TY - JOUR

T1 - Heritability of Retinal Vascular Fractals

T2 - A Twin Study

AU - Vergmann, Anna Stage

AU - Broe, Rebecca

AU - Kessel, Line

AU - Hougaard, Jesper Leth

AU - Möller, Sören

AU - Kyvik, Kirsten Ohm

AU - Larsen, Michael

AU - Munch, Inger Christine

AU - Grauslund, Jakob

PY - 2017/8

Y1 - 2017/8

N2 - Purpose: To determine the genetic contribution to the pattern of retinal vascular branching expressed by its fractal dimension.Methods: This was a cross-sectional study of 50 monozygotic and 49 dizygotic, same-sex twin pairs aged 20 to 46 years. In 50°, disc-centered fundus photographs, the retinal vascular fractal dimension was measured using the box-counting method and compared within monozygotic and dizygotic twin pairs using Pearson correlation coefficients. Falconer's formula and quantitative genetic models were used to determine the genetic component of variation.Results: The mean fractal dimension did not differ statistically significantly between monozygotic and dizygotic twin pairs (1.505 vs. 1.495, P = 0.06), supporting that the study population was suitable for quantitative analysis of heritability. The intrapair correlation was markedly higher (0.505, P = 0.0002) in monozygotic twins than in dizygotic twins (0.108, P = 0.46), corresponding to a heritability h2 for the fractal dimension of 0.79. In quantitative genetic models, dominant genetic effects explained 54% of the variation and 46% was individually environmentally determined.Conclusions: In young adult twins, the branching pattern of the retinal vessels demonstrated a higher structural similarity in monozygotic than in dizygotic twin pairs. The retinal vascular fractal dimension was mainly determined by genetic factors, which accounted for 54% of the variation. The genetically predetermination of the retinal vasculature may affect the retinal response to potential vascular disease in later life.

AB - Purpose: To determine the genetic contribution to the pattern of retinal vascular branching expressed by its fractal dimension.Methods: This was a cross-sectional study of 50 monozygotic and 49 dizygotic, same-sex twin pairs aged 20 to 46 years. In 50°, disc-centered fundus photographs, the retinal vascular fractal dimension was measured using the box-counting method and compared within monozygotic and dizygotic twin pairs using Pearson correlation coefficients. Falconer's formula and quantitative genetic models were used to determine the genetic component of variation.Results: The mean fractal dimension did not differ statistically significantly between monozygotic and dizygotic twin pairs (1.505 vs. 1.495, P = 0.06), supporting that the study population was suitable for quantitative analysis of heritability. The intrapair correlation was markedly higher (0.505, P = 0.0002) in monozygotic twins than in dizygotic twins (0.108, P = 0.46), corresponding to a heritability h2 for the fractal dimension of 0.79. In quantitative genetic models, dominant genetic effects explained 54% of the variation and 46% was individually environmentally determined.Conclusions: In young adult twins, the branching pattern of the retinal vessels demonstrated a higher structural similarity in monozygotic than in dizygotic twin pairs. The retinal vascular fractal dimension was mainly determined by genetic factors, which accounted for 54% of the variation. The genetically predetermination of the retinal vasculature may affect the retinal response to potential vascular disease in later life.

KW - Adult

KW - Cross-Sectional Studies

KW - Female

KW - Fractals

KW - Humans

KW - Male

KW - Middle Aged

KW - Quantitative Trait, Heritable

KW - Retinal Vessels

KW - Surveys and Questionnaires

KW - Twins, Dizygotic

KW - Twins, Monozygotic

KW - Young Adult

KW - Journal Article

KW - Twin Study

U2 - 10.1167/iovs.17-22072

DO - 10.1167/iovs.17-22072

M3 - Journal article

C2 - 28800646

VL - 58

SP - 3997

EP - 4002

JO - Investigative Ophthalmology & Visual Science

JF - Investigative Ophthalmology & Visual Science

SN - 0146-0404

IS - 10

ER -