Neurologic manifestations can accompany systemic diseases, and primary disease can be identified with a careful history, physical examination, and laboratory investigations. A 14-year-old girl with paraplegia and absence of deep tendon reflexes in the lower extremities after 2 days of vomiting and diarrhea was referred to our pediatric neurology department with a diagnosis of Guillain-Barré syndrome. Short stature, dehydration, motor and mental retardation, bilateral cataracts, glaucoma, and band keratopathy were detected on physical examination. Hypopotassemia and severe metabolic acidosis were found on biochemical examination. Her paraplegia improved after appropriate fluid and electrolyte replacement, but metabolic acidosis persisted after cessation of intravenous therapy, and isolated proximal renal tubular acidosis was detected. Because she had isolated proximal renal tubular acidosis and other abnormalities, she was diagnosed with Donckerwolcke-Winsnes syndrome.