Hyperlexia and dyslexia: A family study.

The condition of hyperlexia, often associated with autism, is a rare disorder in which children read words precociously but show little comprehension, markedly poor language, behavioral, and interpersonal skills. The relationship of hyperlexia and dyslexia has never been investigated, although suggestions have been made that the two conditions may be related. In light of current research on familial factors in autism, language disorder, dyslexia, and, recently, hyperlexia, this study investigated family histories of twelve hyperlexic children in regard to language, reading, writing, spelling, and other learning problems, handedness, and presence of allergies. Results suggest a distinct familial tendency to disorders of language, reading, writing, and spelling in male relatives, along with an unusually high instance of nonleft-handedness. Allergy information is inconclusive. Descriptive data are presented, and the relationship of symptomatology in hyperlexia and dyslexia is described and discussed. It is suggested that hyperlexia may represent a point of convergence of several genetically-linked developmental disorders.