Investigation of the DCDC2 intron 2 deletion/compound short tandem repeat polymorphism in a large German dyslexia sample.
Dyslexia is a complex disorder manifested by difficulties in learning to read and spell despite conventional instruction, adequate intelligence and sociocultural opportunity. It is among the most common neurodevelopmental disorders with a prevalence of 5-12%. The dyslexia susceptibility locus 2 on chromosome 6p21-p22 is one of the best-replicated linkage regions in dyslexia. On the basis of systematic linkage disequilibrium studies, the doublecortin domain containing protein 2 gene (DCDC2) was identified as a strong candidate gene in this region. Data from a US study have suggested a complex deletion/compound short tandem repeat (STR) polymorphism in intron 2 of DCDC2 as the causative mutation. In this study, we analyzed this polymorphism in 396 German dyslexia trios which included 376 trios previously providing strong support for the DCDC2 locus. We observed no significant deviation from random transmission, neither for the deletion nor for the alleles of the compound STR. We also did not find the deletion or any of the STR alleles to be in linkage disequilibrium with the 2-marker haplotype, which was associated with dyslexia in our sample. We thus conclude that the causative variant/s in DCDC2 conferring susceptibility to dyslexia in our sample remain/s to be identified.
Ludwig
Kerstin U
KU
Department of Genomics, Life and Brain Center, University of Bonn, Bonn, Germany.
Schumacher
Johannes
J
Schulte-Körne
Gerd
G
König
Inke R
IR
Warnke
Andreas
A
Plume
Ellen
E
Anthoni
Heidi
H
Peyrard-Janvid
Myriam
M
Meng
Haiying
H
Ziegler
Andreas
A
Remschmidt
Helmut
H
Kere
Juha
J
Gruen
Jeffrey R
JR
Müller-Myhsok
Bertram
B
Nöthen
Markus M
MM
Hoffmann
Per
P
D002896:Chromosomes, Human, Pair 6; D004410:Dyslexia / Q000235:genetics*; D017353:Gene Deletion; D005858:Germany; D006801:Humans; D007438:Introns; D015810:Linkage Disequilibrium; D018895:Microsatellite Repeats; D008869:Microtubule-Associated Proteins / Q000235:genetics*; D011110:Polymorphism, Genetic
C510451:DCDC2 protein, human; D008869:Microtubule-Associated Proteins