Big Variability in "Little" People

The variegated community of dwarfs is proving to be more heterogeneous than generally thought. Monotropic sexual ateliotic dwarfism is a case in point. Distinguished from other pituitary dwarfs by their normal sexual maturation, individuals belonging in this category have a demonstrable isolated deficiency of immunoreactive growth hormone.¹ Hitherto viewed as a homogeneous assemblage, they are now shown by Merimee and associates² to comprise several distinct groups sharply differentiated by hormonal and metabolic tests and sometimes by patterns of hereditary transmission. These investigators studied 26 American dwarfs and 31 African pygmies in whom they assayed growth hormone and insulin both before and after appropriate stimulation of secretion. They also assessed sensitivities to exogenous insulin as well as responses to growth hormone therapy; and, when possible, they determined modes of inheritance.

From these studies have emerged distinct patterns of values and responses to justify the subdivision of monotropic ateliotic sexual