NANISMO. – Deficiency in the development of the bodily proportions of the individual, particularly of height, which remain below the extreme limits of the fluctuating variability proper to that ethnic group.
Some authors speak of n. in individuals below 125 cm. in height, others when this shows a deficiency exceeding 20% of the normal value. In n., the development of the bodily forms and of the sexual and psychological attributes is complete or nearly so; this differentiates n. from infantilism.
The causes of n. are extremely varied: racial, hereditary, due to bone, vascular, or renal disorders, to nutritional deficiencies, particularly of vitamins, dystrophic as a result of chronic infections (tuberculosis, syphilis), and most often due to endocrine glands (v.), such as the pituitary, thyroid, and pancreas. N. permits normal health and life expectancy; likewise, the development of intelligence is good, sometimes excellent, except in the cerebral, mongoloid, and hypothyroid forms (cretinism), in which it is accompanied by deficient neuropsychological development (v. also CIGANTISMO).