Ophthalmic Manifestations of ROSAH (Retinal Dystrophy, Optic Nerve Edema, Splenomegaly, Anhidrosis, and Headache) Syndrome, an Inherited NF κB-Mediated Autoinflammatory Disease with Retinal Dystrophy.

PURPOSE: We aimed to characterize the ocular phenotype of patients with ROSAH (retinal dystrophy, optic nerve edema, splenomegaly, anhidrosis, and headache) syndrome and their response to therapy. DESIGN: Single-center observational case study. PARTICIPANTS: Eleven patients with a diagnosis of ROSAH syndrome and mutation in ALPK1 were included. METHODS: Patients with molecularly confirmed ROSAH syndrome underwent ophthalmic evaluation, including visual acuity testing, slit-lamp and dilated examinations, color fundus and autofluorescence imaging, fluorescein angiography, OCT, and electrophysiologic testing. MAIN OUTCOME MEASURES: Visual acuity, electrophysiology, fluorescein angiography, and OCT findings. RESULTS: Eleven individuals (6 female and 5 male patients) from 7 families ranging in age from 7.3 to 60.2 years at the time of the initial evaluation were included in this study. Seven patients were followed up for a mean of 2.6 years (range, 0.33-5.0 years). Best-corrected visual acuity at baseline ranged from 20/16 to no light perception. Variable signs or sequelae of intraocular inflammation were observed in 9 patients, including keratic precipitates, band keratopathy, trace to 2+ anterior chamber cells, cystoid macular edema, and retinal vasculitis on fluorescein angiography. Ten patients were observed to show optic disc elevation and demonstrated peripapillary thickening on OCT. Seven patients showed retinal degeneration consistent with a cone-rod dystrophy, with atrophy tending to involve the posterior pole and extending peripherally. One patient with normal electroretinography findings and visual evoked potential was found to have decreased Arden ratio on electro-oculography. CONCLUSIONS: Leveraging insights from the largest single-center ROSAH cohort described to date, this study identified 3 main factors as contributing to changes in visual function of patients with ROSAH syndrome: optic nerve involvement; intraocular inflammation, including cystoid macular edema; and retinal degeneration. More work is needed to determine how to arrest the progressive vision loss associated with ROSAH syndrome. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

ALPK1 missense pathogenic variant in five families leads to ROSAH syndrome, an ocular multisystem autosomal dominant disorder.

PURPOSE: To identify the molecular cause in five unrelated families with a distinct autosomal dominant ocular systemic disorder we called ROSAH syndrome due to clinical features of retinal dystrophy, optic nerve edema, splenomegaly, anhidrosis, and migraine headache. METHODS: Independent discovery exome and genome sequencing in families 1, 2, and 3, and confirmation in families 4 and 5. Expression of wild-type messenger RNA and protein in human and mouse tissues and cell lines. Ciliary assays in fibroblasts from affected and unaffected family members. RESULTS: We found the heterozygous missense variant in the ɑ-kinase gene, ALPK1, (c.710C>T, [p.Thr237Met]), segregated with disease in all five families. All patients shared the ROSAH phenotype with additional low-grade ocular inflammation, pancytopenia, recurrent infections, and mild renal impairment in some. ALPK1 was notably expressed in retina, retinal pigment epithelium, and optic nerve, with immunofluorescence indicating localization to the basal body of the connecting cilium of the photoreceptors, and presence in the sweat glands. Immunocytofluorescence revealed expression at the centrioles and spindle poles during metaphase, and at the base of the primary cilium. Affected family member fibroblasts demonstrated defective ciliogenesis. CONCLUSION: Heterozygosity for ALPK1, p.Thr237Met leads to ROSAH syndrome, an autosomal dominant ocular systemic disorder.

Clinical characteristics and aetiology of uveitis in a viral haemorrhagic fever zone.

BACKGROUND/OBJECTIVES: Studies on uveitis in Sierra Leone were conducted prior to the Ebola Virus Disease epidemic of 2013-16, which was associated with uveitis in 20% of survivors. They did not include imaging or investigation of tuberculosis and used laboratory services outside the country. We performed a cross-sectional study on patients presenting with uveitis to establish their clinical characteristics and identify the impact of in-country laboratory diagnoses. METHODS: We invited uveitis cases presenting to Eye Clinics in Sierra Leone from March to September 2022 to participate in the study. They underwent a diagnostic work-up, including fundus and ocular coherence tomography imaging. Active uveitis cases underwent further investigations including serology and immunological tests for syphilis, tuberculosis, herpetic viruses and HIV and chest radiographs. RESULTS: We recruited 128 patients. The median age was 34 (IQR 19) years and there was an equal gender split. Panuveitis was the predominant anatomical uveitis type (n = 51, 40%), followed by posterior uveitis (n = 36, 28%). Bilateral disease affected 40 patients (31%). Active uveitis was identified in 75 (59%) cases. ICD 11 definition of blindness with VA < 3/60 occurred in 55 (33%) uveitis eyes. Aetiology of uveitis from clinical and laboratory assessment demonstrated that most cases were of undifferentiated aetiology (n = 66, 52%), followed by toxoplasmosis (n = 46, 36%). Trauma contributed to eight (6%) cases, syphilis to 5 (4%) cases and Ebola to 2 (2%). CONCLUSIONS: Uveitis was associated with high levels of visual impairment. Posterior and panuveitis contributed to the highest proportion of uveitis cases. Laboratory studies helped differentiate syphilis as a significant aetiology of uveitis.

Childhood vision impairment and blindness in West Africa: public health measures and implications for systemic health.

Childhood blindness is an issue of global health impact, affecting approximately 2 million children worldwide. Vision 2020 and the United Nations Sustainable Development Goals previously identified childhood blindness as a key issue in the twentieth century, and while public health measures are underway, the precise etiologies and management require ongoing investigation and care, particularly within resource-limited settings such as sub-Saharan Africa. We systematically reviewed the literature on childhood blindness in West Africa to identify the anatomic classification and etiologies, particularly those causes of childhood blindness with systemic health implications. Treatable causes included cataract, refractive error, and corneal disease. Systemic etiologies identified included measles, rubella, vitamin A deficiency, and Ebola virus disease. While prior public health measures including vitamin A supplementation and vaccination programs have been deployed in most countries with reported data, multiple studies reported preventable or reversible etiologies of blindness and vision impairment. Ongoing research is necessary to standardize reporting for anatomies and/or etiologies of childhood blindness to determine the necessity of further development and implementation of public health measures that would ameliorate childhood blindness and vision impairment.

Clinical Characteristics and Aetiology of Uveitis in a Viral Haemorrhagic Fever Zone.

Background/Objectives: Studies on uveitis in Sierra Leone were conducted prior to the Ebola Virus Disease epidemic of 2013-16, which was associated with uveitis in 20% of survivors. They did not include imaging or investigation of tuberculosis and used laboratory services outside the country. We performed a cross-sectional study on patients presenting with uveitis to establish their clinical characteristics and identify the impact of in-country laboratory diagnoses. Methods: We invited uveitis cases presenting to Eye Clinics in Sierra Leone from March to September 2022 to participate in the study. They underwent a diagnostic work-up, including fundus and ocular coherence tomography imaging. Active uveitis cases underwent further investigations including serology and immunological tests for syphilis, tuberculosis and herpetic viruses and HIV, and chest radiographs. Results: We recruited 128 patients. The mean age was 36 ± 14 years and there was an equal gender split. Panuveitis was the predominant anatomical uveitis type (n=51, 40%), followed by posterior uveitis (n=36, 28%). Bilateral disease affected 40 patients (31%). Active uveitis was identified in 75 (59%) cases. ICD 11 definition of blindness with VA<3/60 occurred in 55 (33%) uveitis eyes. Aetiology of uveitis from clinical and laboratory assessment demonstrated that most cases were of undifferentiated aetiology (n=66, 52%), followed by toxoplasmosis (n=46, 36%). Trauma contributed to eight (6%) cases, syphilis to 5 (4%) cases and Ebola to 2 (2%). Conclusions: Uveitis was associated with high levels of visual impairment. Posterior and panuveitis contributed to the highest proportion of uveitis cases. Laboratory studies helped differentiate syphilis as a significant aetiology of uveitis.

An inherited disorder with splenomegaly, cytopenias, and vision loss.

We describe a novel inherited disorder consisting of idiopathic massive splenomegaly, cytopenias, anhidrosis, chronic optic nerve edema, and vision loss. This disorder involves three affected patients in a single non-consanguineous Caucasian family, a mother and two daughters, who are half-sisters. All three patients have had splenectomies; histopathology revealed congestion of the red pulp, but otherwise no abnormalities. Electron microscopic studies of splenic tissue showed no evidence for a storage disorder or other ultrastructural abnormality. Two of the three patients had bone marrow examinations that were non-diagnostic. All three patients developed progressive vision loss such that the two oldest patients are now blind, possibly due to a cone-rod dystrophy. Characteristics of vision loss in this family include early chronic optic nerve edema, and progressive vision loss, particularly central and color vision. Despite numerous medical and ophthalmic evaluations, no diagnosis has been discovered.

Endoscopic-assisted removal of intraocular foreign body embedded in ciliary sulcus.

Purpose: To report a novel approach for removal of intraocular foreign body in the ciliary sulcus. Observations: A 72-year-old male presented with an intraocular foreign body embedded in the ciliary body, localized with ultrasound biomicroscopy. An intraoperative endoscopic camera was then used to directly visualize the foreign body in the ciliary body and the object was successfully removed with intraocular forceps. Conclusions and Importance: Removal of foreign bodies in the ciliary sulcus often require either a transscleral approach or a pars plana approach with vitrectomy. In this case, direct visualization with endoscopy allowed for a much safer and less invasive technique for intraocular foreign body removal, preventing the need for sclerotomy or vitrectomy.

Ophthalmic sequelae and psychosocial impact in pediatric ebola survivors.

Background: Ebola virus disease (EVD) outbreaks in West Africa (2013-2016) and the Democratic Republic of Congo (2018-2020) have resulted in thousands of EVD survivors who remain at-risk for survivor sequelae. While EVD survivorship has been broadly reported in adult populations, pediatric EVD survivors are under-represented. In this cross-sectional study, we investigated the prevalence of eye disease, health-related quality-of-life, vision-related quality-of-life, and the burden of mental illness among pediatric EVD survivors in Sierra Leone. Methods: Twenty-three pediatric EVD survivors and 58 EVD close contacts were enrolled. Participants underwent a comprehensive ophthalmic examination and completed the following surveys: Pediatric Quality of Life Inventory Version 4.0, Effect of Youngsters Eyesight on Quality-of-Life, and the Revised Child Anxiety and Depression Scale. Findings: A higher prevalence of uveitis was observed in EVD survivor eyes (10·8%) cohort compared to close contacts eyes (1·7%, p=0·03). Overall, 47·8% of EVD survivor eyes and 31·9% of close contact eyes presented with an eye disease at the time of our study (p=0·25). Individuals diagnosed with an ocular complication had poorer vision-related quality-of-life (p=0·02). Interpretation: Both health related quality-of-life and vision-related quality-of-life were poor among EVD survivors and close contacts. The high prevalence of eye disease associated with reduced vision health, suggests that cross-disciplinary approaches are needed to address the unmet needs of EVD survivors. Funding: National Institutes of Health R01 EY029594, K23 EY030158; National Eye Institute; Research to Prevent Blindness (Emory Eye Center); Marcus Foundation Combating Childhood Illness; Emory Global Health Institute; Stanley M. Truhlsen Family Foundation.

Solid-state, dye-labeled DNA detects volatile compounds in the vapor phase.

This paper demonstrates a previously unreported property of deoxyribonucleic acid-the ability of dye-labeled, solid-state DNA dried onto a surface to detect odors delivered in the vapor phase by changes in fluorescence. This property is useful for engineering systems to detect volatiles and provides a way for artificial sensors to emulate the way cross-reactive olfactory receptors respond to and encode single odorous compounds and mixtures. Recent studies show that the vertebrate olfactory receptor repertoire arises from an unusually large gene family and that the receptor types that have been tested so far show variable breadths of response. In designing biomimetic artificial noses, the challenge has been to generate a similarly large sensor repertoire that can be manufactured with exact chemical precision and reproducibility and that has the requisite combinatorial complexity to detect odors in the real world. Here we describe an approach for generating and screening large, diverse libraries of defined sensors using single-stranded, fluorescent dye-labeled DNA that has been dried onto a substrate and pulsed with brief exposures to different odors. These new solid-state DNA-based sensors are sensitive and show differential, sequence-dependent responses. Furthermore, we show that large DNA-based sensor libraries can be rapidly screened for odor response diversity using standard high-throughput microarray methods. These observations describe new properties of DNA and provide a generalized approach for producing explicitly tailored sensor arrays that can be rationally chosen for the detection of target volatiles with different chemical structures that include biologically derived odors, toxic chemicals, and explosives.

Pseudoexfoliation and Cataract Syndrome Associated with Genetic and Epidemiological Factors in a Mayan Cohort of Guatemala.

The Mayan population of Guatemala is understudied within eye and vision research. Studying an observational homogenous, geographically isolated population of individuals seeking eye care may identify unique clinical, demographic, environmental and genetic risk factors for blinding eye disease that can inform targeted and effective screening strategies to achieve better and improved health care distribution. This study served to: (a) identify the ocular health needs within this population; and (b) identify any possible modifiable risk factors contributing to disease pathophysiology within this population. We conducted a cross-sectional study with 126 participants. Each participant completed a comprehensive eye examination, provided a blood sample for genetic analysis, and received a structured core baseline interview for a standardized epidemiological questionnaire at the Salama Lions Club Eye Hospital in Salama, Guatemala. Interpreters were available for translation to the patients' native dialect, to assist participants during their visit. We performed a genome-wide association study for ocular disease association on the blood samples using Illumina's HumanOmni2.5-8 chip to examine single nucleotide polymorphism SNPs in this population. After implementing quality control measures, we performed adjusted logistic regression analysis to determine which genetic and epidemiological factors were associated with eye disease. We found that the most prevalent eye conditions were cataracts (54.8%) followed by pseudoexfoliation syndrome (PXF) (24.6%). The population with both conditions was 22.2%. In our epidemiological analysis, we found that eye disease was significantly associated with advanced age. Cataracts were significantly more common among those living in the 10 districts with the least resources. Furthermore, having cataracts was associated with a greater likelihood of PXF after adjusting for both age and sex. In our genetic analysis, the SNP most nominally significantly associated with PXF lay within the gene KSR2 (p < 1 × 10-5). Several SNPs were associated with cataracts at genome-wide significance after adjusting for covariates (p < 5 × 10-8). About seventy five percent of the 33 cataract-associated SNPs lie within 13 genes, with the majority of genes having only one significant SNP (5 × 10-8). Using bioinformatic tools including PhenGenI, the Ensembl genome browser and literature review, these SNPs and genes have not previously been associated with PXF or cataracts, separately or in combination. This study can aid in understanding the prevalence of eye conditions in this population to better help inform public health planning and the delivery of quality, accessible, and relevant health and preventative care within Salama, Guatemala.

Intense Simulation-Based Surgical Education for Manual Small-Incision Cataract Surgery: The Ophthalmic Learning and Improvement Initiative in Cataract Surgery Randomized Clinical Trial in Kenya, Tanzania, Uganda, and Zimbabwe.

Importance: Cataracts account for 40% of cases of blindness globally, with surgery the only treatment. Objective: To determine whether adding simulation-based cataract surgical training to conventional training results in improved acquisition of surgical skills among trainees. Design, Setting, and Participants: A multicenter, investigator-masked, parallel-group, randomized clinical educational-intervention trial was conducted at 5 university hospital training institutions in Kenya, Tanzania, Uganda, and Zimbabwe from October 1, 2017, to September 30, 2019, with a follow-up of 15 months. Fifty-two trainee ophthalmologists were assessed for eligibility (required no prior cataract surgery as primary surgeon); 50 were recruited and randomized. Those assessing outcomes of surgical competency were masked to group assignment. Analysis was performed on an intention-to-treat basis. Interventions: The intervention group received a 5-day simulation-based cataract surgical training course, in addition to standard surgical training. The control group received standard training only, without a placebo intervention; however, those in the control group received the intervention training after the initial 12-month follow-up period. Main Outcomes and Measures: The primary outcome measure was overall surgical competency at 3 months, which was assessed with a validated competency assessment rubric. Secondary outcomes included surgical competence at 1 year and quantity and outcomes (including visual acuity and posterior capsule rupture) of cataract surgical procedures performed during a 1-year period. Results: Among the 50 participants (26 women [52.0%]; mean [SD] age, 32.3 [4.6] years), 25 were randomized to the intervention group, and 25 were randomized to the control group, with 1 dropout. Forty-nine participants were included in the final intention-to-treat analysis. Baseline characteristics were balanced. The participants in the intervention group had higher scores at 3 months compared with the participants in the control group, after adjusting for baseline assessment rubric score. The participants in the intervention group were estimated to have scores 16.6 points (out of 40) higher (95% CI, 14.4-18.7; P < .001) at 3 months than the participants in the control group. The participants in the intervention group performed a mean of 21.5 cataract surgical procedures in the year after the training, while the participants in the control group performed a mean of 8.5 cataract surgical procedures (mean difference, 13.0; 95% CI, 3.9-22.2; P < .001). Posterior capsule rupture rates (an important complication) were 7.8% (42 of 537) for the intervention group and 26.6% (54 of 203) for the control group (difference, 18.8%; 95% CI, 12.3%-25.3%; P < .001). Conclusions and Relevance: This randomized clinical trial provides evidence that intense simulation-based cataract surgical education facilitates the rapid acquisition of surgical competence and maximizes patient safety. Trial Registration: Pan-African Clinical Trial Registry, number PACTR201803002159198.

Impact and Trends in Global Ophthalmology.

Purpose of Review: Our goal is to provide a review of the impact, global estimates, and projection of vision impairment as well as ongoing systems for eye care delivery. Recent Findings: Many of the blinding diseases in developing countries are preventable or curable, but the lack of ophthalmologists, the lack of education, and the lack of access to any eye care are some of the major obstacles encountered. Summary: As our world becomes more interconnected through globalization, the interactions between different cultures and populations increase. Global ophthalmology is a field dedicated to building sustainable eye care delivery systems to deliver high-quality care in minimal resource settings, with the aim of reducing blindness around the world.

Correlation of visual outcome and patient satisfaction with preoperative keratometry after hyperopic laser in situ keratomileusis.

PURPOSE: To prospectively study the dependence of visual outcomes and patient satisfaction on corneal keratometry (K) in hyperopic laser in situ keratomileusis (LASIK). SETTING: John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, USA. METHODS: Twenty-six patients (49 eyes) who had hyperopic LASIK from January to October 2005 were prospectively studied. Twelve patients (24 eyes) with a preoperative K value less than 43.0 diopters (D) (Group 1) were compared with 14 patients (25 eyes) with a preoperative K value greater than 44.0 D (Group 2). RESULTS: The mean preoperative hyperopia was +3.44 D (range +1.57 to +5.25 D). Ten patients in Group 2 and 1 patient in Group 1 lost 2 or more lines of best spectacle-corrected visual acuity (BSCVA). There was a statistically significant difference in subjective patient satisfaction (scale 1 to 4; 4=most satisfied) between Group 1 and Group 2 (mean 2.75+/-0.61 and 1.52+/-0.66, respectively) (P<.0001). Group 2 had a statistically significantly higher dryness score (scale 0 to 3; 3=severe) (mean 1.84+/-0.70 versus 0.17+/-0.38) (P<.0001). There was no between-group difference in the degree of preoperative hyperopia or keratometric change. CONCLUSIONS: An increased incidence of loss of BSCVA and decreased patient satisfaction was associated with a preoperative K value greater than 44.0 D in hyperopic LASIK, indicating caution is required when performing LASIK in eyes with moderate to high hyperopia and steep preoperative corneal keratometry.

Minifragment screw fixation of the Scarf osteotomy.

BACKGROUND: Various techniques have been used for internal fixation of Scarf osteotomies. Stability of fixation plays an important role in determining the outcome. We prospectively studied 23 consecutive cases of hallux valgus treated with a scarf osteotomy, which were internally fixed with AO mini fragment screws. The aim of our study was to evaluate the clinical efficacy of the AO mini fragment screw used as fixation device in Scarf osteotomy. MATERIALS AND METHODS: Twenty-three feet (1 male, 16 female) were evaluated. Bilateral procedures were performed on six patients. Mean age was 46 years. The mean followup was 18 months. One surgeon performed all the procedures. RESULTS: 43.5% of the patients were very satisfied, 52.2% were satisfied and 4.34% were not satisfied. All osteotomies united without any hardware complications. The mean global AOFAS score improved significantly from a preoperative score of 55 points to 91.95 (p < 0.001). The intermetatarsal, hallux valgus angle, and DMMA improved from the mean preoperative values of 15.9 degrees, 31.2 degrees, and 14.1 degrees to 9.1 degrees, 15.2 degrees, and 8.4 degrees, respectively (p < 0.001 for all). One patient developed a superficial wound infection, which responded to antibiotics and one patient developed a painful spur at first MTPJ. CONCLUSION: We conclude that this is a safe and simple technique of fixing a Scarf osteotomy. It is cost effective, provides stable fixation and maintains correction until the osteotomy unites.

Successful treatment of dermatomyositis during pregnancy with intravenous immunoglobulin monotherapy.

BACKGROUND: Dermatomyositis is rare during pregnancy and, if untreated, is associated with poor fetal outcome. Corticosteroids are a standard treatment for dermatomyositis in pregnancy, but they have adverse effects. Intravenous immune globulin is an effective therapy for this condition and may have few adverse effects. CASE: A young, white primigravida presented with dermatomyositis at 4 5/7 weeks of gestation (creatine kinase 2,762 units/L). Intravenous immune globulin was administered monthly at a dose of 1 g/(kg.d) for 2 consecutive days. The patient's symptoms resolved and no complications were experienced during therapy. At term, creatine kinase was 29 units/L and a healthy 3,657.5-g (8-lb, 1-oz) neonate was born. CONCLUSION: Pregnant patients with dermatomyositis can be treated with intravenous immune globulin, resulting in good fetal outcome, thus avoiding the deleterious effects of corticosteroid therapy on pregnancy.

Workplace Violence in Mental Health: A Victorian Mental Health Workforce Survey.

The international literature suggests workplace violence in mental health settings is a significant issue, yet little is known about the frequency, nature, severity and health consequences of staff exposure to violence in Australian mental health services. To address this gap, we examined these aspects of workplace violence as reported by mental health services employees in Victoria, Australia. The project used a cross-sectional, exploratory descriptive design. A random sample of 1600 Health and Community Services Union members were invited to complete a survey investigating exposure to violence in the workplace, and related psychological health outcomes. Participants comprised employees from multiple disciplines including nursing, social work, occupational therapy, psychology and administration staff. A total of 411 members responded to the survey (26% response rate). Of the total sample, 83% reported exposure to at least one form of violence in the previous 12 months. The most frequently reported form of violence was verbal abuse (80%) followed by physical violence (34%) and then bullying/mobbing (30%). Almost one in three victims of violence (33%) rated themselves as being in psychological distress, 54% of whom reported being in severe psychological distress. The more forms of violence to which victims were exposed, the greater the frequency of reports of psychological distress. Workplace violence is prevalent in mental health facilities in Victoria. The nature, severity and health impact of this violence represents a serious safety concern for mental health employees. Strategies must be considered and implemented by healthcare management and policy makers to reduce and prevent violence.

Hexosamines regulate leptin production in 3T3-L1 adipocytes through transcriptional mechanisms.

This study was undertaken to examine the regulation of leptin gene (LEP) transcription and leptin release by hexosamines in 3T3-L1 adipocytes. Glucosamine (1 mM), an intermediate in hexosamine biosynthesis, increased leptin release to 117.0 +/- 7.3% (P = 0.0430; n = 9) and 134.6 +/- 6.5% of the control value (P = 0.0367; n = 4) by 48 and 96 h, respectively. With 0.01 mM glucosamine, leptin release was increased to 120.0 +/- 3.0% of the control value (P = 0.0069; n = 4) by 96 h of treatment. Glucose at 5 and 20 mM stimulated leptin release to 759 +/- 227% and 1104 +/- 316% of the control value over the 96-h culture period. Inhibition of hexosamine biosynthesis with 6-diazo-5-oxonorleucine (20 microM) reduced glucose-stimulated leptin release 13 +/- 2.3% and 29.9 +/- 6.6% at 24 and 96 h, respectively (n = 4; P < 0.05). A 24-h incubation in 5 mM glucose significantly increased (163.0 +/- 19.3%; n = 7) the activity of a human LEP promoter electroporated into differentiated 3T3-L1 cells. Glucosamine (1 mM; 48 h) also increased LEP promoter activity 170.0 +/- 13.0% (n = 5). Mutation of the three Sp1 binding sites in the LEP construct significantly reduced promoter activity. However, glucose (5 mM; 24 h) and glucosamine (1 mM; 48 h) increased the activity of the mutated promoter to 165 +/- 40% (n = 8) and 143 +/- 13% of the control value (n = 8). Glucosamine significantly increased O-glycosylation of Sp1 by 16.1 +/- 4.5% (P = 0.0305; n = 3). These data demonstrate that glucose and hexosamines regulate leptin production through transcriptional mechanisms localized to the proximal portion of the LEP promoter. Hexosamine-mediated regulation of LEP gene expression does not depend on Sp1 binding to traditional sites on the promoter.