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The role of Trisomy 21 in causing specific speech and language development is discussed by Paoloni-Giacobino and colleagues in a recent report of the development of a 14 year old girl with mosaic Down syndrome.

Trisomic cells are reported as being from 0.7% – 12% in different cell lines. This young girl is reported to have moderately delayed articulation and phonology and reduced fluency in her speech (affecting speech clarity and intelligibility). She also has significant delays in grammar but no impairment in her pragmatic (use of language) skills or auditory memory skills. She has an IQ score of 95 indicating that she has age-appropriate general mental abilities.

Her only difficulties are in the speech and language domain, leading the authors to suggest a direct dosage effect of a gene or genes on chromosome 21 on speech and language skills – not one that is mediated by general cognitive impairments.

Sue Buckley

Original research paper

Paoloni-Giacobino A, Lemieux N, Lemyre E, Lespinasse J. Specific language impairment as the prominent feature in a patient with a low-level trisomy 21 mosaicism. Journal of Intellectual Disability Research. 2007;51(5):401-405. doi:10.1111/j.1365-2788.2006.00912.x