A condition in which reading ability is significantly below the norm in relation to chronological age and overall intellectual potential.

Also referred to as reading disability, reading difficulty, and dyslexia, developmental reading disorder is the most commonly diagnosed learning disability in the United States. Estimates of its prevalence vary widely, ranging from 4% of children—the figure given by the American Psychiatric Association's Diagnostic and Statistical Manual—to 20%, the figure given by a 1995 study directed by Sally E. Shaywitz of Yale University....