Objective Constitutional delay of growth and puberty (CDGP) is a frequent variant of the normal leading to short stature and/or pubertal delay. To distinguish CDGP from hypogonadotropic hypogonadism (HH), we evaluated height, growth and weight pattern of CDGP and HH in the first 5 years of life. Design and patients We studied retrospectively height and weight in the first 5 years (y) of life in 54 boys with CDGP and 8 boys with HH. Results In boys with CDGP, height‐SDS decreased (change −0.94 (interquartile range [IQR] −1.69 to −0.05); P < 0.001) between birth and 2 years. BMI‐SDS decreased (change −0.38 (IQR −1.21‐0.16); P < 0.001) in the same time period. There were no significant changes in height‐SDS or BMI‐SDS between 2 years and 5 years, while height‐SDS (change + 1.49 (IQR 1.02‐1.95); P < 0.001) and BMI‐SDS (change + 0.91 (IQR 0.12‐1.69); P < 0.001) increased between pubertal and adult age. In boys with HH, height‐SDS and BMI‐SDS did not change significantly in the first 5 years of life. Height‐SDS decreased (change −1.39 (IQR −1.96 to −0.67); P = 0.018) significantly between 5 years of life and puberty, while there were no significant changes in BMI‐SDS in this time period. At pubertal age, BMI‐SDS was significantly (P = 0.001) higher in boys with HH compared with boys with CDGP. Conclusion Height deflection and weight deflection in CDGP occur already during the first two years of life in contrast to HH. This different pattern of growth and weight might be helpful to distinguish CDGP from HH.

Background: For children with retarded bone ages such as in constitutional delay of growth and puberty (CDGP) there are no specific methods to predict adult height based on bone age. Widely used methods such as Bayley-Pinneau (BP) tend to overestimate adult height in CDGP. Objective: We aimed to develop a specific adult height prediction model for teenage boys with retarded bone ages >1 year. Methods: Based on the adult heights of 68 males (median age 22.5 years) a new height prediction model was calculated based on 105 height measurements and bone age determinations at a median age of 14.0 years. The new model was adapted for the degree of bone age retardation and validated in an independent cohort of 32 boys with CDGP. Results: The BP method overestimated adult height (median +1.2 cm; p = 0.282), especially in boys with a bone age retardation ≥2 years (median +1.6 cm; p = 0.027). In the validation study, there was no significant difference between adult height and predicted adult height based on the new model (p = 0.196), while the BP model led to a significant overestimation of predicted adult height (median +4.1 cm; p = 0.009). Conclusions: The new model to predict adult height in boys with CDGP provides novel indices for height predictions in bone ages >13 years and is adapted to different degrees of bone age retardation. The new prediction model has a good predictive capability and overcomes some of the shortcomings of the BP model.

ObjectiveConstitutional delay of growth and puberty (CDGP) is a tempo variant with a good prognosis. Healthy late‐maturing adolescents grow slower than postulated by age‐related references, and therefore, CDGP is frequently confused with growth hormone deficiency (GHD). For differential diagnosis, height velocity references for CDGP are needed.Design and PatientsHere, we provide height velocity data for late‐maturing boys based on mixed longitudinal and cross‐sectional observations in a group of 38 German adolescents with proven CDGP and compare them with cross‐sectional observations in a group of 164 adolescents with organic GHD from the National Cooperative Growth Study registry.ResultsIn the critical age interval from 13.4 to 14.9 years, the growth of prepubertal adolescents with CDGP was faster (mean/median height velocity, 5.2/5.4 cm/years; quartiles, 4.4‐6.2 cm/years) than that of prepubertal adolescents with organic GHD (3.5/3.2 cm/years; quartiles, 2.0‐4.4 cm/years) in the cross‐sectional analysis (p < .0001). Based on our mixed longitudinal and cross‐sectional analysis, the height velocity of adolescent boys with CDGP exceeded previous model calculations on average by 1.0 cm.ConclusionsIn conclusion, prepubertal adolescents with CDGP grow faster than patients with organic GHD. Previous model estimates underestimated height velocity of boys with CDGP.