Mapping of the gene for X-linked amelogenesis imperfecta by linkage analysis.
X-linked Amelogenesis imperfecta (AI) is a genetic disorder affecting the formation of enamel. In the present study two families, one with X-linked dominant and one with X-linked recessive AI, were studied by linkage analysis. Eleven cloned RFLP markers of known regional location were used. Evidence was obtained for linkage between the AI locus and the marker p782, defining the locus DXS85 at Xp22, by using two-point analysis. No recombination was scored between these two loci in 15 informative meioses, and a peak lod score (Zmax) of 4.45 was calculated at zero recombination fraction. Recombination was observed between the more distal locus DXS89 and AI, giving a peak lod score of 3.41 at a recombination fraction of .09. Recombination was also observed between the AI locus and the more proximal loci DXS43 and DXS41 (Zmax = 0.09 at theta max = 0.31 and Zmax = 0.61 at theta max = 0.28, respectively). Absence of linkage was observed between the AI locus and seven other loci, located proximal to DXS41 or on the long arm of the X chromosome. On the basis of two-point linkage analysis and analysis of crossover events, we propose the following order of loci at Xp22: DXS89-(AI, DXS85)-DXS43-DXS41-Xcen.
Lagerström
M
M
Department of Medical Genetics, University of Uppsala Biomedical Center, Sweden.
Dahl
N
N
Iselius
L
L
Bäckman
B
B
Pettersson
U
U
D000567:Amelogenesis Imperfecta / Q000235:genetics*; D015342:DNA Probes; D005260:Female; D008040:Genetic Linkage; D005819:Genetic Markers; D006801:Humans; D008297:Male; D012150:Polymorphism, Restriction Fragment Length; D011995:Recombination, Genetic; D015183:Restriction Mapping; D014960:X Chromosome
D015342:DNA Probes; D005819:Genetic Markers