalized pain insensitivity with anhidrosis was documented in 10 cases (25%). The spectrum of corneal lesions included geographic epithelial defects (32 eyes), sterile ulcers (15 eyes), sterile ulcers with hypopyon (11 eyes), secondary bacterial keratitis (2 eyes), superficial/ deep corneal vascularisation (5 eyes). Generalized anesthesia with self-mutilating behavior was recognized in 10 cases. In all cases, sterile corneal ulcers resolved on average 30 days after permanent 2/3-width paramedian tarsorrhapy. One eye progressed to the stage of anterior staphyloma and subsequently underwent auto evisceration. Four eyes that underwent keratoplasty for visual rehabilitation had poor outcomes. Accurate diagnosis, recognition of risk factors, and thorough neurological assessment is important for lessening long-term sequelae of congenital corneal anesthesia. Judicious use of tear substitutes and expedited tarsorrhaphy is crucial to restoration of useful vision in these children.
The ARMS2/HTRA1 genes at the 10q26 locus have been associated with risk of age-related macular de... more The ARMS2/HTRA1 genes at the 10q26 locus have been associated with risk of age-related macular degeneration (AMD), with the most significantly associated variants being A69S (rs10490924), del443ins54 (EU427539) and rs11200638. We wished to explore the association of the del443ins54 in two ethnically different populations from India and Australia. The del443ins54 was screened in a large cohort of ~1500 subjects from these two populations by a combination of PCR-based agarose gel electrophoresis and validated by resequencing. Statistical analysis comprised the calculations of allele, genotype and haplotype frequencies along with their p values and corresponding odds ratios (OR), and 95% confidence intervals (95% CI) and measures of linkage disequilibrium (LD). The del443ins54 was significantly associated with AMD in both the Indian (p=1.74 × 10(-13); OR = 2.80, 95%CI, 2.12-3.70) and Australian cohorts (p = 2.78 × 10(-30); OR = 3.15, 95%CI, 2.58-3.86). These associations were similar t...
Optometry and vision science : official publication of the American Academy of Optometry, 2014
To identify the spectrum of somatic mutations in an Asian Indian patient with uveal melanoma (UM)... more To identify the spectrum of somatic mutations in an Asian Indian patient with uveal melanoma (UM) without metastasis using exome sequencing. A 49-year-old man from India was diagnosed as having cilio-choroidal (uveal) melanoma (UM), without metastasis, in his right eye with the help of magnetic resonance imaging. This was later confirmed by histopathological evaluation. Two individuals from India with non-neoplastic blind eyes were recruited as controls. The affected eyes from the UM patient and the two control individuals were enucleated, and uveal tissues were collected. DNA was extracted from uveal tissue, and the matched blood sample from each of the three individuals was followed by exome sequencing. Statistical and bioinformatic analyses were done to identify somatic mutations and their putative associations with UM. Thirty-one somatic mutations (25 amino acid altering) in protein-coding (exonic) regions were detected in the UM patient. Of the amino acid-altering somatic mutat...
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Papers by Inderjeet Kaur