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Meta-Analysis
. 2011;6(8):e22103.
doi: 10.1371/journal.pone.0022103. Epub 2011 Aug 10.

Ethnic and mouse strain differences in central corneal thickness and association with pigmentation phenotype

David P Dimasi  1 , Alex W Hewitt, Kenneth Kagame, Sam Ruvama, Ludovica Tindyebwa, Bastien Llamas, Kirsty A Kirk, Paul Mitchell, Kathryn P Burdon, Jamie E Craig
Affiliations
Meta-Analysis

Ethnic and mouse strain differences in central corneal thickness and association with pigmentation phenotype

David P Dimasi et al. PLoS One. 2011.

Abstract

The cornea is a transparent structure that permits the refraction of light into the eye. Evidence from a range of studies indicates that central corneal thickness (CCT) is strongly genetically determined. Support for a genetic component comes from data showing significant variation in CCT between different human ethnic groups. Interestingly, these studies also appear to show that skin pigmentation may influence CCT. To validate these observations, we undertook the first analysis of CCT in an oculocutaneous albinism (OCA) and Ugandan cohort, populations with distinct skin pigmentation phenotypes. There was a significant difference in the mean CCT of the OCA, Ugandan and Australian-Caucasian cohorts (Ugandan: 517.3±37 µm; Caucasian: 539.7±32.8 µm, OCA: 563.3±37.2 µm; p<0.001). A meta-analysis of 53 studies investigating the CCT of different ethnic groups was then performed and demonstrated that darker skin pigmentation is associated with a thinner CCT (p<0.001). To further verify these observations, we measured CCT in 13 different inbred mouse strains and found a significant difference between the albino and pigmented strains (p = 0.008). Specific mutations within the melanin synthesis pathway were then investigated in mice for an association with CCT. Significant differences between mutant and wild type strains were seen with the nonagouti (p<0.001), myosin VA (p<0.001), tyrosinase (p = 0.025) and tyrosinase related protein (p = 0.001) genes. These findings provide support for our hypothesis that pigmentation is associated with CCT and identifies pigment-related genes as candidates for developmental determination of a non-pigmented structure.

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Conflict of interest statement

Competing Interests: The authors wish to declare that Pfizer Australia, who provided partial funding, was not involved in the study design, collection, analysis and interpretation of data, writing of the paper, and/or decision to submit for publication.

Figures

Figure 1
Figure 1. Flow chart detailing the selection process for articles included in the meta-analysis.
Figure 2
Figure 2. Global skin colour distribution of native populations.
The colours on the map are based on the 36-tone chromatic scale devised by Austrian anthropologist Felix von Luschan to assess the unexposed skin of human populations. The higher numbers represent darker skin colour. Original data compiled by Biasutti 1941.
Figure 3
Figure 3. Graphical representation of the human CCT meta-analysis results.
(A) Mean CCT of each ethnic group. Colours indicate tone of skin pigmentation according to the chart devised by Biasutti, 1941 (see Figure 1) (B) Mean CCT of the Dark Skin (524.6±33.6 µm, n = 16,472) and Light Skin (548.4±34.1 µm, n = 14,152) groups based on the skin colour of the ethnic groups in Figure 1A. There was a significant difference between the groups (p<0.001).
Figure 4
Figure 4. Graphical representation of CCT measurements conducted on the inbred mouse strains.
(A) Mean CCT and coat colour of the each individual strain. There was a significant difference in mean CCT of each strain (p<0.001). The colours of the bars represent the coat pigmentation of the animals. Error bars indicate standard deviation. (B) Mean CCT of the Pigment (78.3±8.8 µm, n = 53) and Albino (83.5±11.1 µm, n = 79) groups based on the coat colour of the animals in Figure 3A. Error bars indicate standard deviation. There was a significant difference between the groups (p = 0.008).
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References

    1. Gordon MO, Beiser JA, Brandt JD, Heuer DK, Higginbotham EJ, et al. The Ocular Hypertension Treatment Study: baseline factors that predict the onset of primary open-angle glaucoma. Arch Ophthalmol. 2002;120:714–720; discussion 829–730. - PubMed
    1. Miglior S, Pfeiffer N, Torri V, Zeyen T, Cunha-Vaz J, et al. Predictive factors for open-angle glaucoma among patients with ocular hypertension in the European Glaucoma Prevention Study. Ophthalmology. 2007;114:3–9. - PubMed
    1. Francis BA, Varma R, Chopra V, Lai MY, Shtir C, et al. Intraocular pressure, central corneal thickness, and prevalence of open-angle glaucoma: the Los Angeles Latino Eye Study. Am J Ophthalmol. 2008;146:741–746. - PMC - PubMed
    1. Brandt JD, Casuso LA, Budenz DL. Markedly increased central corneal thickness: an unrecognized finding in congenital aniridia. Am J Ophthalmol. 2004;137:348–350. - PubMed
    1. Whitson JT, Liang C, Godfrey DG, Petroll WM, Cavanagh HD, et al. Central corneal thickness in patients with congenital aniridia. Eye Contact Lens. 2005;31:221–224. - PubMed

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