This paper describes a case study of a Chinese brain-injured patient with mild dyslexia and more severe dysgraphia. The distributions of his reading and writing errors across tasks are consistent with previous reports. Semantic errors predominated in naming tasks in both modalities, while the preponderance of LARC or phonologically similar errors in reading and phonologically plausible errors in writing-to-dictation was found. Furthermore, his writing errors showed that the semantic radical could be replaced, omitted, or added, whereas only substitutions or deletions of the phonetic radical were observed. The finding that had not been reported before was the existence of a semantic relationship between the substituting or inserted semantic radicals and their target word in many non-character responses. This was taken as evidence for models of the mental lexicon where orthographic units of different sizes are arranged at the same level and semantic radicals are directly connected with semantic features.