Genetic dissection of myopia: evidence for linkage of ocular axial length to chromosome 5q.
OBJECTIVE
To estimate heritability and locate quantitative trait loci influencing axial length.


METHODS
Classic twin study of monozygotic and dizygotic twins reared together.


METHODS
Eight hundred ninety-three individuals from 460 families were recruited through the Twin Eye Study in Tasmania and the Brisbane Adolescent Twin Study (BATS) and had ocular axial length measured.


METHODS
Structural equation modeling on the entire sample was used to estimate genetic and environmental components of variation in axial length. Analysis of existing microsatellite marker genomewide linkage scan data was performed on 318 individuals from 142 BATS families.


METHODS
Ocular axial length.


RESULTS
The heritability estimate for axial length, adjusted for age and sex, in the full sample was 0.81. The highest multipoint logarithm of the odds (LOD) score observed was 3.40 (genomewide P = 0.0004), on chromosome 5q (at 98 centimorgans [cM]). Additional regions with suggestive multipoint LOD scores were also identified on chromosome 6 (LOD scores, 2.13 at 76 cM and 2.05 at 83 cM), chromosome 10 (LOD score, 2.03 at 131 cM), and chromosome 14 (LOD score, 2.84 at 97 cM).


CONCLUSIONS
Axial length, a major endophenotype for refractive error, is highly heritable and is likely to be influenced by one or more genes on the long arm of chromosome 5.
Zhu
Gu
G
Genetic Epidemiology Unit, Queensland Institute of Medical Research, Brisbane, Australia. D.Mackey@utas.edu.au
Hewitt
Alex W
AW
Ruddle
Jonathan B
JB
Kearns
Lisa S
LS
Brown
Shayne A
SA
Mackinnon
Jane R
JR
Chen
Christine Y
CY
Hammond
Christopher J
CJ
Craig
Jamie E
JE
Montgomery
Grant W
GW
Martin
Nicholas G
NG
Mackey
David A
DA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D002895:Chromosomes, Human, Pair 5 / Q000235:genetics*; D004200:Diseases in Twins / Q000235:genetics*; D005123:Eye / Q000473:pathology*; D005260:Female; D008040:Genetic Linkage; D005838:Genotype; D006801:Humans; D008126:Lod Score; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D009216:Myopia / Q000235:genetics*; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic