A 21/2-month-old girl presented with feeding difficulties of 8 weeks' duration. She cried, vomited, arched, and became rigid during every feeding. She was suspected of having gastroesophageal reflux disease. Dystonia and developmental delay became apparent at age 8 months. Nasogastric tube feeding and gastrostomy with Nissen's fundoplication were performed at age 7 and 12 months, respectively. She was treated with baclofen, trihexyphenidyl, and antireflux therapy, without benefit. She became severely developmentally delayed with marked head lag, dystonia, and rigidity. Levodopa therapy was initiated at age 21 months. She manifested dramatic improvement over the next year. Dystonia, rigidity, and retching disappeared soon after treatment. She experienced good catch-up in development. She exhibited poor head control and an inability to reach out at age 21 months, but bottom shuffling was observed at age 26 months, and walking and speaking three-word sentences at age 2 years and 10 months. Pertinent issues relating to signs, pathophysiology, genetics, and biochemical defects are discussed briefly.