Helen Leonard

Aim To compare growth in individuals with cyclin‐dependent kinase‐like 5 (CDKL5) deficiency disorder with population norms and to investigate the effect of gastrostomy on growth. Method The longitudinal study included 353 individuals from the International CDKL5 Disorder Database with any anthropometric measurement in baseline and/or follow‐up questionnaires. The British 1990 growth reference was used to determine the age‐ and sex‐standardized z‐score. Repeated cross‐sectional data were fitted using a Gaussian linear regression model with generalized estimating equations. Results All growth parameters were below the general population norm (mean z‐scores: weight −0.97, height −0.65, body mass index [BMI] −0.81, head circumference −2.12). The disparity was particularly pronounced for all anthropometric measurements after 4 years of age except for BMI. Moreover, individuals with gastrostomy placement were shown to have a larger decrease than those without. Interpretation In addition to weight, height, and BMI, head circumference was also compromised in this disorder. Microcephaly could be considered a helpful diagnostic feature, especially in adults. Any benefit of gastrostomy on weight and BMI was mainly seen in the early years.