Reference Growth Charts for Children With 47,XXY/Klinefelter Syndrome

Area of Science:

• Pediatric Endocrinology
• Genetics
• Growth and Development

Background:

• Tall stature is often linked to Klinefelter syndrome (KS), but detailed childhood growth patterns are not well-established.
• Existing growth charts may not accurately reflect growth trajectories in boys with KS.

Purpose of the Study:

• To develop specific growth charts for stature, weight, and BMI for boys with Klinefelter syndrome (KS).
• To provide a clinical tool for monitoring growth in children diagnosed with KS.

Main Methods:

• A population-based secondary analysis of clinical data from 1279 males under 20 years with KS.
• Nonparametric quantile regression was employed to model age-related growth trajectories using longitudinal data.

Main Results:

• KS-specific growth curves revealed significant deviations from standard charts.
• Height percentiles varied widely, with some boys below the 5th percentile early on and others above the 95th percentile later.
• Height velocity showed a midchildhood increase without a distinct pubertal spurt, and BMI distribution was broader than typical.

Conclusions:

• Boys with KS exhibit distinct and variable growth patterns compared to the general population.
• The developed KS-specific growth charts are valuable for clinical monitoring, counseling, and identifying atypical growth.
• These charts can improve the management of growth in individuals with Klinefelter syndrome.