Language, Literacy and Genetic Syndromes

Achievements in genetics have occurred at a dramatic pace during the past several decades. Indeed, the advent of new technologies in molecular genetics and the availability of animal models of human diseases and disorders have brought us to the brink of treatments or even cures for many conditions we thought intractable only a few years ago. At the same time, these technological advances have sometimes outpaced our ability to fully understand their ethical and practical implications. For example, under what conditions is it beneficial to know that one is, or one's future offspring are, at an elevated risk for a life-threatening disease, especially when that risk is real but less than 100%? In short, how can we use genetic information to alter the human condition in ways that maximize benefit, minimize harm, and respect the full range of human traits, characteristics, and abilities?

Genetic technologies have been applied not only to the investigation of human disease but also to a variety of conditions that affect behavior and learning. For example, more than 750 genetic syndromes that result in intellectual disabilities have been identified (Dykens, Hodapp, & Finucane, 2000). These and other genetic syndromes are caused by alterations in genetic material and include deletions of all or parts of chromosomes, changes in the DNA comprising individual genes, and the loss or addition of genes or even entire chromosomes. These and other genetic alterations result in specific constellations of features that can include both relative strengths and weaknesses in the behavioral domain, as well as changes in physical health. Indeed, it is the predictable constellation of features, or the phenotype, that leads a genetic alteration to be labeled as a syndrome.

In this issue of Topics in Language Disorders, we consider five syndromes-Down, fragile X, Williams, velo-cardio-facial, and Turner syndromes-each of which has been thought to involve problems in learning and using language. These syndromes were chosen for this issue for two reasons. First, individuals with these syndromes are likely to be encountered on the caseloads of speech-language clinicians and thus, there is a need for these professionals to have state-of-the-art knowledge. Second, there is a reasonable evidence base regarding the extent of nature of language-related problems in such individuals, although as the reader will see there remains much to learn about all of these syndromes. In addition to providing a summary of the current evidence on language and literacy, each article is designed to provide information on the genetic bases of the syndrome and on the broader phenotype in which language-related problems must be considered. Each author has also tried to develop the implications of the evidence for clinical practice and to make suggestions about necessary future research.

Despite the diversity of the syndromes reviewed and the variable state of knowledge about language and literacy in the affected populations, there are several commonalities across the articles as regards the implications for clinical practice. I point out three implications here. A fuller consideration of the clinical implications of research on the behavioral phenotypes of genetic syndromes can be found in Abbeduto and McDuffie (in press) and Abbeduto and Boudreau (2004).

First, evidence concerning the profile of language and literacy challenges that is characteristic of a particular syndrome can serve as a guide for practitioners as regards the areas of functioning that deserve special scrutiny in assessment and intervention. For example, problems in expressive syntax are likely to be especially severe in individuals with Down syndrome, whereas those with fragile X syndrome are likely to struggle more with the social than the formal dimension of language. Of course, not all individuals with a particular syndrome will match the norm for the syndrome. Nevertheless, the linguistic phenotypes described in the articles in this issue have a high probability of characterizing a reasonably large proportion of affected individuals. Thus, clinicians who are likely to have limited time and resources can use the linguistic phenotypes described to help plan assessment and treatment, while recognizing that the plan must be flexible and adapted as it unfolds to adequately capture the unique characteristics of the client.

Second, although each of the syndromes considered here is characterized by linguistic challenges, the nature, not just the degree of those challenges, varies across syndromes. Again, the reader will learn that syntax appears to pose fewer challenges for individuals with fragile X syndrome than does pragmatics. At the same time, however, there is asynchrony for this population even within the domain of pragmatics. Consequently, the use of tests and measures that yield only a few summary scores that collapse across multiple dimensions of language may well mask clinically important profiles. Thus, a comprehensive language assessment and treatment plan will need to be highly nuanced, multipronged, and involve multiple assessment and treatment formats.

Third, the language and literacy challenges described in the articles do not occur in isolation; instead, they are part of a broader phenotype that includes challenges (and strengths) in other domains of functioning, such as the cognitive and the social-affective. Consequently, linguistic challenges may result directly from challenges in other domains; for example, language delays in some individuals with Down syndrome may result in part from problems in hearing and auditory memory. In addition, challenges in nonlinguistic domains may influence the results of an assessment or intervention; for example, social anxiety in the case of fragile X syndrome may make it difficult to obtain valid results from standardized language tests, especially if the examiner and testing situation are unfamiliar to the client, or such anxiety may make it difficult to implement an intervention. The implication, then, is that nonlinguistic domains must be assessed and may need to be the targets of intervention when working with clients with one of these syndromes.

I conclude with three cautions. First, identifying the language and literacy profile associated with a particular syndrome is, in and of itself, a description, not an explanation. For example, saying that a child has delays in expressive syntax because he or she has Down syndrome actually masks what is likely to be a very complicated set of causal pathways. We could speculate that such pathways might include a compromised immune system, which leads to an increased susceptibility to infection, and anatomical differences in the ear canal that together produce a high rate of ear infections and thus hearing loss, which might well contribute (along with auditory memory problems and more general limitations in quickly processing sensory input) to problems in learning some elements of syntax.

Second, and relatedly, development in all individuals, whether they have a genetic syndrome or are "typically developing," is always the result of the complex interactions of genes and environments over time. So, it is important to avoid assuming that language and literacy impairments are somehow the inexorable result of genes; instead, the learning environment has likely contributed in some way as well. The implication is that changing the environment can lead to better outcomes in language and literacy for all individuals, including those with a genetic syndrome. Unfortunately, we know very little about the ways in which the environments of individuals with these genetic syndromes impact their learning of language and literacy skills. We do know, however, that many aspects of their environments, whether in the school or in the community, are less supportive of language and literacy than should be the case.

Finally, much of the research on language and literacy in particular syndromes is designed to uncover areas of impairment, and this is reflected in the articles in this issue. This approach is understandable because impairments are directly or indirectly the targets of treatment by professionals. At the same time, however, it is important to recognize that this focus on impairments should not blind us to the many strengths that characterize any individual with one of these syndromes. These areas of strength often can be "leveraged" to help treat and remediate areas of weakness. Even more importantly, we should not let our focus on impairments blind us to the inherent worth of any individual and the great joy and benefit that he or she brings to family, community, and society.

Leonard Abbeduto, PhD

Charles J. Anderson Professor of Education, Waisman Center and Department of, Educational Psychology, University of Wisconsin-Madison

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