TY - JOUR
T1 - Reference Growth Charts for Children With 47,XXY/Klinefelter Syndrome
AU - Davis, Shanlee M.
AU - Marshall, Taylor E.
AU - Swenson, Karli S.
AU - Bothwell, Samantha
AU - Nokoff, Natalie J.
AU - Middleton, Amelia
AU - Furniss, Anna
AU - Alkhdour, Maram
AU - Christakis, Dimitri A.
AU - Elliott, Victoria A.
AU - Heeley, Jennifer
AU - Ikomi, Chijioke
AU - Ross, Judith
AU - Stone, Stephen
AU - Vogiatzi, Maria G.
AU - Tartaglia, Nicole R.
N1 - Publisher Copyright:
Copyright © 2025 by the American Academy of Pediatrics.
PY - 2025/12/1
Y1 - 2025/12/1
N2 - BACKGROUND AND OBJECTIVES: Although tall stature is commonly associated with 47,XXY/Klinefelter syndrome (KS), detailed childhood growth patterns are not well-defined. This study aimed to develop KS-specific growth charts for stature-for-age, weight-for-age, weight-for-length (0-24 months), and body mass index (BMI)-for-age (2-18 years). METHODS: We conducted a population-based secondary analysis using clinical data from 6 US pediatric centers. The cohort included 1279 males aged younger than 20 years with a diagnosis of KS and at least 1 outpatient measurement of height and/or weight. Nonparametric quantile regression was used to model age-related growth trajectories. RESULTS: A median of 6 longitudinal growth data points per individual contributed to the creation of KS-specific curves. Key differences from standard reference growth charts included the following: (1) approximately 20% of boys with KS aged younger than 4 years were below the 5th percentile for height, whereas approximately 25% exceeded the 95th percentile by late childhood; (2) height velocity increased in midchildhood (after age 6 years), but without a distinct pubertal growth spurt; and (3) BMI distribution was broader, with approximately 10% of individuals below the 5th percentile and approximately 25% above the 95th percentile. CONCLUSIONS: Boys with KS demonstrate distinct and variable growth trajectories compared with the general population. These KS-specific growth charts offer a valuable clinical tool for monitoring growth, guiding anticipatory counseling, and identifying atypical development patterns.
AB - BACKGROUND AND OBJECTIVES: Although tall stature is commonly associated with 47,XXY/Klinefelter syndrome (KS), detailed childhood growth patterns are not well-defined. This study aimed to develop KS-specific growth charts for stature-for-age, weight-for-age, weight-for-length (0-24 months), and body mass index (BMI)-for-age (2-18 years). METHODS: We conducted a population-based secondary analysis using clinical data from 6 US pediatric centers. The cohort included 1279 males aged younger than 20 years with a diagnosis of KS and at least 1 outpatient measurement of height and/or weight. Nonparametric quantile regression was used to model age-related growth trajectories. RESULTS: A median of 6 longitudinal growth data points per individual contributed to the creation of KS-specific curves. Key differences from standard reference growth charts included the following: (1) approximately 20% of boys with KS aged younger than 4 years were below the 5th percentile for height, whereas approximately 25% exceeded the 95th percentile by late childhood; (2) height velocity increased in midchildhood (after age 6 years), but without a distinct pubertal growth spurt; and (3) BMI distribution was broader, with approximately 10% of individuals below the 5th percentile and approximately 25% above the 95th percentile. CONCLUSIONS: Boys with KS demonstrate distinct and variable growth trajectories compared with the general population. These KS-specific growth charts offer a valuable clinical tool for monitoring growth, guiding anticipatory counseling, and identifying atypical development patterns.
UR - https://www.scopus.com/pages/publications/105023543732
U2 - 10.1542/peds.2025-072193
DO - 10.1542/peds.2025-072193
M3 - Article
C2 - 41198007
AN - SCOPUS:105023543732
SN - 0031-4005
VL - 156
JO - Pediatrics
JF - Pediatrics
IS - 6
ER -