We present growth curves of 1,726 Turkish children with Down syndrome (DS) between 0 and 18 years of age and investigate the factors that affect growth including congenital heart disease (CHD) and hypothyroidism. Longitudinal measurements of height, weight, and head circumference (HC) were assessed and accompanying major malformations were recorded. Growth curves were monitored using Cole's LMS method. The mean birth length was reduced by À0.5 standard deviation (SD) for Turkish standards in both boys and girls. Pubertal growth spurt of the girls with DS started 1 year earlier, their puberty duration was short and pubertal annual growth rate was inadequate, and as a result the final height was À3.06 SD for Turkish standards. Although the age at onset of pubertal growth spurt and puberty duration of the boys were similar to normal population, their pubertal annual growth rate was inadequate; thus the final height was À2.56 SD for Turkish standards. The final weight values were similar to normal population. The mean HC values of DS children were corresponded to À0.9 SD for Turkish standards at birth; however after 6 months values were below À2 SD. The final HC values were À1.02 SD for boys and À2.21 SD for girls for Turkish standards. We observed that weight was decreased in DS children with severe CHD during first 4 years of life. However, there is no statistically significant difference in values of height and head circumference between patients with or without severe CHD group. In addition, hypothyroidism had no effect on growth in DS patients. Ó 2012 Wiley Periodicals, Inc.Key words: Down syndrome; growth; charts; height; weight; head circumference INTRODUCTION Down syndrome (DS) is the most common chromosomal disorder and leading cause of intellectual disability and growth retardation. Average height is around the À2 standard deviation (SD) for most ages compared to normal population. The growth pattern is impaired from birth to adolescence and particularly during the interval of 6 months to 3 years and puberty [Cronk et al., 1988]. In addition, these patients also have reduced pubertal growth spurt, contributing to the low final height [Cronk et al., 1988;Anner en et al., 1990]. It was demonstrated that children with DS do not have growth hormone (GH) deficiency [Anner en et al., 1986], but hypothalamic dysfunction was reported by Castells et al. [1996]. A study performed by Anner en et al. [1999] revealed that GH was given to children with DS increased growth velocity. However, Myrelid et al. [2010] reported that GH treatment had no effect on final height.Since children with DS have different growth patterns than other normal children, it is critically important to utilize syndrome specific growth charts. First growth charts for DS have been developed by Roche [1965], followed by Rarick and Seefeldt [1974]. Cronk et al. [1988] was studied 780 children with DS between 1 month and 18 years of age and established growth charts with these data in USA and also showed that moderate to severe CHD affected growt...