Family History of Dyslexia

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In their article, Lasnick et al. (2022) provide an overview of the research into the link between the risk of developmental dyslexia and a family history of dyslexia and discuss the potential of family history questionnaires as a tool for early screening. The following is a brief summary of their findings.

It is generally agreed that developmental dyslexia is a specific learning disability that is neurobiological in nature. A large proportion of children diagnosed with dyslexia can improve their reading ability with explicit, systematic, evidence-based intervention. The earlier this intervention is commenced the better the outcome.

The research shows that dyslexia runs in families, partly due to shared environmental factors, but also because there is a distinctive inherited genetic component. In fact, 34-54% of children with a family history of dyslexia show characteristics of dyslexia, even in homes with enriched literacy environments. In comparison, only 8-16% of children without a family history of dyslexia develop dyslexia symptoms. Children with two parents who have a history of dyslexia are even more likely to be severely impaired compared to those who have one or no affected parents.

In addition, neuroimaging studies show that pre-literate children with family histories of dyslexia have weaker performance in speech, oral language, rapid-automatic-naming tasks, letter knowledge and phonological awareness skills. Parental literacy also predicts and explains a child’s eventual reading and spelling ability.

Although some researchers explicitly discourage the practice of using family history as a screening tool for dyslexia, Lanick et al. argue that family history in conjunction with other information is useful for identifying pre-literate children who are potentially at risk of experiencing reading difficulties, allowing for effective interventions to be put in place early. Even if these children are subsequently found not to have dyslexia, having the intervention would not be detrimental.

However, an underlying difficulty in using family history is determining whether or not parents and other family members have dyslexia. They may not have had access to or the financial means to obtain a formal assessment or equally they may not have received high quality instruction or necessary support structures. For these people, Lanick et al. suggest using the 23(+3)-item Adult Reading History Questionnaire. However, it only correctly identifies individuals as having dyslexia 75.9% of the time and of more concern it only has a success rate of 48.1% for identifying non-dyslexic individuals. In other words, it is over-identifying people as having a reading difficulty when in fact they are actually good readers.

In conclusion, although there is a good case for using family histories as a screening tool for pre-literate children, self-reported questionnaires completed by parents without a formal diagnosis need to be treated with some level of caution.


Lasnick, O., Feng, J., Quirion, A., Hart, S., & Hoeft, F. (2022). The importance of family history in dyslexia. The Reading League Journal, 3 (2), 35-40