Quantitative Trait Locus for Reading Disability on Chromosome 6

TLDR

Interval mapping of sib‑pair data identified a quantitative trait locus on chromosome 6. The QTL was localized to 6p21.3 within the HLA complex, replicated in twin pairs, and defined to a 2‑cM region with chi‑square values of 16.73 (P = 0.0002) and 27.35 (P < 0.00001) in extreme cases.

Abstract

Interval mapping of data from two independent samples of sib pairs, at least one member of whom was reading disabled, revealed evidence for a quantitative trait locus (QTL) on chromosome 6. Results obtained from analyses of reading performance from 114 sib pairs genotyped for DNA markers localized the QTL to 6p21.3. Analyses of corresponding data from an independent sample of 50 dizygotic twin pairs provided evidence for linkage to the same region. In combination, the replicate samples yielded a chi 2 value of 16.73 (P = 0.0002). Examination of twin and kindred siblings with more extreme deficits in reading performance yielded even stronger evidence for a QTL (chi 2 = 27.35, P < 0.00001). The position of the QTL was narrowly defined with a 100:1 confidence interval to a 2-centimorgan region within the human leukocyte antigen complex.