developmental disability

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A cognitive, emotional, or physical impairment, especially one related to abnormal sensory or motor development, that appears early in life and limits one's ability to learn, communicate, or perform one or more activities of daily life.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun describes life-long disabilities attributable to mental and/or physical, or combination of mental and physical impairments, manifested prior to age twenty-two.