Multiethnic WHO growth charts may not be optimal in the screening of disorders affecting height: Turner syndrome as a model.

I n 2006, the World Health Organization (WHO) published multiethnic growth charts for children younger than 5 years compiled of growth data of 6669 infants from 6 different countries (the United States, Norway, Oman, Brazil, India, and Ghana). Originally, the rationale for the construction of the multiethnic WHO standards stemmed from an earlier study that reported nearly similar growth patterns in infants and children from diverse ethnic backgrounds when their physiological needs are met and the environment supports healthy development. Adult height varies significantly among populations and is strongly genetically determined, with heritability estimates around 80%. Therefore, the childhood linear growth patterns are probably not as strongly determined by the optimal nutritional, environmental, and psychosocial factors as the weight patterns. In this respect, the original assumption of uniform growth among populations may be incorrect and adversely affect the screening of growth disorders. At least 125 countries have adopted the WHO growth charts for nationwide use in childhood growth monitoring (Mercedes de Onis, WHO, written communication, November 7, 2011). Nevertheless, the WHO charts have not been sufficiently tested in the context of the screening of abnormal linear growth in the general population in developed countries. We tested the performance of the WHO charts against a population-specific growth reference in the screening of Turner syndrome (TS). This condition is often regarded as a model condition to justify screening of height disorders because short stature or poor growth may be the only presenting sign, and an early diagnosis is important because of treatable comorbidities and timely introduction of height-promoting therapies to improve adult height.