RT Journal Article SR Electronic T1 Linkage studies in dominant optic atrophy, Kjer type: possible evidence for heterogeneity. JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 967 OP 972 DO 10.1136/jmg.34.12.967 VO 34 IS 12 A1 Seller, M J A1 Behnam, J T A1 Lewis, C M A1 Johnston, R L A1 Burdon, M A A1 Spalton, D J YR 1997 UL http://jmg.bmj.com/content/34/12/967.abstract AB Dominant optic atrophy, Kjer type, is an autosomal dominant disorder causing progressive loss of visual acuity and colour vision from early childhood. The gene (OPA1) has variable expressivity, a penetrance of 0.98, and the locus has been localised to 3q28-29. We have genotyped nine British families with the disease using 12 polymorphic microsatellite markers from this region. Linkage and haplotype analysis shows the OPA1 gene to be located in a 2.3 cM interval between markers D3S1601 and D3S2748. One family showed no evidence of linkage with the chromosome 3 markers, suggesting for the first time that locus heterogeneity for this disease may exist, although exclusion for linkage is based on unaffected subjects. In addition, analysis of recombinants has enabled us to order the 12 markers along chromosome 3.