2012

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Al-Latayfeh M, Silva PS, Sun JK, Aiello LP. Antiangiogenic therapy for ischemic retinopathies. Cold Spring Harb Perspect Med 2012;2(6):a006411.Abstract
Neovascularization is a common pathological process in various retinal vascular disorders including diabetic retinopathy (DR), age-related macular degeneration (AMD) and retinal vein occlusion (RVO). The development of neovascular vessels may lead to complications such as vitreous hemorrhage, fibrovascular tissue formation, and traction retinal detachments. Ultimately, irreversible vision loss may result. Various proangiogenic factors are involved in these complex processes. Different antiangiogenic drugs have been formulated in an attempt treat these vascular disorders. One factor that plays a major role in the development of retinal neovascularization is vascular endothelial growth factor (VEGF). Anti-VEGF agents are currently FDA approved for the treatment of AMD and RVO. They are also extensively used as an off-label treatment for diabetic macular edema (DME), proliferative DR, and neovascular glaucoma. However, at this time, the long-term safety of chronic VEGF inhibition has not been extensively evaluated. A large and rapidly expanding body of research on angiogenesis is being conducted at multiple centers across the globe to determine the exact contributions and interactions among a variety of angiogenic factors in an effort to determine the therapeutic potential of antiangiogenic agent in the treatment of a variety of retinal diseases.
Alhatem A, Cavalcanti B, Hamrah P. In vivo confocal microscopy in dry eye disease and related conditions. Semin Ophthalmol 2012;27(5-6):138-48.Abstract
A new era of ocular imaging has recently begun with the advent of in vivo confocal microscopy (IVCM), shedding more light on the pathophysiology, diagnosis, and potential treatment strategies for dry eye disease. IVCM is a noninvasive and powerful tool that allows detection of changes in ocular surface epithelium, immune and inflammatory cells, corneal nerves, keratocytes, and meibomian gland structures on a cellular level. Ocular surface structures in dry eye-related conditions have been assessed and alterations have been quantified using IVCM. IVCM may aid in the assessment of dry eye disease prognosis and treatment, as well as lead to improved understanding of the pathophysiological mechanisms in this complex disease. Further, due to visualization of subclinical findings, IVCM may allow detection of disease at much earlier stages and allow stratification of patients for clinical trials. Finally, by providing an objective methodology to monitor treatment efficacy, image-guided therapy may allow the possibility of tailoring treatment based on cellular changes, rather than on clinical changes alone.
Andreoli MT, Andreoli CM. Surgical rehabilitation of the open globe injury patient. Am J Ophthalmol 2012;153(5):856-60.Abstract
PURPOSE: To describe the long-term surgical course of patients with open globe injury. DESIGN: Retrospective case series. METHODS: Patients with open globe injuries (848 in total) treated surgically at the Massachusetts Eye and Ear Infirmary between 2000 and 2009 were retrospectively reviewed. Data from presentation, initial repair, and follow-up surgery were analyzed. RESULTS: Among 848 injuries, 1415 surgical procedures were performed. The mean follow-up time was 19.7 months, including 6017 visits. On average, patients required 1.7 surgeries and 7.1 follow-up visits. Factors predicting follow-up surgery included more severe ocular trauma score, worse prerepair visual acuity, retinal hemorrhage, anterior vitrectomy at primary repair, pars plana vitrectomy at primary repair, and lensectomy at primary repair. Patients with zone II injury, hemorrhagic choroidal detachment, and a history of previous ocular surgery tended to require follow-up surgery less frequently. Patients requiring a second surgery tended to have worse visual acuity at presentation and postrepair. Postoperative visual outcomes were worse for patients who underwent vitreoretinal follow-up surgery, likely because of mechanism of injury. Variables associated with inferior visual outcome were worse prerepair visual acuity, postoperative afferent pupillary defect (APD), old age, scleral laceration, and retinal detachment. CONCLUSION: Open globe injuries require significant surgical follow-up. Patients requiring multiple operations tended to have worse postoperative visual acuity. Patients who underwent vitreoretinal surgery had overall worse visual outcomes. While the first year of surveillance appears to be pivotal in the course of an open globe injury, these patients can expect long-term care from comprehensive and subspecialty ophthalmologists.
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Bansal AK, Singer JM, Anderson WS, Golby A, Madsen JR, Kreiman G. Temporal stability of visually selective responses in intracranial field potentials recorded from human occipital and temporal lobes. J Neurophysiol 2012;108(11):3073-86.Abstract
The cerebral cortex needs to maintain information for long time periods while at the same time being capable of learning and adapting to changes. The degree of stability of physiological signals in the human brain in response to external stimuli over temporal scales spanning hours to days remains unclear. Here, we quantitatively assessed the stability across sessions of visually selective intracranial field potentials (IFPs) elicited by brief flashes of visual stimuli presented to 27 subjects. The interval between sessions ranged from hours to multiple days. We considered electrodes that showed robust visual selectivity to different shapes; these electrodes were typically located in the inferior occipital gyrus, the inferior temporal cortex, and the fusiform gyrus. We found that IFP responses showed a strong degree of stability across sessions. This stability was evident in averaged responses as well as single-trial decoding analyses, at the image exemplar level as well as at the category level, across different parts of visual cortex, and for three different visual recognition tasks. These results establish a quantitative evaluation of the degree of stationarity of visually selective IFP responses within and across sessions and provide a baseline for studies of cortical plasticity and for the development of brain-machine interfaces.
Bitar MS, Liu C, Ziaei A, Chen Y, Schmedt T, Jurkunas UV. Decline in DJ-1 and decreased nuclear translocation of Nrf2 in Fuchs endothelial corneal dystrophy. Invest Ophthalmol Vis Sci 2012;53(9):5806-13.Abstract
PURPOSE: This study sought to determine factors involved in nuclear factor erythroid 2-related factor 2 (Nrf2) regulation and their response to oxidative stress in Fuchs endothelial corneal dystrophy (FECD) and normal corneal endothelial cells (CECs). METHODS: FECD corneal buttons were obtained from transplantations and normal human corneas from tissue banks. Oxidative stress was induced by tert-butyl hydroperoxide (tBHP). Protein and mRNA levels of Nrf2, DJ-1, p53, and Kelch-like ECH-associated protein1 (Keap1) were investigated using Western blotting and real-time PCR. Immunoprecipitation was used to detect levels of oxidized DJ-1 protein and Cullin 3- (Cul3)-regulated degradation of DJ-1 in immortalized FECD (FECDi) and normal CEC (HCECi) cell lines. Nrf2 subcellular localization was assessed by immunocytochemistry. RESULTS: Nrf2 protein stabilizer, DJ-1, decreased significantly in FECD CECs compared with normal, whereas Nrf2 protein repressor, Keap1, was unchanged at baseline but increased under oxidative stress. Under oxidative stress, normal CECs upregulated DJ-1 protein synthesis, whereas FECD CECs did not. DJ-1 decline correlated with increased DJ-1 oxidative modification and carbonylation in FECDi as compared with HCECi. Increased labeling of immunoprecipitated DJ-1 protein with anti-Cul3 antibody indicated enhanced DJ-1 degradation in FECDi as compared with HCECi. Following tBHP treatment, Nrf2 translocated from cytoplasm to nuclei in normal CECs, whereas Nrf2 nuclear localization was not observed in FECD. CONCLUSIONS: Decreased levels of DJ-1 in FECD at baseline and under oxidative stress correlate with impaired Nrf2 nuclear translocation and heightened cell susceptibility to apoptosis. Targeting the DJ-1/Nrf2 axis could yield a mechanism to slow CEC degeneration in FECD.
Bowers AR, Tant M, Peli E. A pilot evaluation of on-road detection performance by drivers with hemianopia using oblique peripheral prisms. Stroke Res Treat 2012;2012:176806.Abstract
Aims. Homonymous hemianopia (HH), a severe visual consequence of stroke, causes difficulties in detecting obstacles on the nonseeing (blind) side. We conducted a pilot study to evaluate the effects of oblique peripheral prisms, a novel development in optical treatments for HH, on detection of unexpected hazards when driving. Methods. Twelve people with complete HH (median 49 years, range 29-68) completed road tests with sham oblique prism glasses (SP) and real oblique prism glasses (RP). A masked evaluator rated driving performance along the 25 km routes on busy streets in Ghent, Belgium. Results. The proportion of satisfactory responses to unexpected hazards on the blind side was higher in the RP than the SP drive (80% versus 30%; P = 0.001), but similar for unexpected hazards on the seeing side. Conclusions. These pilot data suggest that oblique peripheral prisms may improve responses of people with HH to blindside hazards when driving and provide the basis for a future, larger-sample clinical trial. Testing responses to unexpected hazards in areas of heavy vehicle and pedestrian traffic appears promising as a real-world outcome measure for future evaluations of HH rehabilitation interventions aimed at improving detection when driving.
Burbank KS, Kreiman G. Depression-biased reverse plasticity rule is required for stable learning at top-down connections. PLoS Comput Biol 2012;8(3):e1002393.Abstract
Top-down synapses are ubiquitous throughout neocortex and play a central role in cognition, yet little is known about their development and specificity. During sensory experience, lower neocortical areas are activated before higher ones, causing top-down synapses to experience a preponderance of post-synaptic activity preceding pre-synaptic activity. This timing pattern is the opposite of that experienced by bottom-up synapses, which suggests that different versions of spike-timing dependent synaptic plasticity (STDP) rules may be required at top-down synapses. We consider a two-layer neural network model and investigate which STDP rules can lead to a distribution of top-down synaptic weights that is stable, diverse and avoids strong loops. We introduce a temporally reversed rule (rSTDP) where top-down synapses are potentiated if post-synaptic activity precedes pre-synaptic activity. Combining analytical work and integrate-and-fire simulations, we show that only depression-biased rSTDP (and not classical STDP) produces stable and diverse top-down weights. The conclusions did not change upon addition of homeostatic mechanisms, multiplicative STDP rules or weak external input to the top neurons. Our prediction for rSTDP at top-down synapses, which are distally located, is supported by recent neurophysiological evidence showing the existence of temporally reversed STDP in synapses that are distal to the post-synaptic cell body.
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Cai S, Smith ME, Redenti SM, Wnek GE, Young MJ. Mouse retinal progenitor cell dynamics on electrospun poly (ϵ-caprolactone). J Biomater Sci Polym Ed 2012;23(11):1451-65.Abstract
Age-related macular degeneration, retinitis pigmentosa and glaucoma are among the many retinal degenerative diseases where retinal cell death leads to irreversible vision loss and blindness. Working toward a cell-replacement-based therapy for such diseases, a number of research groups have recently evaluated the feasibility of using retinal progenitor cells (RPCs) cultured and transplanted on biodegradable polymer substrates to replace damaged retinal tissue. Appropriate polymer substrate design is essential to providing a three-dimensional environment that can facilitate cell adhesion, proliferation and post-transplantation migration into the host environment. In this study, we have designed and fabricated a novel, ultra-thin electrospun poly(ϵ-caprolactone) (PCL) scaffold with microscale fiber diameters, appropriate porosity for infiltration by RPCs, and biologically compatible mechanical characteristics. We have verified that our electrospun PCL scaffold supports robust mouse RPC proliferation, adhesion, and differentiation in vitro, as well as migration into mouse retinal explants. These promising results make PCL a strong candidate for further development as a cell transplantation substrate in retinal regenerative research.
Callahan AB, Jakobiec FA, Zakka FR, Fay A. Isolated unilateral linear epidermal nevus of the upper eyelid. Ophthalmic Plast Reconstr Surg 2012;28(6):e135-8.Abstract
A 75-year-old man presented with a recurrent, unilateral, solitary, linear, corrugated lesion of the right upper eyelid of prolonged duration together with bilateral dermatochalasis. A re-excision with blepharoplasty was performed. Histopathologic analysis of the tissue revealed parallel linear arrays of papillomatosis and acanthosis with overlying basket-weave hyperkeratosis consistent with a linear epidermal nevus. Immunohistochemical studies disclosed normal numbers of intraepidermal melanocytes and Langerhans cells without Merkel cells or an increase in cycling keratinocytes. Although the term "nevus" is mostly used in conjunction with the common nevomelanocytic nevus, in fact nevi of other cutaneous cellular elements can occur on a malformational basis (such as sebaceous, eccrine, apocrine, pilar, and elastic fiber nevi). Ophthalmologists should be aware of epidermal nevi because they are rarely associated with cataracts, malignant cutaneous neoplasms, neurologic abnormalities, and musculoskeletal disorders. For focal lesions like the present one, local excision is appropriate. A select differential diagnosis of histopathologically related conditions is provided.
Callahan AB, Yoon MK. Infantile hemangiomas: A review. Saudi J Ophthalmol 2012;26(3):283-91.Abstract
Infantile hemangiomas (IH) are the most common eyelid and orbital tumors of childhood. Although they are considered benign lesions that have a generally self-limited course, in the periocular region, they have the potential to cause amblyopia, strabismus, and severe disfigurement. The decision for treatment can be a source of anxiety for patients, parents, and physicians alike. There are numerous treatment modalities, including emerging therapies that may make treatment safer and more effective than ever before. This review discusses our current understanding of this disease, its management, and future therapies.
Cepko CL. Emerging gene therapies for retinal degenerations. J Neurosci 2012;32(19):6415-20.
Chen J, Stahl A, Krah NM, Seaward MR, Joyal J-S, Juan AM, Hatton CJ, Aderman CM, Dennison RJ, Willett KL, Sapieha P, Smith LEH. Retinal expression of Wnt-pathway mediated genes in low-density lipoprotein receptor-related protein 5 (Lrp5) knockout mice. PLoS One 2012;7(1):e30203.Abstract
Mutations in low-density lipoprotein receptor-related protein 5 (Lrp5) impair retinal angiogenesis in patients with familial exudative vitreoretinopathy (FEVR), a rare type of blinding vascular eye disease. The defective retinal vasculature phenotype in human FEVR patients is recapitulated in Lrp5 knockout (Lrp5(-/-)) mouse with delayed and incomplete development of retinal vessels. In this study we examined gene expression changes in the developing Lrp5(-/-) mouse retina to gain insight into the molecular mechanisms that underlie the pathology of FEVR in humans. Gene expression levels were assessed with an Illumina microarray on total RNA from Lrp5(-/-) and WT retinas isolated on postnatal day (P) 8. Regulated genes were confirmed using RT-qPCR analysis. Consistent with a role in vascular development, we identified expression changes in genes involved in cell-cell adhesion, blood vessel morphogenesis and membrane transport in Lrp5(-/-) retina compared to WT retina. In particular, tight junction protein claudin5 and amino acid transporter slc38a5 are both highly down-regulated in Lrp5(-/-) retina. Similarly, several Wnt ligands including Wnt7b show decreased expression levels. Plasmalemma vesicle associated protein (plvap), an endothelial permeability marker, in contrast, is up-regulated consistent with increased permeability in Lrp5(-/-) retinas. Together these data suggest that Lrp5 regulates multiple groups of genes that influence retinal angiogenesis and may contribute to the pathogenesis of FEVR.
Chen J, Smith LEH. Protective inflammasome activation in AMD. Nat Med 2012;18(5):658-60.Abstract
Age-related macular degeneration (AMD) is the most common cause of blindness in the elderly. AMD progression is associated with alterations in inflammatory pathways and the immune system. A new study identifies a protective role for inflammasomes in AMD, suggesting that inflammasome activation might be manipulated as a potential therapeutic strategy for this condition (pages 791-798).
Chen J, Joyal J-S, Hatton CJ, Juan AM, Pei DT, Hurst CG, Xu D, Stahl A, Hellstrom A, Smith LEH. Propranolol inhibition of β-adrenergic receptor does not suppress pathologic neovascularization in oxygen-induced retinopathy. Invest Ophthalmol Vis Sci 2012;53(6):2968-77.Abstract
PURPOSE: Retinopathy of prematurity (ROP) is a leading cause of blindness in children and is, in its most severe form, characterized by uncontrolled growth of vision-threatening pathologic vessels. Propranolol, a nonselective β-adrenergic receptor blocker, was reported to protect against pathologic retinal neovascularization in a mouse model of oxygen-induced retinopathy (OIR). Based on this single animal study using nonstandard evaluation of retinopathy, clinical trials are currently ongoing to evaluate propranolol treatment in stage 2 ROP patients who tend to experience spontaneous disease regression and are at low risk of blindness. Because these ROP patients are vulnerable premature infants who are still in a fragile state of incomplete development, the efficacy of propranolol treatment in retinopathy needs to be evaluated thoroughly in preclinical animal models of retinopathy and potential benefits weighed against potential adverse effects. METHODS: Retinopathy was induced by exposing neonatal mice to 75% oxygen from postnatal day (P) 7 to P12. Three routes of propranolol treatment were assessed from P12 to P16: oral gavage, intraperitoneal injection, or subcutaneous injection, with doses varying between 2 and 60 mg/kg/day. At P17, retinal flatmounts were stained with isolectin and quantified with a standard protocol to measure vasoobliteration and pathologic neovascularization. Retinal gene expression was analyzed with qRT-PCR using RNA isolated from retinas of control and propranolol-treated pups. RESULTS: None of the treatment approaches at any dose of propranolol (up to 60 mg/kg/day) were effective in preventing the development of retinopathy in a mouse model of OIR, evaluated using standard techniques. Propranolol treatment also did not change retinal expression of angiogenic factors including vascular endothelial growth factor. CONCLUSIONS: Propranolol treatment via three routes and up to 30 times the standard human dose failed to suppress retinopathy development in mice. These data bring into question whether propranolol through inhibition of β-adrenergic receptors is an appropriate therapeutic approach for treating ROP.
Cheng S-F, Dastjerdi MH, Ferrari G, Okanobo A, Bower KS, Ryan DS, Amparo F, Stevenson W, Hamrah P, Nallasamy N, Dana R. Short-term topical bevacizumab in the treatment of stable corneal neovascularization. Am J Ophthalmol 2012;154(6):940-948.e1.Abstract
PURPOSE: To evaluate the safety and efficacy of topical bevacizumab in the treatment of corneal neovascularization. DESIGN: Prospective, nonrandomized, interventional case series. METHODS: setting: Institutional, multicenter clinical trial. study population: Twenty eyes from 20 patients with stable corneal neovascularization. intervention procedures: Patients were treated with topical 1.0% bevacizumab for 3 weeks and were monitored for a total of 24 weeks. main outcome measures: Primary outcome measures included: neovascular area, defined as the area of the corneal vessels themselves; vessel caliber, defined as the mean corneal vessel diameter; and invasion area, defined as the fraction of the total cornea into which the vessels extended. The occurrence of ocular and systemic adverse events was monitored closely. RESULTS: As compared with the baseline visit, patients exhibited a statistically significant improvement in neovascular area by week 6 (P = .007) and in vessel caliber by week 12 (P = .006). At the final visit, neovascular area, vessel caliber, and invasion area were reduced by 47.5%, 36.2%, and 20%, respectively. The decreases in neovascular area and vessel caliber were statistically significant (P < .001 and P = .003, respectively); however, the reduction in invasion area did not reach statistical significance (P = .06). There were no significant changes in the secondary outcomes, and there were no adverse events. CONCLUSIONS: Short-term topical bevacizumab treatment reduced the extent of stable corneal neovascularization as measured by neovascular area and vessel caliber with no associated adverse events. Interestingly, the degree of treatment efficacy was inversely proportional to the baseline invasion area.
Chui TYP, Bissig D, Berkowitz BA, Akula JD. Refractive Development in the "ROP Rat". J Ophthalmol 2012;2012:956705.Abstract
Although retinopathy of prematurity (ROP) is clinically characterized by abnormal retinal vessels at the posterior pole of the eye, it is also commonly characterized by vascular abnormalities in the anterior segment, visual dysfunction which is based in retinal dysfunction, and, most commonly of all, arrested eye growth and high refractive error, particularly (and paradoxically) myopia. The oxygen-induced retinopathy rat model of ROP presents neurovascular outcomes similar to the human disease, although it is not yet known if the "ROP rat" also models the small-eyed myopia characteristic of ROP. In this study, magnetic resonance images (MRIs) of albino (Sprague-Dawley) and pigmented (Long-Evans) ROP rat eyes, and age- and strain-matched room-air-reared (RAR) controls, were examined. The positions and curvatures of the various optical media were measured and the refractive state (℞) of each eye estimated based on a previously published model. Even in adulthood (postnatal day 50), Sprague-Dawley and Long-Evans ROP rats were significantly myopic compared to strain-matched controls. The myopia in the Long-Evans ROP rats was more severe than in the Sprague-Dawley ROP rats, which also had significantly shorter axial lengths. These data reveal the ROP rat to be a novel and potentially informative approach to investigating physiological mechanisms in myopia in general and the myopia peculiar to ROP in particular.
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D K, R Z, X G, AE H, JW R, JD Z. Novel in Vitro Model for Keratoconus Disease. J Funct Biomater 2012;3(4):760-775.
Dagi LR, Bhargava A, Melvin P, Prabhu SP. Associated signs, demographic characteristics, and management of dacryocystocele in 64 infants. J AAPOS 2012;16(3):255-60.Abstract
PURPOSE: To describe the incidence of associated infection, respiratory compromise, apparent intranasal cyst, as well as sex, laterality, and age at presentation in 64 infants with dacryocystocele and to assess characteristics associated with successful interventions. METHODS: A retrospective chart review of all patients with dacryocystocele seen at Children's Hospital Boston between 1996 and 2010 was performed. Inclusion criteria were accuracy of diagnosis, treatment, and follow-up at our institution. Interventions were divided into 3 categories: procedures that did not require general anesthesia; simple procedures requiring general anesthesia, such as nasolacrimal probing with or without stent or balloon dilation; and more complex procedures under general anesthesia, specifically, those aided by intranasal endoscopy. RESULTS: Of the 90 identified patients, 64 met inclusion criteria. The majority of patients were female (63%) and had unilateral involvement (77%). More than one-half of all patients were successfully treated without anesthesia; however, patients presenting with infection were more likely to be treated with a simple procedure under general anesthesia. All patients treated endoscopically had intranasal cysts. Age, sex, and infection did not predict the use of intranasal endoscopy. Bilaterality of dacryocystocele was associated with the use of an endoscopic approach. CONCLUSIONS: Many infants with dacryocystocoele can be successfully treated without general anesthesia. The incidence of occult intranasal cyst among those treated without endoscopy remains unknown. Patients who were treated under general anesthesia but without the use of nasal endoscopy were more likely to have an infected system, but the clinical significance of this association is not clear.
Daniels AB, Lee J-E, MacConaill LE, Palescandolo E, van Hummelen P, Adams SM, Deangelis MM, Hahn WC, Gragoudas ES, Harbour WJ, Garraway LA, Kim IK. High throughput mass spectrometry-based mutation profiling of primary uveal melanoma. Invest Ophthalmol Vis Sci 2012;53(11):6991-6.Abstract
PURPOSE: We assessed for mutations in a large number of oncogenes and tumor suppressor genes in primary uveal melanomas using a high-throughput profiling system. METHODS: DNA was extracted and purified from 134 tissue samples from fresh-frozen tissues (n = 87) or formalin-fixed, paraffin-embedded tissues (n = 47) from 124 large uveal melanomas that underwent primary treatment by enucleation. DNA was subjected to whole genome amplification and MALDI-TOF mass spectrometry-based mutation profiling (>1000 mutations tested across 120 oncogenes and tumor suppressor genes) using the OncoMap3 platform. All candidate mutations, as well as commonly occurring mutations in GNAQ and GNA11, were validated using homogeneous mass extension (hME) technology. RESULTS: Of 123 samples, 97 (79%, representing 89 unique tumors) were amplified successfully, passed all quality control steps, and were assayed with the OncoMap platform. A total of 58 mutation calls was made for 49 different mutations across 26 different genes in 34/98 (35%) samples. Of 91 tumors that underwent hME validation, 83 (91%) harbored mutations in the GNAQ (47%) or GNA11 (44%) genes, while hME validation revealed two tumors with mutations in EGFR. These additional mutations occurred in tumors that also had mutations in GNAQ or GNA11. CONCLUSIONS: The vast majority of primary large uveal melanomas harbor mutually-exclusive mutations in GNAQ or GNA11, but very rarely have the oncogenic mutations that are reported commonly in other cancers. When present, these other mutations were found in conjunction with GNAQ/GNA11 mutations, suggesting that these other mutations likely are not the primary drivers of oncogenesis in uveal melanoma.
Daniels AB, Sandberg MA, Chen J, Weigel-DiFranco C, Fielding Hejtmancic J, Berson EL. Genotype-phenotype correlations in Bardet-Biedl syndrome. Arch Ophthalmol 2012;130(7):901-7.Abstract
OBJECTIVE: To determine whether mutations in different Bardet-Biedl syndrome (BBS) genes result in different ocular phenotypes. METHODS: Thirty-seven patients from 31 families were enrolled who met the clinical criteria for BBS and for whom a BBS mutation had been identified. Seventeen patients harbored mutations in BBS1, 10 in BBS10, and 10 in other genes (BBS2, BBS3, BBS5, BBS7, and BBS12). All the patients underwent ocular examination; 36 patients had computerized full-field electroretinograms (ERGs). RESULTS: Visual acuity was significantly better in BBS1 patients than in patients with other BBS mutations (P=.01), and a larger proportion of BBS1 patients had good (≥20/50) visual acuity (P=.01). The ERG amplitudes were significantly higher in BBS1 patients than in patients with other BBS mutations in response to 0.5-Hz and 30-Hz flashes (P<.001 for both). All the BBS1 patients harbored at least 1 missense mutation compared with only 45% of patients with mutations in other BBS genes (P<.001); the rest harbored only null alleles. However, multivariate analysis demonstrated that visual acuity or ERG amplitude did not depend on the type of mutation present (missense or null) when controlling for BBS gene. Prevalences of bone spicule pigmentation and cataract were comparable in BBS subtypes. CONCLUSIONS: Patients with BBS1 mutations had a milder phenotype than did patients with mutations in other BBS genes. Clinically, this manifested as significantly better visual acuity and larger ERG amplitudes. CLINICAL RELEVANCE: These phenotypic differences can help guide genetic testing and genetic counseling for patients with this syndrome.

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