title: A second locus for familial high myopia maps to chromosome 12q.
abstract: Myopia, or nearsightedness, is the most common eye disorder worldwide. "Pathologic" high myopia, or myopia of <=-6.00 diopters, predisposes individuals to retinal detachment, macular degeneration, cataract, or glaucoma. A locus for autosomal dominant pathologic high myopia has been mapped to 18p11.31. We now report significant linkage of high myopia to a second locus at the 12q21-23 region in a large German/Italian family. The family had no clinical evidence of connective-tissue abnormalities or glaucoma. The average age at diagnosis of myopia was 5.9 years. The average spherical-component refractive error for the affected individuals was -9.47 diopters. Markers flanking or intragenic to the genes for the 18p locus, Stickler syndromes type I and II (12q13.1-q13.3 and 6p21.3), Marfan syndrome (15q21.1), and juvenile glaucoma (chromosome 1q21-q31) showed no linkage to the myopia in this family. The maximum LOD score with two-point linkage analysis in this pedigree was 3.85 at a recombination fraction of .0010, for markers D12S1706 and D12S327. Recombination events identified markers D12S1684 and D12S1605 as flanking markers that define a 30.1-cM interval on chromosome 12q21-23, for the second myopia gene. These results confirm genetic heterogeneity of myopia. The identification of this gene may provide insight into the pathophysiology of myopia and eye development.
authors.affiliation: Department of Opthalmology, Division of Epidemiology, University of Minnesota, Minneapolis, MN, USA. young061@gold.tc.umn.edu
authors.forename: T L
authors.initials: TL
authors.lastname: Young
authors.forename: S M
authors.initials: SM
authors.lastname: Ronan
authors.forename: A B
authors.initials: AB
authors.lastname: Alvear
authors.forename: S C
authors.initials: SC
authors.lastname: Wildenberg
authors.forename: W S
authors.initials: WS
authors.lastname: Oetting
authors.forename: L D
authors.initials: LD
authors.lastname: Atwood
authors.forename: D J
authors.initials: DJ
authors.lastname: Wilkin
authors.forename: R A
authors.initials: RA
authors.lastname: King
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D002648:Child; D002675:Child, Preschool; D002874:Chromosome Mapping; D002881:Chromosomes, Human, Pair 12; D005260:Female; D005819:Genetic Markers; D005858:Germany / Q000208:ethnology; D005901:Glaucoma / Q000235:genetics; D006801:Humans; D007438:Introns; D007558:Italy / Q000208:ethnology; D008297:Male; D008382:Marfan Syndrome / Q000235:genetics; D008875:Middle Aged; D009216:Myopia / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D010375:Pedigree; D011995:Recombination, Genetic; D014481:United States
chemical_list: D005819:Genetic Markers