Dyslexia and chromosome 15 heteromorphism: negative lod score in a Danish material

From a large Danish material of random families we selected families with dyslexia as reported by the families themselves and as recorded by a dyslexia institute. Among five "backcross families" studied for chromosome 15 polymorphisms we found only negative lod scores, and at theta = 0.10 a negative score of -3.42; i.e., in our material we did not find any confirmation of the indication of linkage between dyslexia and a chromosome 15 polymorphism found in part of their material by Smith et al. (1983, 1986).