Stage of visual field loss and age at diagnosis in 1988 patients with different glaucomas: implications for glaucoma screening and driving ability.

PURPOSE: To compare stage of visual field loss (VFL) and age at diagnosis between patients with different types of glaucoma with regard to glaucoma screening and driving ability. METHODS: In a cross-sectional study of 1988 consecutive patients with different types of glaucoma VFL at diagnosis and age at diagnosis were assessed. Patients with binocular advanced or severe VFL were classified unable, patients with no VFL in one eye and VFL I-V (Aulhorn classification) in the other eye able, all other constellations questionably able to drive. RESULTS: There were significant differences in age at diagnosis between different glaucomas and between patients with different stages of VFL at diagnosis. Age-related assessment of VFL at diagnosis in normal tension glaucoma (NTG) compared to primary open-angle glaucoma (POAG) showed that NTG is not a disease of the elderly but a disease with late diagnosis at severe VFL. In POAG a solely age-related glaucoma screening, e.g. from the age of 50 years, does not sufficiently lead to diagnosis at an early stage of the disease. In POAG solely based on binocular VFL 11.5% of patients were judged unable, 29.2% questionably able to drive, in NTG 19.6%/43.1%, pigmentary glaucoma 16%/22%, pseudoexfoliation glaucoma 9.1%/16.7%, and in primary angle-closure glaucoma 14.6%/30%. CONCLUSIONS: Depending on type of glaucoma more than 50% of patients require counselling regarding safe driving as part of clinical care. A disease-specific, age-related perimetric examination considering additional risk factors like family history of glaucoma is essential for early detection of glaucoma and road safety.

Optic Disc Drusen and Family History of Glaucoma-Results of a Patient-directed Survey.

PURPOSE: Prospective evaluation of family history (FH) of glaucoma and FH of optic disc drusen (ODD) in patients with sonographically confirmed ODD. PATIENTS AND METHODS: A total of 87 patients with ODD interviewed all their first-degree and second-degree relatives using a detailed questionnaire on whether an ophthalmologist had diagnosed or excluded glaucoma or ocular hypertension (OH). Using a second questionnaire, 62 of these patients also provided information about ODD in their FH. Control groups for FH of glaucoma consisted of 2170 patients with glaucoma or OH evaluated with the same methods and identical questions for FH of glaucoma in a previous study, and of 176 healthy individuals without glaucoma or ODD who were interviewed on family history of glaucoma. RESULTS: Glaucoma in FH was significantly more frequent in patients with ODD with an incidence of 20.7% compared with healthy controls with an incidence of 2.8%, and half as frequent as in glaucoma patients with an incidence of 40%. ODD in FH were found in 9.7% of patients with ODD. CONCLUSIONS: As there is a high frequency of family history of glaucoma in patients with ODD, evaluation of FH of ODD and FH of glaucoma is essential in patients with ODD. Glaucoma in FH of ODD patients requires intraocular pressure monitoring and whenever deemed beneficial timely initiation of intraocular pressure-lowering therapy.

Migraine and Vasospasm in Glaucoma: Age-Related Evaluation of 2027 Patients With Glaucoma or Ocular Hypertension.

PURPOSE: To evaluate frequency of migraine, vasospasm (VS), family history (FH) of migraine, and family history of glaucoma (FHG) in different types of glaucoma in relation to age and stage of visual field loss (VFL) at diagnosis. METHODS: A total of 2170 patients with glaucoma or ocular hypertension (OH) were interviewed by using standardized questions concerning FHG, age at diagnosis, and potential risk factors, including migraine and VS. Of 2027 patients providing information on migraine, 1244 had primary open-angle glaucoma (POAG), 140 normal tension glaucoma (NTG), 49 pigmentary glaucoma, 64 pseudoexfoliation glaucoma (PEX), 138 OH, and 218 primary angle closure glaucoma (PACG). RESULTS: Of all patients, 13.7% reported migraine, 19.0% VS, 30.8% FH of migraine, and 40.3% FHG. Patients with FHG had a significantly higher frequency of migraine than patients without FHG (15.7% vs. 12.3%, P = 0.02). Migraine was significantly more frequent in NTG (21.4%) than POAG (13.1%; P = 0.01), PEX (7.8%; P = 0.02), and PACG (10.1%; P = 0.004). Compared to patients with POAG, patients with NTG had a 63.5% higher age-corrected probability for migraine (P = 0.007). There was no evidence for migraine or VS being prognostic factors regarding the extent of VFL at diagnosis. Migraine and VS were significantly more frequent in females. CONCLUSIONS: The higher frequency of migraine and VS in females could contribute to the female preponderance in NTG. Our findings suggest an association of NTG and migraine and a common, possibly polygenetic, vascular etiology of these two diseases both with familial predisposition.

Results of a patient-directed survey on frequency of family history of glaucoma in 2170 patients.

PURPOSE: To evaluate in different types of glaucoma frequency of family history of glaucoma (FHG), age at diagnosis, glaucoma risk in relatives, and acceptance rate of genetic glaucoma tests. To assess stage of visual field loss (VFL) in relation to FHG. METHODS: Using standardized questions whether an ophthalmologist had found or excluded glaucoma or ocular hypertension (OH), 2170 patients with glaucoma or OH interviewed all their first and second degree relatives. One thousand three hundred thirty-eight patients had POAG, 233 primary angle closure glaucoma (PACG), 148 OH, 153 normal tension glaucoma (NTG), 50 pigmentary glaucoma (PG), and 66 pseudoexfoliation glaucoma (PEX). RESULTS: Frequency of FHG was 40% in POAG, without significant differences compared with NTG (P = 0.08), OH (P = 0.5), PACG (P = 0.4), and PG (P = 0.6). There were significant differences in age at diagnosis between the glaucomas (smallest between group P < 0.0001). Patients with FHG were significantly younger at diagnosis than patients without FHG in all types of glaucoma (all P values ≤ 0.03), except NTG and PEX. Patients' siblings and mothers had the highest detection probability for glaucoma in POAG and OH. There was no significant relation between stage of VFL and FHG in POAG (P = 0.6). Sixty-eight percent of patients would participate in genetic glaucoma tests. CONCLUSIONS: There is a similarly high genetic disposition in all types of glaucoma. Disease risk was especially high in mothers and siblings. In patients with FHG, knowledge of genetic disposition of the glaucomas may have led to earlier diagnosis. This highlights the need for glaucoma awareness campaigns.

Common genetic determinants of intraocular pressure and primary open-angle glaucoma.

Intraocular pressure (IOP) is a highly heritable risk factor for primary open-angle glaucoma and is the only target for current glaucoma therapy. The genetic factors which determine IOP are largely unknown. We performed a genome-wide association study for IOP in 11,972 participants from 4 independent population-based studies in The Netherlands. We replicated our findings in 7,482 participants from 4 additional cohorts from the UK, Australia, Canada, and the Wellcome Trust Case-Control Consortium 2/Blue Mountains Eye Study. IOP was significantly associated with rs11656696, located in GAS7 at 17p13.1 (p=1.4×10(-8)), and with rs7555523, located in TMCO1 at 1q24.1 (p=1.6×10(-8)). In a meta-analysis of 4 case-control studies (total N = 1,432 glaucoma cases), both variants also showed evidence for association with glaucoma (p=2.4×10(-2) for rs11656696 and p=9.1×10(-4) for rs7555523). GAS7 and TMCO1 are highly expressed in the ciliary body and trabecular meshwork as well as in the lamina cribrosa, optic nerve, and retina. Both genes functionally interact with known glaucoma disease genes. These data suggest that we have identified two clinically relevant genes involved in IOP regulation.

A splice site mutation in the PAX6 gene which induces exon skipping causes autosomal dominant inherited aniridia.

PURPOSE: To identify the underlying genetic cause in a two generation German family diagnosed with isolated aniridia. METHODS: All patients underwent full ophthalmic examination. Mutation screening of the paired box gene 6 (PAX6) was performed by bidirectional Sanger sequencing. A minigene assay was applied to analyze transcript processing of mutant and wildtype PAX6 variants in HEK293 cells. RESULTS: We identified a PAX6 sequence variant at the splice donor site (+5) of intron 12. This variant has been described before in another family with aniridia but has not been characterized at the transcript level. We could demonstrate that the mutant allele causes the skipping of exon 12 during transcript processing. The mutation is predicted to result in a 'run on' translation past the normal translational stop codon. CONCLUSIONS: A splice site mutation resulting in exon skipping was found in a family with autosomal dominant aniridia. The mutation is predicted to result in an enlarged protein with an extra COOH-terminal domain. This very likely affects the transactivation properties of the PAX6 protein.

Variants in ASB10 are associated with open-angle glaucoma.

The molecular events responsible for obstruction of aqueous humor outflow and the loss of retinal ganglion cells in glaucoma, one of the main causes of blindness worldwide, remain poorly understood. We identified a synonymous variant, c.765C>T (Thr255Thr), in ankyrin repeats and suppressor of cytokine signaling box-containing protein 10 (ASB10) in a large family with primary open angle glaucoma (POAG) mapping to the GLC1F locus. This variant affects an exon splice enhancer site and alters mRNA splicing in lymphoblasts of affected family members. Systematic sequence analysis in two POAG patient groups (195 US and 977 German) and their respective controls (85 and 376) lead to the identification of 26 amino acid changes in 70 patients (70 of 1172; 6.0%) compared with 9 in 13 controls (13 of 461; 2.8%; P = 0.008). Molecular modeling suggests that these missense variants change ASB10 net charge or destabilize ankyrin repeats. ASB10 mRNA and protein were found to be strongly expressed in trabecular meshwork, retinal ganglion cells and ciliary body. Silencing of ASB10 transcripts in perfused anterior segment organ culture reduced outflow facility by ∼50% compared with control-infected anterior segments (P = 0.02). In conclusion, genetic and molecular analyses provide evidence for ASB10 as a glaucoma-causing gene.

Glaucoma and frequency of ocular and general diseases in 30 patients with aniridia: a clinical study.

PURPOSE: To evaluate the following in patients with aniridia: age at first examination at the University Eye Hospital and age at diagnosis of glaucoma; visual acuity; frequency of family history of aniridia; and frequency of ocular and general diseases associated with aniridia. METHODS: This was a consecutive examination of 30 unrelated patients with aniridia and retrospective evaluation of ophthalmologic, pediatric, and internal findings. The relative frequency of age at glaucoma diagnosis within decades was evaluated for the 20 patients with aniridia and glaucoma. Statistical analysis was performed using the Mann-Whitney test. RESULTS: Relative frequency of the age of patients with aniridia at time of glaucoma diagnosis within the following decades was as follows: from birth to 9 years: 15%, 10-19: 15%, 20-29: 15%, 30-39: 15%, 40-49: 35%, and 50-59: 5%. Visual acuity in the better eye of 20/100 or less was found in 60%. Family history of aniridia was found in 33.3% of patients, with 1-4 relatives with aniridia. A total of 76.7% of patients had congenital cataract, and 66.7% had glaucoma. Mean maximum intraocular pressure of the 20 patients with glaucoma was 35.9 mmHg in the right and 32.6 mmHg in the left eye. A total of 53.3% had nystagmus, 26.6% corneal opacifications, 16.7% bilateral lens dislocation upwards, 6.7% optic nerve hypoplasia, 3.3% poor foveal development, and 3.3% Wilms tumor. CONCLUSIONS: Up to the age of 40 years, 15% of patients were diagnosed with glaucoma per age decade. Frequent bilateral glaucoma and similar bilateral height of intraocular pressure suggest a genetic glaucoma disposition with malformation at Schlemm canal, besides possible sequential anatomic changes in the chamber angle. Associated ocular abnormalities limit visual prognosis.

Common genetic variants associated with open-angle glaucoma.

Open-angle glaucoma (glaucoma) is a major eye disorder characterized by optic disc pathology. Recent genome-wide association studies identified new loci associated with clinically relevant optic disc parameters, such as the optic disc area and vertical cup-disc ratio (VCDR). We examined to what extent these loci are involved in glaucoma. The loci studied include ATOH7, CDC7/TGFBR3 and SALL1 for optic disc area, and CDKN2B, SIX1, SCYL1/LTBP3, CHEK2, ATOH7 and DCLK1 for VCDR. We performed a meta-analysis using data from six independent studies including: the Rotterdam Study (n= 5736), Genetic Research in Isolated Populations combined with Erasmus Rucphen Family study (n= 1750), Amsterdam Glaucoma Study (n= 296) and cohorts from Erlangen and Tübingen (n= 1363), Southampton (n= 702) and deCODE (n= 36 151) resulting in a total of 3161 glaucoma cases and 42 837 controls. Of the eight loci, we found significant evidence (P= 1.41 × 10(-8)) for the association of CDKN2B with glaucoma [odds ratio (OR) for those homozygous for the risk allele: 0.76; 95% confidence interval (CI): 0.70-0.84], for the role of ATOH7 (OR: 1.28; 95% CI: 1.12-1.47) and for SIX1 (OR: 1.20; 95% CI: 1.10-1.31) when adjusting for the number of tested loci. Furthermore, there was a borderline significant association of CDC7/TGFBR3 and SALL1 (both P= 0.04) with glaucoma. In conclusion, we found consistent evidence for three common variants (CDKN2B, ATOH7 and SIX1) significantly associated with glaucoma. These findings may shed new light on the pathophysiological protein pathways leading to glaucoma, and point to pathways involved in the growth and development of the optic nerve.

Evidence for RPGRIP1 gene as risk factor for primary open angle glaucoma.

Glaucoma is a genetically heterogeneous disorder and is the second cause of blindness worldwide owing to the progressive degeneration of retinal ganglion neurons. Very few genes causing glaucoma were identified to this date. In this study, we screened 10 candidate genes of glaucoma between the D14S261 and D14S121 markers of chromosome 14q11, a critical region previously linked to primary open-angle glaucoma (POAG). Mutation analyses of two large cohorts of patients with POAG, normal tension glaucoma (NTG) and juvenile open-angle glaucoma (JOAG), and control subjects, found only association of non-synonymous heterozygous variants of the retinitis pigmentosa GTPase regulator-interacting protein 1 (RPGRIP1) with POAG, NTG and JOAG. The 20 non-synonymous variants identified in RPGRIP1 were all distinct from variants causing photoreceptor dystrophies and were found throughout all but one domain (RPGR-interacting domain) of RPGRIP1. Among them, 14 missense variants clustered within or around the C2 domains of RPGRIP1. Yeast two-hybrid analyses of a subset of the missense mutations within the C2 domains of RPGRIP1 shows that five of them (p.R598Q, p.A635G, p.T806I, p.A837G and p.I838V) decrease the association of the C2 domains with nephrocystin-4 (NPHPH). When considering only these five confirmed C2-domain mutations, the association remains statistically significant (P=0.001). Altogether, the data support that heterozygous non-synonymous variants of RPGRIP1 may cause or increase the susceptibility to various forms of glaucoma and that among other factors, physical impairment of the interaction of RPGRIP1with different proteins may contribute to the pathogenesis of forms of glaucoma.

Genome-wide association study with DNA pooling identifies variants at CNTNAP2 associated with pseudoexfoliation syndrome.

Genetic and nongenetic factors contribute to development of pseudoexfoliation (PEX) syndrome, a complex, age-related, generalized matrix process frequently associated with glaucoma. To identify specific genetic variants underlying its etiology, we performed a genome-wide association study (GWAS) using a DNA-pooling approach. Therefore, equimolar amounts of DNA samples of 80 subjects with PEX syndrome, 80 with PEX glaucoma (PEXG) and 80 controls were combined into separate pools and hybridized to 500K SNP arrays (Affymetrix). Array probe intensity data were analyzed and visualized with expressly developed software tools GPFrontend and GPGraphics in combination with GenePool software. For replication, independent German cohorts of 610 unrelated patients with PEX/PEXG and 364 controls as well as Italian cohorts of 249 patients and 190 controls were used. Of 19, 17 SNPs showing significant allele frequency difference in DNA pools were confirmed by individual genotyping. Further single genotyping at CNTNAP2 locus revealed association between PEX/PEXG for two SNPs, which was confirmed in an independent German but not the Italian cohort. Both SNPs remained significant in the combined German cohorts even after Bonferroni correction (rs2107856: P(c)=0.0108, rs2141388: P(c)=0.0072). CNTNAP2 was found to be ubiquitously expressed in all human ocular tissues, particularly in retina, and localized to cell membranes of epithelial, endothelial, smooth muscle, glial and neuronal cells. Confirming efficiency of GWAS with DNA-pooling approach by detection of the known LOXL1 locus, our study data show evidence for association of CNTNAP2 with PEX syndrome and PEXG in German patients.

Apolipoprotein E genotypes in pseudoexfoliation syndrome and pseudoexfoliation glaucoma.

PURPOSE: Pseudoexfoliation (PEX) syndrome, an age-related, systemic, elastic microfibrillopathy, is characterized by fibrillar-granular deposits in the anterior segment of the eye. Although not representing a true amyloidosis, PEX syndrome shares some features with amyloid disorders, such as Alzheimer disease. It has been shown that amyloid-associated proteins also occur in association with PEX fibrils. Apolipoprotein E (Apo-E) is directly involved in these amyloid deposition and fibrils formation. The ε4 allele of APOE gene was shown to be associated both with an increased risk for coronary heart disease and late-onset Alzheimer disease. In this study, we therefore investigated whether APOE alleles are associated with PEX syndrome and/or PEX glaucoma (PEXG) in 2 large cohorts of German and Italian origin. METHODS: The 3 common APOE alleles ε2, ε3, and ε4 were genotyped in 661 unrelated patients (459 PEXG and 202 PEX patients) and 342 healthy individuals of German origin and furthermore in 209 unrelated patients (133 PEXG and 76 PEX patients) and 190 healthy individuals of Italian origin using TaqMan assays for allelic discrimination. A genetic association study was then performed. RESULTS: The ε3 allele was found to be the most common in both populations (80% to 83%), whereas the ε2 allele was the rarest (6% to 9%). No significant differences in allele and genotype frequencies between both groups were observed in either population. CONCLUSION: Our data show that APOE genotypes are not associated with PEX and PEXG in either Germans or Italians.

Dental and Craniofacial Anomalies Associated with Axenfeld-Rieger Syndrome with PITX2 Mutation.

Axenfeld-Rieger syndrome (ARS) (OMIM Nr.: 180500) is a rare autosomal dominant disorder (1 : 200000) with genetic and morphologic variability. Glaucoma is associated in 50% of the patients. Craniofacial and dental anomalies are frequently reported with ARS. The present study was designed as a multidisciplinary analysis of orthodontic, ophthalmologic, and genotypical features. A three-generation pedigree was ascertained through a family with ARS. Clinically, radiographic and genetic analyses were performed. Despite an identical genotype in all patients, the phenotype varies in expressivity of craniofacial and dental morphology. Screening for PITX2 and FOXC1 mutations by direct DNA-sequencing revealed a P64L missense mutation in PITX2 in all family members, supporting earlier reports that PITX2 is an essential factor in morphogenesis of teeth and craniofacial skeleton. Despite the fact that the family members had identical mutations, morphologic differences were evident. The concomitant occurrence of rare dental and craniofacial anomalies may be early diagnostic indications of ARS. Early detection of ARS and elevated intraocular pressure (IOP) helps to prevent visual field loss.

Mitochondrial haplogroup U is associated with a reduced risk to develop exfoliation glaucoma in the German population.

BACKGROUND: Various lines of evidence demonstrate the involvement of mitochondrial dysfunction in the pathogenesis of glaucoma. Therefore, mitochondrial DNA is a promising candidate for genetic susceptibility studies on glaucoma. To test the hypothesis that mitochondrial haplogroups influence the risk to develop glaucoma, we genotyped 12 single-nucleotide polymorphisms that define the European mitochondrial DNA haplogroups in healthy controls and two German patient cohorts with either exfoliation glaucoma or the normal tension subgroup of primary open angle glaucoma. RESULTS: Mitochondrial haplogroup U was significantly under-represented in patients with exfoliation glaucoma (8.3% compared with 18.9% in controls; p = 0.004). CONCLUSIONS: People with haplogroup U have a lower risk to develop exfoliation glaucoma. Our results substantiate the suggestion that mitochondrial alterations have an impact on the etiology of glaucoma.

Lysyl oxidase-like 1 gene polymorphisms in German patients with normal tension glaucoma, pigmentary glaucoma and exfoliation glaucoma.

PURPOSE: To evaluate the association between lysyl-oxidase-like 1 (LOXL1) gene polymorphisms and exfoliation glaucoma, pigmentary glaucoma and normal tension glaucoma in a case-control cohort of German patients. METHODS: Six single nucleotide polymorphisms in a 22 kb genomic region encompassing the LOXL1 gene plus an additional "outlier" single nucleotide polymorphism located approximately 1.1 Mb upstream of LOXL1 were genotyped in 128 exfoliation glaucoma patients, 88 pigmentary glaucoma patients, 273 normal tension glaucoma patients, and 280 healthy control subjects either with TaqMan allelic discrimination assays or by direct sequencing, and a genetic association study was performed. RESULTS: For the exfoliation glaucoma cases, case-control allelic association for 6 single nucleotide polymorphisms were highly significant. In contrast, there were no genotypic differences between pigmentary glaucoma cases, normal tension glaucoma cases and controls. However, an association between rs1048661 genotype and age at disease onset was suggested for pigmentary glaucoma patients. CONCLUSIONS: Our study reveals that in the German population the LOXL1 genetic predisposition is limited to exfoliation glaucoma and does not include normal tension glaucoma. In addition, our study implicates that LOXL1 polymorphisms are not likely to have a major influence on the pathophysiology of pigmentary glaucoma. However, 1 nonsynonymous polymorphism may serve as a predictor of age at disease onset in pigmentary glaucoma.

Open globe injuries induced by glass bottles containing carbonated drinks.

BACKGROUND: Reports on open globe injuries caused by exploding bottles containing carbonated drinks have already raised the demand to switch from multi-use glass bottles to plastic bottles. We retrospectively analyzed our files to find out whether this type of injury is limited to multi-use glass bottles, and to what extent carelessness contributed to the injury PATIENTS: Among 1,402 open globe injuries that were treated in the departments of ophthalmology at the universities of Freiburg and Würzburg between 1981 and 2004, we retrospectively identified 33 injuries caused by exploding bottles containing carbonated drinks. Patients were excluded from analysis when the destruction of the bottle was intended (destroyed with a hammer, or bottle used as a weapon). The circumstances of the injury, the treatment and the functional outcome was analyzed. RESULTS: 2.4% of all open globe injuries were related to exploding bottles, with a risk of one injury per 1 million inhabitants per year. Ten eyes suffered from a spontaneous explosion of the bottle when it was moved on a shelf or taken out of a box. Eighteen eyes received the injury after the bottle had fallen down and exploded (six of them in children 2 to 8 years). Five bottles exploded during opening of the bottle. In four cases, the bottle cap came off spontaneously and penetrated the eye. Eleven injuries (33%) occurred at work, five of them while moving the bottle and six during breaks at work. CONCLUSION: Spontaneous explosions in multi-use glass bottles could easily be avoided by changing to plastic bottles; however, exploding single-use glass bottles Containing sparkling wine also contributed to the injuries. In many cases, carelessness was involved. Glass bottles should be never exposed to heat or shaking, and children should never carry glass bottles containing carbonated drinks.

Evaluation of nine candidate genes in patients with normal tension glaucoma: a case control study.

BACKGROUND: Normal tension glaucoma is a major subtype of glaucoma, associated with intraocular pressures that are within the statistically normal range of the population. Monogenic forms following classical inheritance patterns are rare in this glaucoma subtype. Instead, multigenic inheritance is proposed for the majority of cases. The present study tested common sequence variants in candidate genes for association with normal tension glaucoma in the German population. METHODS: Ninety-eight SNPs were selected to tag the common genetic variation in nine genes, namely OPTN (optineurin), RDX (radixin), SNX16 (sorting nexin 16), OPA1 (optic atrophy 1), MFN1 (mitofusin 1), MFN2 (mitofusin 2), PARL (presenilin associated, rhomboid-like), SOD2 (superoxide dismutase 2, mitochondrial) and CYP1B1 (cytochrome P450, family 1, subfamily B, polypeptide 1). These SNPs were genotyped in 285 cases and 282 fully evaluated matched controls. Statistical analyses comprised single polymorphism association as well as haplogroup based association testing. RESULTS: Results suggested that genetic variation in five of the candidate genes (RDX, SNX16, OPA1, SOD2 and CYP1B1) is unlikely to confer major risk to develop normal tension glaucoma in the German population. In contrast, we observed a trend towards association of single SNPs in OPTN, MFN1, MFN2 and PARL. The SNPs of OPTN, MFN2 and PARL were further analysed by multimarker haplotype-based association testing. We identified a risk haplotype being more frequent in patients and a vice versa situation for the complementary protective haplotype in each of the three genes. CONCLUSION: Common variants of OPTN, PARL, MFN1 and MFN2 should be analysed in other cohorts to confirm their involvement in normal tension glaucoma.

Heterozygous NTF4 mutations impairing neurotrophin-4 signaling in patients with primary open-angle glaucoma.

Glaucoma, a main cause of blindness in the developed world, is characterized by progressive degeneration of retinal ganglion cells (RGCs), resulting in irreversible loss of vision. Although members of the neurotrophin gene family in various species are known to support the survival of numerous neuronal populations, including RGCs, it is less clear whether they are also required for survival and maintenance of adult neurons in humans. Here, we report seven different heterozygous mutations in the Neurotrophin-4 (NTF4) gene accounting for about 1.7% of primary open-angle glaucoma patients of European origin. Molecular modeling predicted a decreased affinity of neurotrophin 4 protein (NT-4) mutants with its specific tyrosine kinase receptor B (TrkB). Expression of recombinant NT-4 carrying the most frequent mutation was demonstrated to lead to decreased activation of TrkB. These findings suggest a pathway in the pathophysiology of glaucoma through loss of neurotrophic function and may eventually open the possibility of using ligands activating TrkB to prevent the progression of the disease.

A clinical and molecular genetic study of German patients with primary congenital glaucoma.

PURPOSE: To estimate an accurate incidence rate for CYP1B1 mutations in German patients with primary congenital glaucoma (PCG). DESIGN: Observational case series. METHODS: Blood was obtained from 39 unrelated patients of German origin with clear clinical features of PCG and screened for mutations in the CYP1B1 gene using direct deoxyribonucleic acid sequencing. One hundred ethnically matched control subjects were screened for novel sequence variants using restriction fragment length polymorphism and denaturing high-performance liquid chromatography. RESULTS: Sequence analysis identified 11 different mutations in 7 patients (18%). Four patients were compound heterozygotes, 2 subjects heterozygous, and 1 homozygous for CYP1B1 mutations. One deletion (c.199_206del8) and 3 missense mutations (L177P, F190L, and S282N) were novel. None of the novel missense mutations identified was found in normal controls. CONCLUSIONS: Our results indicate that only a minor proportion of German PCG patients harbor mutations in the CYP1B1 gene and are in line with similar studies from other ethnic populations in which the rate of consanguinity is low. In addition, this is the first report discussing the phenotypes of German PCG patients with and without CYP1B1 mutations.

Exploring functional candidate genes for genetic association in german patients with pseudoexfoliation syndrome and pseudoexfoliation glaucoma.

PURPOSE: Pseudoexfoliation (PEX) syndrome is a generalized elastic microfibrillopathy characterized by fibrillar deposits in intra- and extraocular tissues. Genetic and nongenetic factors are known to be involved in its etiopathogenesis. This study was focused on six functional candidate genes involved in PEX material deposition and the analysis of their potential association with PEX syndrome and PEX glaucoma (PEXG). METHODS: Fifty single-nucleotide polymorphisms (SNPs) capturing >95% of overall genetic variance observed in Europeans at loci for FBN1, LTBP2, MFAP2, TGM2, TGF-b1, and CLU were genotyped in 333 unrelated PEX-affected and 342 healthy individuals of German origin, and a genetic association study was performed. To replicate the findings, two SNPs of the CLU gene were genotyped in a further 328 unrelated German patients with PEX as well as in 209 Italian patients with PEX and 190 Italian control subjects. RESULTS: Association with PEX was observed only for the SNP rs2279590 in intron 8 of the CLU gene coding for clusterin (corrected P = 0.0347, OR = 1.34) in our first German cohort. Likewise, a frequent haplotype encompassing the associated risk allele showed nominally significant association. None of remaining SNPs or SNP haplotypes were associated with PEX. The association found was confirmed in a second German cohort (P = 0.0244) but not in the Italian cohort (P = 0.7173). In addition, the association with CLU SNP rs2279590 was more significant in German patients with PEX syndrome than in those with PEXG. CONCLUSIONS: Genetic variants in the gene encoding clusterin may represent a risk factor for PEX in German patients but not in Italian patients. Variants in FBN1, LTBP2, MFAP2, TGF-b1, and TGM2 do not play a major role in the etiology of PEX syndrome, at least in German patients.