Abstract
Purpose::
We examined whether the 7p22.1 region reported in the United States would be also a candidate locus for our Japanese pedigrees with strabismus.
Methods::
According to the method approved by the Ethical Committee of Okayama University Medical School, genomic DNA was extracted from blood samples obtained from strabismic patients and their family members. Using an ABI310 Genetic AnalyzerTM, genotypes were determined with microsatellite markers in the 7p22.1 region. Non-parametric linkage (NPL) scores were calculated by genetic statistical analysis with a computer program (GenehunterTM), and the values were compared with those reported in the American pedigrees.
Results::
Blood samples were collected from members of 52 pedigrees with family history of exotropia or esotropia. In 52 pedigrees, the NPL scores (p values) were 0.44 (0.31) at D7S531, 0.50 (0.29) at D7S517, 1.71 (0.03) at D7S513, 1.24 (0.09) at D7S507, 0.82 (0.18) at D7S493, and 1.23 (0.42) at D7S516, indicating probable linkage of this chromosomal locus with strabismus in the 52 Japanese pedigrees. Twenty (38%) of the 52 pedigrees showed an NPL score over 1.00 in the 7p22.1 region. We focused on these pedigrees as a subgroup and calculated the NPL scores. In the subgroup of 20 pedigrees, NPL scores (p values) were 4.36(3.43x10-6) at D7S531, 4.68(5.77x10-7) at D7S517, 4.92(9.88x10-8) at D7S513, 4.66(5.77x10-7) at D7S507, 4.00(1.70x10-5) at D7S493, and 3.47(1.88x10-4) at D7S516, indicating significant linkage of this chromosomal locus with strabismus in these 20 Japanese pedigrees.
Conclusions::
The results suggested multiple strabismus-related loci in the Japanese pedigrees and one strabismus-related locus located in the 7p22.1 region.
Keywords: strabismus • gene mapping • linkage analysis