Endocrine Abstracts

JOINT1912

Objective: This project aims to better understand the rates of developmental delay and neurodevelopmental disorders in patients with achondroplasia. Achondroplasia is the most common genetic cause of short stature world-wide and is associated with a range of skeletal abnormalities and resultant chronic sequalae. Due to anthropomorphic differences, the developmental profile in achondroplasia is unique, particularly in the area of gross motor skills, with skills such as independent sitting and walking often being achieved later than other children. Achondroplasia it is not thought to be associated with neurodevelopmental abnormalities. It is noteworthy however that other conditions caused by variants in same gene (FGFR3) are associated with higher rates of neurodevelopmental abnormalities. There is also increasing anecdotal evidence of higher rates of neurodevelopmental disorders in achondroplasia patients. This relationship is however poorly explored and warrants further assessment.

Methods: Retrospective developmental milestones and neurodevelopmental data was collected from all individuals with a diagnosis of achondroplasia seen in the specialist achondroplasia clinic at the Evelina London Children’s Hospital. Data regarding additional procedures and diagnosis was also collected. Developmental data was compared to the gold standard achondroplasia development charts (Ireland et al), using the 90th percentile cut-off for delays. Neurodevelopmental disorder rate, in particular Autism, ADHD and Special Education Needs in this cohort was compared to population prevalence.

Results: In this study, data from 240 children with achondroplasia was included. In total 52 children (21.6%) had a delay in one or more developmental domains with respect to achondroplasia milestones. Looking at specific milestones (Independent walking and first word), the proportion greater than the 90th centile cut-off for delay was not statistically different to that seen in the Australian cohort assessed by Ireland et al. When assessing neurodevelopmental disorders, statistically higher rates of autism (Bonferroni corrected P=0.0032) were seen in this cohort when compared to population prevalence. When assessing the rates of special education needs, the cohort as a whole did not have higher rates of special education needs compared to population prevalence. When specifically assessing those with a developmental delay there was a higher rate of long term special education needs when compared to population prevalence (Bonferroni corrected P=0.031).

Conclusions: This large cohort provides valuable insights into the extent of developmental delay and neurodiversity in achondroplasia patients. It offers further evidence of increased neurodevelopmental disorders, particularly autism, and highlights a potential link between early developmental delays and long-term special education needs in Achondroplasia patients.