Developmental Coordination Disorder: What Can We Learn From Recombinant Inbred Mice Using Motor Learning Tasks and Quantitative Trait Locus Analysis

Developmental Coordination Disorder (DCD) is a motor skills disorder that affects 5-6% of all school-aged children. There is an indication that DCD has an underlying genetic component due to its high heritability. Therefore, we we have explored the use of a recombinant inbred family of mice known as the BXD panel to understand the genetic basis of complex traits (i.e., motor learning) through identification of Quantitative Trait Loci (QTLs). The overall aim of this study was to utilize the QTL approach to evaluate the genome-to-phenome correlation in BXD strains of mice in order to to better understanding the human presentation of DCD. Results in this current study indicate there is a spectrum of motor learning in the pre-selected BXD strains of mice with a spectrum between high and low learning capabilities. Five lines - BXD15, BXD27, BXD28, BXD75, and BXD86 - exhibited the most DCD-like phenotype, when compared to other BXD lines of interest. The results indicate that BXD15 and BXD75 struggled primarily with gross motor skills, BXD28 primarily had difficulties with fine motor skills, and BXD27 and BXD28 lines struggled with both fine and gross motor skills. The functional roles of significant QTL genes were assessed in relation to DCD-like behavior. Only Rab3a (Ras-related protein Rab-3A) emerged as a best candidate gene for the horizontal ladder rung task. This gene is found to be associated with brain and skeletal muscle development. This is the first study to specifically examine the genetic linkage of DCD using BXD lines of mice.