Growth Curves for Children with X-linked Hypophosphatemia.

<bold>Context: </bold>We characterized linear growth in infants and children with X-linked hypophosphatemia (XLH).<bold>Objective: </bold>Provide linear growth curves for children with XLH from birth to early adolescence.<bold>Design: </bold>Data from 4 prior studies of XLH were pooled to construct growth curves. UX023-CL002 was an observational, retrospective chart review. Pretreatment data were collected from 3 interventional trials: two phase 2 trials (UX023-CL201, UX023-CL205) and a phase 3 trial (UX023-CL301).<bold>Setting: </bold>Medical centers with expertise in treating XLH.<bold>Patients: </bold>Children with XLH, 1-14 years of age.<bold>Intervention: </bold>None.<bold>Main Outcome Measure: </bold>Height-for-age linear growth curves, including values for the 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles for children with XLH compared to population norms.<bold>Results: </bold>A total of 228 patients (132 girls, 96 boys) with 2381 height measurements were included. Nearly all subjects (> 99%) reported prior management with supplementation therapy. Compared to the Center for Disease Control and Prevention growth curves, boys at age 3 months, 6 months, 9 months, 1 year, and 2 years had median height percentiles of 46%, 37%, 26%, 18%, and 5%, respectively; for girls the median height percentiles were 52%, 37%, 25%, 18%, and 7%, respectively. Annual growth in children with XLH fell below that of healthy children near 1 year of age and progressively declined during early childhood, with all median height percentiles < 8% between 2 and 12 years old.<bold>Conclusion: </bold>Children with XLH show decreased height gain by 1 year of age and remain below population norms thereafter. These data will help evaluate therapeutic interventions on linear growth for pediatric XLH. [ABSTRACT FROM AUTHOR]