Language phenotypes in children with sex chromosome trisomies.
Bishop DVM., Brookman-Byrne A., Gratton N., Gray E., Holt G., Morgan L., Morris S., Paine E., Thornton H., Thompson PA.
Background: Sex chromosome trisomies (47,XXX, 47,XXY and 47,XYY) are known to be a risk factor for language disorder, but typical outcomes are hard to estimate, because many cases are identified only when problems are found. Methods: We recruited children aged 5-16 years with all three types of trisomy, and divided them into a High Bias group, identified in the course of investigations for neurodevelopmental problems, and a Low Bias group, identified via prenatal screening or other medical investigations. Children from a twin sample were used to compare the pattern and severity of language problems: they were subdivided according to parental concerns about language/history of speech-language therapy into a No Concerns group (N = 132) and a Language Concerns group (N = 41). Children were individually assessed on a psychometric battery, and a standardized parent checklist. After excluding children with intellectual disability, autism or hearing problems, psychometric data were available for 31 XXX, 20 XXY and 19 XYY Low Bias cases and 13 XXX, 25 XXY and 32 XYY High Bias cases. Results: Variation within each trisomy group was substantial: within the Low Bias group, overall language scores were depressed relative to normative data, but around one-third had no evidence of problems. There was no effect of trisomy type, and the test profile was similar to the Language Concerns comparison group. The rate of problems was much greater in the High Bias children with trisomies. Conclusions: When advising parents after discovery of a trisomy, it is important to emphasise that, though there is an increased risk of language problems, there is a very wide range of outcomes. Severe language problems are more common in those identified via genetic testing for neurodevelopmental problems but these are not typical of children identified on prenatal screening.