A minor one, it left him with a rare and paradoxical infirmity, alexia sine agraphia, the inability to read but not the inability to write.
From the boston.com
Alexia can also co-occur with agraphia, the specific loss of the ability to produce written language even when other manual motor abilities are intact.
From the en.wikipedia.org
More examples
A loss of the ability to write or to express thoughts in writing because of a brain lesion
Dysgraphia (or agraphia) is a deficiency in the ability to write, regardless of the ability to read, not due to intellectual impairment.
Acquired disturbance of writing due to brain injury (Love and Webb, 1996, p. 314)
Inability to communicate ideas in written language not due to mechanical dysfunction; typically results from damage to the parietal lobe.
(ah graf' e ah) Loss of ability to write (a form of aphasia). Symptom common to tumors of the parietal lobe of the dominant cerebral hemisphere.
Inability to write. This term may also be used to specify specific disorders of spelling.
Writing difficulty accompanying some aphasias and characterized by mistakes and poorly formed letters.
An acquired condition of impaired or absent writing ability