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Biomedical subjects

Janey L Wiggs

Publications and source records attributed to Janey L Wiggs.

11 recordsLinked to original sources

Can we identify people with Alzheimer's disease from examination of the eye? A bidirectional Mendelian randomization (MR) study.

BACKGROUND: Neurodegeneration in Alzheimer's disease (AD) is thought to be driven by amyloid-beta and tau deposition in the cerebral vasculature and brain. As the eye is an extension of the central nervous system, this study aimed to determine which neurovascular and neuroretinal changes in the eye are caused by AD rather than associations of the disease. METHODS: Bidirectional two-sample univariable and multivariable Mendelian randomization (MR) methods were applied. Instrumental variables were derived from genome-wide association studies (GWAS) of AD and the following ocular features: thickness measurements of central macula (MT), retinal nerve fibre layer (mRNFL), ganglion cell-inner plexiform layer (mGCIPL), outer nuclear layer (ONL), inner segment layer (IS), and outer segment (OS) from macular region OCT scans; arteriolar tortuosity (AT), venular tortuosity (VT), venular width (VW), fractal dimension (FD), vertical cup-to-disc ratio (VCDR), optic cup area (OCA), and optic disc area (ODA) derived from other imaging methods. RESULTS: There was strong evidence that genetic liability to AD affected the retinal vasculature by specifically increasing AT (β = 0.007;95%CI=0.002,0.011;p-value=0.005) in UK Biobank participants (n=52,798). AD may influence the mRNFL (β=-0.047,95%CI=-0.119,0.023,p-value=0.18) and mGCIPL (β=-0.061;95%CI=-0.14,0.025,p-value=0.16) of the inner retina and OS layer (β = 0.044;95%CI=-0.0001,0.08;p-value=0.05) but the evidence was weak. Multivariable MR analysis showed that a causal relationship between optic disc area and AD (OR=0.76;95%CI=0.62,0.93,p-value=0.009) was probably mediated by refractive error. CONCLUSION: Early cerebrovascular signs of AD may be detected by examination of the eye. Further investigation is required to determine the clinical utility of eye screening for dementia.

Humans↗

Association of FOXC1 Duplications With Juvenile Open-Angle Glaucoma.

IMPORTANCE: While FOXC1 single-nucleotide variants and deletions are well-established causes of Axenfeld-Rieger syndrome, few FOXC1 duplications have been reported. This study investigated families with duplications encompassing the FOXC1 gene to refine the associated phenotypic spectrum and contribution to glaucoma. OBJECTIVE: To investigate the prevalence and phenotype of FOXC1 duplications in 2 large glaucoma registries. DESIGN, SETTING, AND PARTICIPANTS: This retrospective observational genetic cohort study included participants recruited from the Australian & New Zealand Registry of Advanced Glaucoma (ANZRAG) and the Massachusetts Eye and Ear (MEE) cohort from 2008 through 2025. Participants with glaucoma, and available relatives, underwent genomic testing to identify duplications encompassing FOXC1 using exome sequencing and genotyping arrays (ANZRAG) or whole-genome sequencing (MEE). Data analyses were conducted from 2022 through 2025. MAIN OUTCOMES AND MEASURES: Prevalence of FOXC1 duplications, age at glaucoma onset, and phenotype, including ocular and systemic features. RESULTS: Twenty individuals from 10 families (50% female and 50% male; 70% self-described as broadly European [Australian/British, British, English/German, English/Polish, European, or Scottish], 25% as Asian [Chinese or Filipino], and 5% as Latin American [Salvadoran]) were identified with FOXC1 duplications. All genetically tested individuals were diagnosed with glaucoma, demonstrating high penetrance. Seventeen individuals were referred with juvenile open-angle glaucoma (JOAG), 1 with primary open-angle glaucoma, 1 with primary congenital glaucoma, and 1 with anterior segment dysgenesis. The diagnosis of 4 individuals from 1 family with ectropion uveae was revised to anterior segment dysgenesis. Systemic features were reported for 2 participants (10.5%), including subtle dental findings and mild facial dysmorphism. Duplications encompassing FOXC1 were among the most common monogenic contributors to JOAG. In the ANZRAG group, they accounted for 13.5% (95% CI, 6.7%-25.3%) of JOAG probands with a genetic diagnosis, second to MYOC (53.8%; 95% CI, 40.5%-66.7%). In the MEE group, FOXC1 duplications accounted for 9.5% (95% CI, 2.7%-28.9%) of JOAG probands with a genetic diagnosis. CONCLUSIONS AND RELEVANCE: These findings suggest FOXC1 duplications are an underrecognized, highly penetrant, but variably expressive, genetic variation associated with JOAG. Findings for the relatively modest number of individuals in the retrospective study were associated with wide confidence intervals. This limitation is often inherent to studies of JOAG, a rare condition for which individual genetic variants account for only a subset of cases. Despite this, the findings highlight the genetic heterogeneity of JOAG and support the potential importance of considering routine genetic copy-number variant analysis for individuals with JOAG.

Humans↗

Genetic etiologies of glaucoma.

Glaucoma can be inherited as a mendelian autosomal-dominant or autosomal-recessive trait, or as a complex multifactorial trait. Genetic approaches have helped define the underlying molecular events responsible for some mendelian forms of the disease and have identified the chromosome locations of genes that are likely to contribute to common complex forms. Future directions include the discovery of new glaucoma genes, determining the clinical phenotypes associated with specific genes and mutations, investigating environmental factors that may contribute to the disease, investigating gene-environment interactions and gene-gene interactions, and developing a mutation database that can be used for diagnostic and prognostic testing.

Genes, Dominant↗

Distribution of optineurin sequence variations in an ethnically diverse population of low-tension glaucoma patients from the United States.

PURPOSE: Previous studies have suggested that Optineurin (OPTN) sequence variants contribute to low-tension glaucoma (LTG) in ethnically homogeneous populations. The purpose of this study is to evaluate the prevalence of OPTN sequence variants in an ethnically diverse population of LTG patients from the United States, and to describe the phenotype of patients with OPTN sequence variants preferentially found in LTG patients. METHODS: Genomic DNA purified from 67 LTG patients was screened for DNA sequence variants located in the exons and flanking introns of the OPTN gene using high-performance liquid chromatography analysis and direct genomic DNA sequencing. Eighty-six primary open-angle glaucoma probands and 100 control patients were also analyzed. RESULTS: Nine OPTN DNA sequence variants were identified in this patient population including the 2 previously identified heterozygous nonsynonymous single-nucleotide polymorphisms in exons 4 and 5. Four LTG patients with severe disease and positive family history of glaucoma, were found to have DNA sequence changes not found in primary open-angle glaucoma probands or control individuals including the previously reported E50K variation. CONCLUSIONS: The results of this study support the rare association of OPTN sequence variants with familial forms of LTG. The E50K mutation seems to be associated with a severe form of LTG, and although rare, the identification of this sequence variant in patients at risk may help direct appropriate therapy.

Adult↗

Distribution of WDR36 DNA sequence variants in patients with primary open-angle glaucoma.

PURPOSE: To determine the distribution of WDR36 sequence variants in a cohort of patients with primary open-angle glaucoma (POAG) in the United States. METHODS: All of the 23 coding exons and flanking introns of the WDR36 gene were sequenced in 118 probands from families with at least two members affected by POAG, 6 probands from juvenile-onset POAG families, and 108 control individuals. RESULTS: Thirty-two WDR36 sequence variants were found in this population of patients with POAG. Nonsynonymous single-nucleotide polymorphisms (SNPs), including those previously described as "disease-causing" and "disease susceptibility," were found in 17% of POAG patients and 4% of control subjects. Although the distribution of WDR36 variants in the pedigrees did not show consistent segregation with the disease, the WDR36 sequence variants were found more frequently in patients with more severe disease. CONCLUSIONS: The results of this study suggest that abnormalities in WDR36 alone are not sufficient to cause POAG. The association of WDR36 sequence variants with more severe disease in affected individuals suggests that defects in the WDR36 gene can contribute to POAG and that WDR36 may be a glaucoma modifier gene.

Adult↗

Genes associated with human glaucoma.

Glaucoma is a common blinding disease worldwide. Most forms of the disease are inherited in some way. The identification of genes responsible for glaucoma will lead to insights into the underlying biochemical defects as well as provide the basis for new methods of diagnosis and therapy. Glaucoma patients who are identified early and treated appropriately have the best chance of maintaining useful sight.

Glaucoma, Open-Angle↗

Early adult-onset POAG linked to 15q11-13 using ordered subset analysis.

PURPOSE: Primary open-angle glaucoma (POAG) is a complex inherited disorder. It has been demonstrated in other complex disorders that phenotypic heterogeneity may be the result of genetic heterogeneity and that stratification analysis can be used to increase the power of detection. Ordered subset analysis (OSA) is a recently described method that utilizes the variability of phenotypic traits to determine underlying genetic heterogeneity. METHODS: Eighty-six multiplex families with POAG were clinically ascertained for genetic analysis. Age at diagnosis (AAD) was used as a surrogate for age of onset in affected family members. Nine genetic markers within the 15q11-13 interval on chromosome 15 were used for OSA analysis. RESULTS: An 11-cM linkage interval with a peak LOD score of 3.24 centered at the GABRB3 locus (P = 0.013 by permutation test) was identified in a subset of 15 families, which represents 17% of the total dataset (15/86 families). The mean AAD for the affected OSA families was 44.1 +/- 9.1 years (SD). The mean AAD for the complementary group was 61.3 +/- 10.4 years. African-American and white families were well represented in the OSA subset. CONCLUSIONS: Linkage was identified for POAG to an 11-cM region on chromosome 15, designated GLC1I. This result provides further evidence that AAD and other phenotypic traits can be used as stratification variables to identify genes in complex disorders such as POAG and suggests that the 15q11-13 locus is one of the largest genetic contributors to POAG identified to date.

Adult↗

Lack of association of mutations in optineurin with disease in patients with adult-onset primary open-angle glaucoma.

OBJECTIVE: To determine whether mutations in the optineurin gene contribute to susceptibility to adult-onset primary open-angle glaucoma. METHODS: The optineurin gene was screened in 86 probands with adult-onset primary open-angle glaucoma and in 80 age-matched control subjects. Exons 4 and 5, containing the recurrent mutations identified in patients with normal-tension glaucoma, were sequenced in all individuals studied, while the remaining exons were screened for DNA sequence variants with denaturing high-performance liquid chromatography. RESULTS: The recurrent mutation, Met98Lys, previously found to be associated with an increased risk of disease was found in 8 (9%) of 86 probands. We also found the Met98Lys mutation in 10% of individuals from a control population of similar age, sex, and ethnicity. Consistent segregation of the mutation with the disease was not demonstrated in any of the 8 families. No other DNA changes altering the amino acid structure of the protein were found. CONCLUSION: The mutations in the optineurin gene associated with normal-tension glaucoma are not associated with adult-onset primary open-angle glaucoma in this patient population. Clinical Relevance Genetic abnormalities that render the optic nerve susceptible to degeneration are excellent candidates for genetic factors that could contribute to adult-onset primary open-angle glaucoma. Mutations in optineurin have been associated with normal-tension glaucoma, but are not associated with disease in patients with adult-onset primary open-angle glaucoma. This result may indicate that normal-tension glaucoma is not necessarily part of the phenotypic spectrum of adult open-angle glaucoma.

Aged↗

DNA sequence variants in the tyrosinase-related protein 1 (TYRP1) gene are not associated with human pigmentary glaucoma.

PURPOSE: Pigmentary glaucoma is a common form of glaucoma affecting young adults. Previous studies have suggested that multiple factors, including multiple genetic factors, may be responsible for this condition. Recently, a form of glaucoma associated with pigment dispersion and iris atrophy was identified in the DBA/2J mouse. Abnormalities in the mouse Tyrp1 gene contribute to this condition. The purpose of this study was to determine if DNA sequence variants in the human TYRP1 gene are associated with pigmentary glaucoma in humans. METHODS: The protein coding regions and intron/exon boundaries of the human TYRP1 gene were sequenced using genomic DNA samples from probands from pedigrees affected by pigment dispersion syndrome and pigmentary glaucoma. RESULTS: Three novel synonymous single nucleotide polymorphisms (SNPs) were found in two affected individuals. However, these polymorphisms did not define a haplotype that segregated with the disease in the families. DNA sequence variants that altered the amino acid sequence of TYRP1 were not found. CONCLUSIONS: Despite the phenotypic similarity between the glaucoma in the DBA/2J mouse and human pigmentary glaucoma, the results of this study suggest that DNA sequence variants in the human TYRP1 gene are not associated with inherited pigmentary glaucoma in humans.

DNA↗

Mutations in genes encoding melanosomal proteins cause pigmentary glaucoma in DBA/2J mice.

Pigmentary glaucoma is a significant cause of human blindness. Abnormally liberated iris pigment and cell debris enter the ocular drainage structures, leading to increased intraocular pressure (IOP) and glaucoma. DBA/2J (D2) mice develop a form of pigmentary glaucoma involving iris pigment dispersion (IPD) and iris stromal atrophy (ISA). Using high-resolution mapping techniques, sequencing and functional genetic tests, we show that IPD and ISA result from mutations in related genes encoding melanosomal proteins. IPD is caused by a premature stop codon mutation in the Gpnmb (GpnmbR150X) gene, as proved by the occurrence of IPD only in D2 mice that are homozygous with respect to GpnmbR150X; otherwise, similar D2 mice that are not homozygous for GpnmbR150X do not develop IPD. ISA is caused by the recessive Tyrp1b mutant allele and rescued by the transgenic introduction of wildtype Tyrp1. We hypothesize that IPD and ISA alter melanosomes, allowing toxic intermediates of pigment production to leak from melanosomes, causing iris disease and subsequent pigmentary glaucoma. This is supported by the rescue of IPD and ISA in D2 eyes with substantially decreased pigment production. These data indicate that pigment production and mutant melanosomal protein genes may contribute to human pigmentary glaucoma. The fact that hypopigmentation profoundly alleviates the D2 disease indicates that therapeutic strategies designed to decrease pigment production may be beneficial in human pigmentary glaucoma.

Animals↗