Growth in achondroplasia, from birth to adulthood, analysed by the JPA-2 model

Abstract

ObjectivesIn general population, there are three phases in the human growth curve: infancy, childhood and puberty, with different main factors involved in their regulation and mathematical models to fit them. Achondroplasia children experience a fast decreasing growth during infancy and an “adolescent growth spurt”; however, there are no longitudinal studies that cover the analysis of the whole post-natal growth. Here we analyse the whole growth curve from infancy to adulthood applying the JPA-2 mathematical model.MethodsTwenty-seven patients, 17 girls and 10 boys with achondroplasia, who reached adult size, were included. Height growth data was collected from birth until adulthood. Individual growth curves were estimated by fitting the JPA-2 model to each individual’s height for age data.ResultsHeight growth velocity curves show that after a period of fast decreasing growth velocity since birth, with a mean of 9.7 cm/year at 1 year old, the growth velocity is stable in late preschool years, with a mean of 4.2 cm/year. In boys, age and peak height velocity in puberty were 13.75 years and 5.08 cm/year and reach a mean adult height of 130.52 cm. In girls, the age and peak height velocity in puberty were 11.1 years and 4.32 cm/year and reach a mean adult height of 119.2 cm.ConclusionsThe study of individual growth curves in achondroplasia children by the JPA-2 model shows the three periods, infancy, childhood and puberty, with a similar shape but lesser in magnitude than general population.

Once-weekly TransCon CNP (navepegritide) in children with achondroplasia (ACcomplisH): a phase 2, multicentre, randomised, double-blind, placebo-controlled, dose-escalation trial

“…Natural history studies show that the growth in children aged 2–5 years is relatively high compared to those older than 5 years of age and prior to puberty. 20 , 23 , 24 Results from previous studies have shown higher variability (i.e., standard deviation) in change in AGV at week 52 from a 6-month run-in at baseline compared with AGV at week 52. 13 , 25 This variability might be even more pronounced in a younger trial population when relative AGV is higher.…”

Achondroplasia in Latin America: practical recommendations for the multidisciplinary care of pediatric patients

“…The height is approximately 5.00 SD below the median compared non-achondroplastic populations with a mean adult height of approximately -6 SD [8,10,11,91].Thus, the curves are similar in shape but lesser in magnitude in comparison to the general population in both periods [34,90]. Besides, 72% of that small growth peak is caused by the peak of trunk length [90,92,93].…”

Growth patterns of young achondroplasia patients in Korea and predictability of neurosurgical procedures

“…Growth patterns of height, weight, and HC in achondroplasia patients are quite different from those in the general population [30][31][32][33][34]. Because enchondral bony growth is inhibited in achondroplasia, short stature and macrocephaly are characteristic features of achondroplasia patients [1,2,9].…”