Growth curves for French people with Down syndrome from birth to 20 years of age.

We present new and complete growth charts for 2,598 healthy French children and adolescents with Down syndrome (DS) from 0 to 20 years old, obtained with highly reliable statistical methods. This study is retrospective and addresses data collected over a period of 12 years, monocentric and with a satisfactory representation of the population nationwide. Final occipito-frontal circumference (OFC) is at the fifth percentile compared to WHO charts, with a drop between 12 and 18 months. Final height is at the first percentile compared to WHO charts for girls and boys with two periods of reduced growth velocity: before 36 months and around puberty. We observed no pubertal growth peak for girls. For boys, pubertal growth peak showed to happen earlier and to be less significant than in the general population. When compared to a previous French study with people affected with DS, pubertal growth acceleration begins at a later age for girls and boys; girls in our study are taller at age 15 (+5 cm), but there is no difference for boys at this age. Overweight is more frequent compared to the typical French population. Mean body mass index (BMI) rises rapidly above the 75th percentile of typical French children as early as age 4, with an earlier age for precocious adiposity rebound. The second period for rapid increase of BMI is around 14 years old. When compared to a previous French study with DS, we did not observe any BMI increase, at least up to the age of 14.