Choi CJ, Bauza A, Yoon MK, Sobel RK, Freitag SK. Full-Thickness Skin Graft as an Independent or Adjunctive Technique for Repair of Cicatricial Lower Eyelid Ectropion Secondary to Actinic Skin Changes. Ophthal Plast Reconstr Surg 2015;31(6):474-7.Abstract

PURPOSE: To retrospectively review and describe full-thickness skin graft repair of lower eyelid cicatricial ectropion secondary to actinic skin. METHODS: A retrospective, noncomparative chart review of all patients who underwent lower eyelid ectropion repair with placement of a full-thickness skin graft between June 2004 and March 2014 was conducted with IRB approval. The etiology of lower eyelid ectropion, demographics including age, gender, ethnicity, laterality, graft donor site, additional surgical procedures, graft viability, surgical success rate, complications, and clinical exam findings were summarized. RESULTS: Twenty-nine eyelids in 24 patients underwent skin grafting for repair of cicatricial ectropion secondary to actinic skin changes. Ninety six percent of patients were male and 96% were Caucasian. Donor sites for skin grafts included upper eyelid (9, 31%), supraclavicular skin (9, 31%), postauricular skin (7, 24%), inner brachial skin (2, 7%), axilla (1, 3.5%), and preauricular skin (1, 3.5%). Twenty-four of 29 eyelids in the series underwent 1 or more additional procedures at the time of full-thickness skin grafting, including lateral tarsal strip (9 eyelids, 37.5%), punctoplasty (8, 33%), canthoplasty (7, 29%), excision of keratinized conjunctiva (2, 8%), transverse tarsotomy (1, 4%), ipsilateral external dacryocystorhinostomy (3, 12.5%), and lesion removal (1, 4%). There was 100% viability of the skin grafts. Overall surgical success rate was 76%, with asymptomatic recurrence rate of 17% and symptomatic recurrence rate of 7%. CONCLUSION: Repair of cicatricial lower eyelid ectropion secondary to actinic skin changes may be accomplished with full-thickness skin grafting, and is often performed in conjunction with additional procedures to fully address anatomic abnormalities.

Zhang C, Zhang Q, Wang F, Liu Q. Knockdown of poc1b causes abnormal photoreceptor sensory cilium and vision impairment in zebrafish. Biochem Biophys Res Commun 2015;465(4):651-7.Abstract

Proteomic analysis of the mouse photoreceptor sensory cilium identified a set of cilia proteins, including Poc1 centriolar protein b (Poc1b). Previous functional studies in human cells and zebrafish embryos implicated that Poc1b plays important roles in centriole duplication and length control, as well as ciliogenesis. To study the function of Poc1b in photoreceptor sensory cilia and other primary cilia, we expressed a tagged recombinant Poc1b protein in cultured renal epithelial cells and rat retina. Poc1b was localized to the centrioles and spindle bundles during cell cycle progression, and to the basal body of photoreceptor sensory cilia. A morpholino knockdown and complementation assay of poc1b in zebrafish showed that loss of poc1b led to a range of morphological anomalies of cilia commonly associated with human ciliopathies. In the retina, the development of retinal laminae was significantly delayed and the length of photoreceptor outer segments was shortened. Visual behavior studies revealed impaired visual function in the poc1b morphants. In addition, ciliopathy-associated developmental defects, such as small eyes, curved body axis, heart defects, and shortened cilia in Kupffer's vesicle, were observed as well. These data suggest that poc1b is required for normal development and ciliogenesis of retinal photoreceptor sensory cilia and other cilia. Furthermore, this conclusion is supported by recent findings that mutations in POC1B gene have been identified in patients with inherited retinal dystrophy and syndromic retinal ciliopathy.

Fernandez-Godino R, Garland DL, Pierce EA. A local complement response by RPE causes early-stage macular degeneration. Hum Mol Genet 2015;24(19):5555-69.Abstract

Inherited and age-related macular degenerations (AMDs) are important causes of vision loss. An early hallmark of these disorders is the formation of sub-retinal pigment epithelium (RPE) basal deposits. A role for the complement system in MDs was suggested by genetic association studies, but direct functional connections between alterations in the complement system and the pathogenesis of MD remain to be defined. We used primary RPE cells from a mouse model of inherited MD due to a p.R345W mutation in EGF-containing fibulin-like extracellular matrix protein 1 (EFEMP1) to investigate the role of the RPE in early MD pathogenesis. Efemp1(R345W) RPE cells recapitulate the basal deposit formation observed in vivo by producing sub-RPE deposits in vitro. The deposits share features with basal deposits, and their formation was mediated by EFEMP1(R345W) or complement component 3a (C3a), but not by complement component 5a (C5a). Increased activation of complement appears to occur in response to an abnormal extracellular matrix (ECM), generated by the mutant EFEMP1(R345W) protein and reduced ECM turnover due to inhibition of matrix metalloproteinase 2 by EFEMP1(R345W) and C3a. Increased production of C3a also stimulated the release of cytokines such as interleukin (IL)-6 and IL-1B, which appear to have a role in deposit formation, albeit downstream of C3a. These studies provide the first direct indication that complement components produced locally by the RPE are involved in the formation of basal deposits. Furthermore, these results suggest that C3a generated by RPE is a potential therapeutic target for the treatment of EFEMP1-associated MD as well as AMD.

Müller RT, Pourmirzaie R, Pavan-Langston D, Cavalcanti BM, Aggarwal S, Colón C, Jamali A, Cruzat A, Hamrah P. In Vivo Confocal Microscopy Demonstrates Bilateral Loss of Endothelial Cells in Unilateral Herpes Simplex Keratitis. Invest Ophthalmol Vis Sci 2015;56(8):4899-906.Abstract

PURPOSE: To report bilateral corneal endothelial cell density (ECD), as well as its correlation with subbasal nerve changes, in patients with unilateral herpes simplex keratitis (HSK). METHODS: Thirty-six eyes of 36 patients with corneal scarring caused by HSK, as well as their respective contralateral clinically unaffected eyes, were prospectively studied and compared with 26 eyes of 26 healthy volunteers. In vivo confocal microscopy and corneal sensation of the central cornea were performed bilaterally in all patients and in one random eye of controls. The ECD and subbasal corneal nerve density, including the lengths of total nerves, main trunks, and branches were evaluated and correlated to central corneal sensation. RESULTS: The ECD was significantly lower in eyes affected with HSK than in controls (2304 ± 578 vs. 2940 ± 370 cells/mm2, P < 0.0001). Surprisingly, lower ECD was also detected in contralateral clinically unaffected eyes (2548 ± 423), compared to controls (P = 0.02). Both affected and contralateral eyes showed decrease in total nerve length, compared to controls (10.0 ± 6.3 vs. 17.6 ± 6.3 vs. 21.9 ± 4.3 mm/mm2, respectively; P < 0.05 for all). The ECD correlated positively with total nerve length (r = 0.39, P = 0.0009) and with corneal sensation (r = 0.31, P = 0.009). CONCLUSIONS: In vivo confocal microscopy findings demonstrated alterations in corneal ECD in both affected and clinically unaffected contralateral eyes of patients with unilateral HSK. Moreover, the positive significant correlation between the ECD and the subbasal nerve density may suggest a potential link between corneal innervation and corneal endothelial cell homeostasis.

Choi VW, Bigelow CE, McGee TL, Gujar AN, Li H, Hanks SM, Vrouvlianis J, Maker M, Leehy B, Zhang Y, Aranda J, Bounoutas G, Demirs JT, Yang J, Ornberg R, Wang Y, Martin W, Stout KR, Argentieri G, Grosenstein P, Diaz D, Turner O, Jaffee BD, Police SR, Dryja TP. AAV-mediated RLBP1 gene therapy improves the rate of dark adaptation in Rlbp1 knockout mice. Mol Ther Methods Clin Dev 2015;2:15022.Abstract

Recessive mutations in RLBP1 cause a form of retinitis pigmentosa in which the retina, before its degeneration leads to blindness, abnormally slowly recovers sensitivity after exposure to light. To develop a potential gene therapy for this condition, we tested multiple recombinant adeno-associated vectors (rAAVs) composed of different promoters, capsid serotypes, and genome conformations. We generated rAAVs in which sequences from the promoters of the human RLBP1, RPE65, or BEST1 genes drove the expression of a reporter gene (green fluorescent protein). A promoter derived from the RLBP1 gene mediated expression in the retinal pigment epithelium and Müller cells (the intended target cell types) at qualitatively higher levels than in other retinal cell types in wild-type mice and monkeys. With this promoter upstream of the coding sequence of the human RLBP1 gene, we compared the potencies of vectors with an AAV2 versus an AAV8 capsid in transducing mouse retinas, and we compared vectors with a self-complementary versus a single-stranded genome. The optimal vector (scAAV8-pRLBP1-hRLBP1) had serotype 8 capsid and a self-complementary genome. Subretinal injection of scAAV8-pRLBP1-hRLBP1 in Rlbp1 nullizygous mice improved the rate of dark adaptation based on scotopic (rod-plus-cone) and photopic (cone) electroretinograms (ERGs). The effect was still present after 1 year.

Chang Y-H, Melvin P, Dagi LR. Goal-determined metrics to assess outcomes ofexotropia surgery. J AAPOS 2015;Abstract

PURPOSE: To present a goal-determined methodology for monitoring outcomes after surgery for exotropia. METHODS: The goal-determined metric required surgeons to rank four possible goals preoperatively: (1) binocular potential, (2) restoration of eye contact, (3) diplopia control; and (4) torticollis management. Potential preoperative risk factors were noted. Goal-specific outcomes criteria were applied to the latest sensory-motor examination, 2-6 months after surgery. The medical records of patients who underwent surgery from 2007 to 2012 were retrospectively reviewed with respect to the goal-directed metric. RESULTS: A total of 852 patients were evaluated in the study period: 411 for restoration of eye contact; 347 for binocular potential; 78 for diplopia resolution; and16 for torticollis management. Excellent (62%) or good (16%) outcomes were achieved in 78%. Procedures to resolve diplopia (OR, 6.56; 95% CI, 3.39-12.68) and to restore eye contact (OR, 3.74; 95% CI, 2.65-5.29) were more likely to result in excellent outcomes than procedures to improve binocular potential. Simultaneous surgery for dissociated vertical deviation (OR, 0.38; 95% CI, 0.16-0.92) and preoperative near deviation ≥50(Δ) (OR, 0.27; 95% CI, 0.17-0.42) limited likelihood of an excellent outcome. Outcomes monitored by simultaneous rather than alternate prism and cover test were more likely graded excellent (OR, 5.16; 95% CI, 3.50-7.62). Applying motor criteria from the binocular potential goal to the entire cohort diminished putative outcomes (P < 0.001). CONCLUSIONS: Goal-determined metric monitoring outcomes of exotropia surgery provides outcomes germane to the reason for intervention, enables analysis of risk factors affecting outcomes, and facilitates reporting on heterogeneous populations.

Wirostko B, Rafii MJ, Sullivan DA, Morelli J, Ding J. Novel Therapy to Treat Corneal Epithelial Defects: A Hypothesis with Growth Hormone. Ocul Surf 2015;13(3):204-212.e1.Abstract

Impaired corneal wound healing that occurs with ocular surface disease, trauma, systemic disease, or surgical intervention can lead to persistent corneal epithelial defects (PCED), which result in corneal scarring, ulceration, opacification, corneal neovascularization, and, ultimately, visual compromise and vision loss. The current standard of care can include lubricants, ointments, bandage lenses, amniotic membranes, autologous serum eye drops, and corneal transplants. Various inherent problems exist with application and administration of these treatments, which often may not result in a completely healed surface. A topically applicable compound capable of promoting corneal epithelial cell proliferation and/or migration would be ideal to accelerate healing. We hypothesize that human growth hormone (HGH) is such a compound. In a recent study, HGH was shown to activate signal transducer and activators of transcription-5 (STAT5) signaling and promote corneal wound healing by enhancing corneal epithelial migration in a co-culture system of corneal epithelial cells and fibroblasts. These effects require an intact communication between corneal epithelia and fibroblasts. Further, HGH promotes corneal wound healing in a rabbit debridement model, thus demonstrating the effectiveness of HGH in vivo as well. In conclusion, HGH may represent an exciting and effective topical therapeutic to promote corneal wound healing.

Grob SR, Jakobiec FA, Stagner AM, Colby KA. Diffuse Epibulbar Complex Lacrimal-Cartilaginous Choristoma: Diagnostic Clues and Management. Cornea 2015;34(10):1321-3.Abstract

PURPOSE: To describe the clinical and histopathologic features distinguishing an extensive complex choristoma of the epibulbar surface and to address the management of such lesions. METHODS: Clinical history, diagnostic imaging studies, and histopathologic sections stained with hematoxylin and eosin were reviewed from a 2-year-old girl with a congenital conjunctival lesion of the right eye that was surgically excised. RESULTS: The patient clinically displayed an extensive, vascularized amelanotic conjunctival lesion located superotemporally with extension onto the cornea. Her visual acuity was reduced to 20/670. The clinical diagnosis was a large lacrimal gland choristoma with corneal involvement and resulting deprivation amblyopia. The patient underwent an excision of the lesion including the corneal portion, and the ocular surface was reconstructed with amniotic membrane. Histopathologic evaluation disclosed lobules of lacrimal tissue and cartilage plaques, smooth muscle, and nerves consistent with a complex choristoma. Six weeks postoperatively, the visual acuity had improved to 20/180. The patient returned to her local ophthalmologist for amblyopia management. CONCLUSIONS: We emphasize the importance of recognizing lesion-induced amblyopia and the timely performance of appropriate surgery for complex epibulbar choristomas. A differential diagnosis of other congenital epibulbar lesions is provided.

Gong Y, Li J, Sun Y, Fu Z, Liu C-H, Evans L, Tian K, Saba N, Fredrick T, Morss P, Chen J, Smith LEH. Optimization of an Image-Guided Laser-Induced Choroidal Neovascularization Model in Mice. PLoS One 2015;10(7):e0132643.Abstract

The mouse model of laser-induced choroidal neovascularization (CNV) has been used in studies of the exudative form of age-related macular degeneration using both the conventional slit lamp and a new image-guided laser system. A standardized protocol is needed for consistent results using this model, which has been lacking. We optimized details of laser-induced CNV using the image-guided laser photocoagulation system. Four lesions with similar size were consistently applied per eye at approximately double the disc diameter away from the optic nerve, using different laser power levels, and mice of various ages and genders. After 7 days, the mice were sacrificed and retinal pigment epithelium/choroid/sclera was flat-mounted, stained with Isolectin B4, and imaged. Quantification of the area of the laser-induced lesions was performed using an established and constant threshold. Exclusion criteria are described that were necessary for reliable data analysis of the laser-induced CNV lesions. The CNV lesion area was proportional to the laser power levels. Mice at 12-16 weeks of age developed more severe CNV than those at 6-8 weeks of age, and the gender difference was only significant in mice at 12-16 weeks of age, but not in those at 6-8 weeks of age. Dietary intake of omega-3 long-chain polyunsaturated fatty acid reduced laser-induced CNV in mice. Taken together, laser-induced CNV lesions can be easily and consistently applied using the image-guided laser platform. Mice at 6-8 weeks of age are ideal for the laser-induced CNV model.

Haun AM, Peli E. Similar Sensitivity to Ladder Contours in Macular Degeneration Patients and Controls. PLoS One 2015;10(7):e0128119.Abstract

PURPOSE: To determine whether people with central field loss (CFL) from macular degeneration have improved ability to recognize a particularly difficult spatial configuration embedded in noise, the peripherally-viewed 'ladder contour'. The visibility of these configuration has been linked to general contour integration ability and crowding limitations in peripheral vision. METHODS: We used a trial-based yes-no task. CFL patients and normally-sighted controls performed the task, looking for ladder contours embedded in a field of randomly oriented Gabor patches, at a range of stimulus presentation times (varying stimulus difficulty). Viewing eccentricity in CFL patients was set by their preferred retinal loci (PRLs) and matched artificially in the control group. The contours were presented so as to be tangent to the CFL region, given a patient's PRL location. RESULTS: CFL and normally-sighted groups performed similarly on the task. The only significant determinant of performance was the viewing eccentricity. CONCLUSIONS: CFL patients do not seem to develop any improved ability to recognize ladder contours with their parafoveal retina, which suggests that there is no underlying improvement in contour integration or reduction in crowding limitations in the region of the PRL despite extended daily use.

Kothari S, Foster SC, Pistilli M, Liesegang TL, Daniel E, Sen NH, Suhler EB, Thorne JE, Jabs DA, Levy-Clarke GA, Nussenblatt RB, Rosenbaum JT, Lawrence SD, Kempen JH, for Eye Diseases Group SITR. The Risk of Intraocular Pressure Elevation inPediatric Noninfectious Uveitis. Ophthalmology 2015;122(10):1987-2001.Abstract

PURPOSE: To characterize the risk and risk factors for intraocular pressure (IOP) elevation in pediatric noninfectious uveitis. DESIGN: Multicenter retrospective cohort study. PARTICIPANTS: Nine hundred sixteen children (1593 eyes) younger than 18 years at presentation with noninfectious uveitis followed up between January 1978 and December 2007 at 5 academic uveitis centers in the United States. METHODS: Medical records review by trained, certified experts. MAIN OUTCOME MEASURES: Prevalence and incidence of IOP of 21 mmHg or more and 30 mmHg or more and incidence of a rise in IOP by 10 mmHg or more. To avoid underascertainment, outcomes were counted as present when IOP-lowering therapies were in use. RESULTS: Initially, 251 (15.8%) and 46 eyes (2.9%) had IOP ≥21 mmHg and ≥30 mmHg, respectively. Factors significantly associated with presenting IOP elevation included age of 6 to 12 years (versus other pediatric ages), prior cataract surgery, pars plana vitrectomy, duration of uveitis ≥6 months, contralateral IOP elevation, presenting visual acuity worse than 20/40, and topical corticosteroid use (in a dose-response relationship). The median follow-up was 1.25 years (interquartile range, 0.4-3.66). The estimated incidence of any observed IOP elevation to ≥21 mmHg, to ≥30 mmHg, and increase in IOP by ≥10 mmHg was 33.4%, 14.8%, and 24.4%, respectively, within 2 years. Factors associated with IOP elevation included pars plana vitrectomy, contralateral IOP elevation (adjusted hazard ratio [aHR], up to 9.54; P < 0.001), and the use of topical (aHR, up to 8.77 that followed a dose-response relationship; P < 0.001), periocular (aHR, up to 7.96; P < 0.001), and intraocular (aHR, up to 19.7; P < 0.001) corticosteroids. CONCLUSIONS: Intraocular pressure elevation affects a large minority of children with noninfectious uveitis. Statistically significant risk factors include IOP elevation or use of IOP-lowering treatment in the contralateral eye and local corticosteroid use that demonstrated a dose-and route of administration-dependent relationship. In contrast, use of immunosuppressive drug therapy did not increase such risk. Pediatric eyes with noninfectious uveitis should be followed up closely for IOP elevation, especially when strong risk factors such as the use of local corticosteroids and contralateral IOP elevation are present.

Turalba A, Payal AR, Gonzalez-Gonzalez LA, Cakiner-Egilmez T, Chomsky AS, Vollman DE, Baze EF, Lawrence M, Daly MK. Cataract Surgery Outcomes in Glaucomatous Eyes: Results From the Veterans Affairs Ophthalmic Surgery Outcomes Data Project. Am J Ophthalmol 2015;160(4):693-701.e1.Abstract

PURPOSE: To compare visual acuity outcomes, vision-related quality of life, and complications related to cataract surgery in eyes with and without glaucoma. DESIGN: Retrospective cohort study. METHODS: Cataract surgery outcomes in cases with and without glaucoma from the Veterans Affairs Ophthalmic Surgical Outcomes Data Project were compared. RESULTS: We identified 608 glaucoma cases and 4306 controls undergoing planned cataract surgery alone. After adjusting for age, pseudoexfoliation, small pupil, prior ocular surgery, and anterior chamber depth, we found that glaucoma cases were more likely to have posterior capsular tear with vitrectomy (odds ratio [OR] 1.8, P = .03) and sulcus intraocular lens placement (OR 1.65, P = .03) during cataract surgery. Glaucoma cases were more likely to have postoperative inflammation (OR 1.73, P < .0001), prolonged elevated intraocular pressure (OR 2.96, P = .0003), and additional surgery within 30 days (OR 1.92, P = .03). Mean best-corrected visual acuity (BCVA) and Visual Function Questionnaire (VFQ) scores significantly improved after cataract surgery in both groups (P < .0001), but there were larger improvements in BCVA (P = .01) and VFQ composite scores (P < .0001) in the nonglaucoma vs the glaucoma group. A total of 3621 nonglaucoma cases (94.1%) had postoperative BCVA 20/40 or better, compared to 466 glaucoma cases (89.6%) (P = .0003). CONCLUSIONS: Eyes with glaucoma are at increased risk for complications and have more modest visual outcomes after cataract surgery compared to eyes without glaucoma. Despite this, glaucoma patients still experience significant improvement in vision-related outcomes after cataract extraction. Further study is needed to explore potential factors that influence cataract surgery outcomes in glaucomatous eyes.

Grassi CM, Cruzat A, Taniguchi EV, Crnej A, Colby KA, Dohlman CH, Chodosh J. Periprosthetic Tissue Loss in Patients With Idiopathic Vitreous Inflammation After the Boston Keratoprosthesis. Cornea 2015;34(11):1378-82.Abstract

PURPOSE: Idiopathic vitritis is a poorly understood complication after Boston keratoprosthesis surgery with unclear etiology. We sought to determine whether an association exists between periprosthetic corneal tissue loss and the development of idiopathic vitritis in keratoprosthesis recipients. METHODS: Thirteen Boston type I keratoprosthesis recipient eyes with a history of idiopathic vitritis and 34 type I keratoprosthesis recipient eyes with no history of idiopathic vitritis underwent anterior segment optical coherence tomography (AS-OCT) at a median time postoperatively of 2.4 years versus 1.9 years (range, 0.5-14.2 vs. 0.1-13.6 years), respectively. Areas of corneal graft tissue loss ("gaps") around the keratoprosthesis stem were identified and analyzed by 2 masked observers. The difference in the presence, number, and size of gaps was compared between cases and controls. RESULTS: A periprosthetic gap was identified more commonly in idiopathic vitritis cases than in controls on AS-OCT (11/13, 86% vs. 11/34, 33.3%, P < 0.001). The number of gaps between cases and controls was also significantly different (2.6 ± 1.6 vs. 0.5 ± 0.8, P < 0.001), but not the estimated gap area (0.056 ± 0.049 mm vs. 0.039 ± 0.025 mm, P = 0.22). CONCLUSIONS: A significantly higher proportion of keratoprosthesis recipient eyes with idiopathic vitritis had corneal tissue loss around the keratoprosthesis stem than did controls. Tissue loss could serve as an entry point for debris or bacterial components, triggering idiopathic vitritis. Our study underscores the utility of AS-OCT imaging in the postoperative management of keratoprosthesis patients.

Joshi PK, Esko T, Mattsson H, Eklund N, Gandin I, Nutile T, Jackson AU, Schurmann C, Smith AV, Zhang W, Okada Y, Stančáková A, Faul JD, Zhao W, Bartz TM, Concas MP, Franceschini N, Enroth S, Vitart V, Trompet S, Guo X, Chasman DI, O'Connel JR, Corre T, Nongmaithem SS, Chen Y, Mangino M, Ruggiero D, Traglia M, Farmaki A-E, Kacprowski T, Bjonnes A, van der Spek A, Wu Y, Giri AK, Yanek LR, Wang L, Hofer E, Rietveld CA, McLeod O, Cornelis MC, Pattaro C, Verweij N, Baumbach C, Abdellaoui A, Warren HR, Vuckovic D, Mei H, Bouchard C, Perry JRB, Cappellani S, Mirza SS, Benton MC, Broeckel U, Medland SE, Lind PA, Malerba G, Drong A, Yengo L, Bielak LF, Zhi D, van der Most PJ, Shriner D, Mägi R, Hemani G, Karaderi T, Wang Z, Liu T, Demuth I, Zhao JH, Meng W, Lataniotis L, van der Laan SW, Bradfield JP, Wood AR, Bonnefond A, Ahluwalia TS, Hall LM, Salvi E, Yazar S, Carstensen L, de Haan HG, Abney M, Afzal U, Allison MA, Amin N, Asselbergs FW, Bakker SJL, Barr GR, Baumeister SE, Benjamin DJ, Bergmann S, Boerwinkle E, Bottinger EP, Campbell A, Chakravarti A, Chan Y, Chanock SJ, Chen C, Chen IY-D, Collins FS, Connell J, Correa A, Cupples AL, Smith GD, Davies G, Dörr M, Ehret G, Ellis SB, Feenstra B, Feitosa MF, Ford I, Fox CS, Frayling TM, Friedrich N, Geller F, Scotland G, Gillham-Nasenya I, Gottesman O, Graff M, Grodstein F, Gu C, Haley C, Hammond CJ, Harris SE, Harris TB, Hastie ND, Heard-Costa NL, Heikkilä K, Hocking LJ, Homuth G, Hottenga J-J, Huang J, Huffman JE, Hysi PG, Ikram AM, Ingelsson E, Joensuu A, Johansson Å, Jousilahti P, Jukema WJ, Kähönen M, Kamatani Y, Kanoni S, Kerr SM, Khan NM, Koellinger P, Koistinen HA, Kooner MK, Kubo M, Kuusisto J, Lahti J, Launer LJ, Lea RA, Lehne B, Lehtimäki T, Liewald DCM, Lind L, Loh M, Lokki M-L, London SJ, Loomis SJ, Loukola A, Lu Y, Lumley T, Lundqvist A, Männistö S, Marques-Vidal P, Masciullo C, Matchan A, Mathias RA, Matsuda K, Meigs JB, Meisinger C, Meitinger T, Menni C, Mentch FD, Mihailov E, Milani L, Montasser ME, Montgomery GW, Morrison A, Myers RH, Nadukuru R, Navarro P, Nelis M, Nieminen MS, Nolte IM, O'Connor GT, Ogunniyi A, Padmanabhan S, Palmas WR, Pankow JS, Patarcic I, Pavani F, Peyser PA, Pietilainen K, Poulter N, Prokopenko I, Ralhan S, Redmond P, Rich SS, Rissanen H, Robino A, Rose LM, Rose R, Sala C, Salako B, Salomaa V, Sarin A-P, Saxena R, Schmidt H, Scott LJ, Scott WR, Sennblad B, Seshadri S, Sever P, Shrestha S, Smith BH, Smith JA, Soranzo N, Sotoodehnia N, Southam L, Stanton AV, Stathopoulou MG, Strauch K, Strawbridge RJ, Suderman MJ, Tandon N, Tang S-T, Taylor KD, Tayo BO, Töglhofer AM, Tomaszewski M, Tšernikova N, Tuomilehto J, Uitterlinden AG, Vaidya D, van Hylckama Vlieg A, van Setten J, Vasankari T, Vedantam S, Vlachopoulou E, Vozzi D, Vuoksimaa E, Waldenberger M, Ware EB, Wentworth-Shields W, Whitfield JB, Wild S, Willemsen G, Yajnik CS, Yao J, Zaza G, Zhu X, Zhu X, Salem RM, Melbye M, Bisgaard H, Samani NJ, Cusi D, Mackey DA, Cooper RS, Froguel P, Pasterkamp G, Grant SFA, Hakonarson H, Ferrucci L, Scott RA, Morris AD, Palmer CNA, Dedoussis G, Deloukas P, Bertram L, Lindenberger U, Berndt SI, Lindgren CM, Timpson NJ, Tönjes A, Munroe PB, Sørensen TIA, Rotimi CN, Arnett DK, Oldehinkel AJ, Kardia SLR, Balkau B, Gambaro G, Morris AP, Eriksson JG, Wright MJ, Martin NG, Hunt SC, Starr JM, Deary IJ, Griffiths LR, Tiemeier H, Pirastu N, Kaprio J, Wareham NJ, Pérusse L, Wilson JG, Girotto G, Caulfield MJ, Raitakari O, Boomsma DI, Gieger C, van der Harst P, Hicks AA, Kraft P, Sinisalo J, Knekt P, Johannesson M, Magnusson PKE, Hamsten A, Schmidt R, Borecki IB, Vartiainen E, Becker DM, Bharadwaj D, Mohlke KL, Boehnke M, van Duijn CM, Sanghera DK, Teumer A, Zeggini E, Metspalu A, Gasparini P, Ulivi S, Ober C, Toniolo D, Rudan I, Porteous DJ, Ciullo M, Spector TD, Hayward C, Dupuis J, Loos RJF, Wright AF, Chandak GR, Vollenweider P, Shuldiner AR, Ridker PM, Rotter JI, Sattar N, Gyllensten U, North KE, Pirastu M, Psaty BM, Weir DR, Laakso M, Gudnason V, Takahashi A, Chambers JC, Kooner JS, Strachan DP, Campbell H, Hirschhorn JN, Perola M, Polašek O, Wilson JF. Directional dominance on stature and cognition indiverse human populations. Nature 2015;523(7561):459-62.Abstract

Homozygosity has long been associated with rare, often devastating, Mendelian disorders, and Darwin was one of the first to recognize that inbreeding reduces evolutionary fitness. However, the effect of the more distant parental relatedness that is common in modern human populations is less well understood. Genomic data now allow us to investigate the effects of homozygosity on traits of public health importance by observing contiguous homozygous segments (runs of homozygosity), which are inferred to be homozygous along their complete length. Given the low levels of genome-wide homozygosity prevalent in most human populations, information is required on very large numbers of people to provide sufficient power. Here we use runs of homozygosity to study 16 health-related quantitative traits in 354,224 individuals from 102 cohorts, and find statistically significant associations between summed runs of homozygosity and four complex traits: height, forced expiratory lung volume in one second, general cognitive ability and educational attainment (P < 1 × 10(-300), 2.1 × 10(-6), 2.5 × 10(-10) and 1.8 × 10(-10), respectively). In each case, increased homozygosity was associated with decreased trait value, equivalent to the offspring of first cousins being 1.2 cm shorter and having 10 months' less education. Similar effect sizes were found across four continental groups and populations with different degrees of genome-wide homozygosity, providing evidence that homozygosity, rather than confounding, directly contributes to phenotypic variance. Contrary to earlier reports in substantially smaller samples, no evidence was seen of an influence of genome-wide homozygosity on blood pressure and low density lipoprotein cholesterol, or ten other cardio-metabolic traits. Since directional dominance is predicted for traits under directional evolutionary selection, this study provides evidence that increased stature and cognitive function have been positively selected in human evolution, whereas many important risk factors for late-onset complex diseases may not have been.