Chromosomes 4q28.3 and 7q31.2 as new susceptibility loci for comitant strabismus.
OBJECTIVE
This study was designed to localize chromosomal susceptibility loci for comitant strabismus among Japanese families by genome-wide linkage analyses.


METHODS
Fifty-five Japanese families, with at least two members with comitant strabismus (esotropia and/or exotropia), were subject to full ophthalmic examination, careful ocular history, and review of medical records. DNA was obtained and genotyping was performed with PCR amplification of 400 microsatellite markers. Parametric and nonparametric linkage (NPL) analyses scores were calculated. Linkage analysis was performed for the whole set of families (55 families), and then a second analysis was performed for two subgroups with the phenotypes, esotropia and exotropia.


RESULTS
A multipoint parametric heterogeneity logarithm of the odds (HLOD) score of 3.62 was obtained at marker D4S1575 under a dominant model, with a NPL score of 2.68 (P=0.001). Testing under different penetrances and disease allele frequencies revealed two other susceptibility loci at 7q31.2 under a recessive model (HLOD scores=3.93 and 4.40 at 125.2 cM and 107.28 cM, respectively). Analysis of the subgroups revealed new susceptibility loci for esotropia; one locus at 8q24.21 is worthy of further investigation.


CONCLUSIONS
This study suggests multiple susceptibility loci for comitant strabismus. The loci at chromosomes 4q28.3 and 7q31.2 show a significant evidence of linkage.
Shaaban
Sherin
S
Department of Ophthalmology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama City, Japan.
Matsuo
Toshihiko
T
Fujiwara
Hirotake
H
Itoshima
Emi
E
Furuse
Takashi
T
Hasebe
Satoshi
S
Zhang
Qingrun
Q
Ott
Jurg
J
Ohtsuki
Hiroshi
H
D044466:Asian People / Q000235:genetics; D002874:Chromosome Mapping; D002894:Chromosomes, Human, Pair 4 / Q000235:genetics*; D002897:Chromosomes, Human, Pair 7 / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D015894:Genome, Human; D005838:Genotype; D006801:Humans; D008126:Lod Score; D008297:Male; D008957:Models, Genetic; D010375:Pedigree; D013285:Strabismus / Q000235:genetics*