Background: Growth in children with Down's syndrome (DS) differs markedly from that of normal children. The use of DS specific growth charts is important for diagnosis of associated diseases, such as coeliac disease and hypothyroidism, which may further impair growth. Aims: To present Swedish DS specific growth charts. Methods: The growth charts are based on a combination of longitudinal and cross sectional data from 4832 examinations of 354 individuals with DS (203 males, 151 females), born in 1970-97. Results: Mean birth length was 48 cm in both sexes. Final height, 161.5 cm for males and 147.5 cm for females, was reached at relatively young ages, 16 and 15 years, respectively. Mean birth weight was 3.0 kg for boys and 2.9 kg for girls. A body mass index (BMI) >25 kg/m 2 at 18 years of age was observed in 31% of the males and 36% of the females. Head growth was impaired, resulting in a SDS for head circumference of −0.5 (Swedish standard) at birth decreasing to −2.0 at 4 years of age. Conclusion: Despite growth retardation the difference in height between the sexes is the same as that found in healthy individuals. Even though puberty appears somewhat early, the charts show that DS individuals have a decreased pubertal growth rate. Our growth charts show that European boys with DS are taller than corresponding American boys, whereas European girls with DS, although being lighter, have similar height to corresponding American girls.

Although an increase in older mothers was observed in most registers, the prevalence of DS births remained stable in most registers as a result of increasing use of prenatal diagnostic procedures and ToP with DS.

Children with Down syndrome and coexisting neurodevelopmental/neuropsychiatric disorders in addition to intellectual disability and medical disorders constitute a severely disabled group. Based on the results, we suggest that screening is implemented for both ASD and ADHD, at the age of 3 to 5 years and early school years respectively, to make adequate interventions possible.

The combined finding of a greater head circumference SDS and better psychomotor performance indicates that DS subjects may benefit from early GH treatment.