LAUSR

Purpose of Review Describe growth at different periods of life to understand the effects of genetic impairment in FGFR3- related conditions. We hope this data will be used to compare different populations and the effects of future treatments towards growth improvement. Recent Findings The FGFR3 plays a critical role in early mammalian skeletal development, especially in postembryonic linear bone growth; however, little is known about its role during all of the growth process stages. In the achondroplasia growth curve, infancy, childhood, and puberty periods can be well recognized, coexisting with fast changes in body proportions. Summary FGFR3 gain-of-function mutations are responsible for autosomal dominant chondrodysplasias characterized by a severe disproportionate short stature, as thanatophoric dysplasia, severe achondroplasia with developmental delay and acanthosis nigricans, achondroplasia, and hypochondroplasia. While achondroplasia is homogeneous with low variability, hypochondroplasia findings are less constant due to genotypic heterogeneity. In both conditions, birth size is slightly reduced, followed by a period of fast growth deceleration during infancy and a low magnitude pubertal growth spurt, most evident in sitting height. Some phenomena as shifting centile lines during infancy and parent-child height correlation are well described. A slight variability is shown between achondroplasia and hypochondroplasia populations within different ethnic backgrounds.