Growth references for Japanese individuals with Noonan syndrome

Background:Noonan syndrome (NS) is a clinically and genetically heterogeneous syndrome characterized by distinctive facial features, short stature, congenital heart diseases, and other comorbidities. NS-specific growth charts are essential for NS care, but currently no such charts are available for Asian populations.Methods:We conducted a nationwide survey by collaborating with three academic societies in Japan. We obtained the data of 356 clinically diagnosed NS subjects from 20 hospitals. The Lambda-Mu-Sigma method was used for establishing growth charts.Results:A total of 308 subjects (males: 159 and females: 149) were analyzed after excluding 48 subjects because of missing auxological data (26 subjects), presence of complications affecting growth (5 subjects), and extreme longitudinal growth aberrations which lay more than three standard deviation scores from the mean in this population (17 subjects). Genetic analyses were performed in 150 patients (48.7%); 103 (68.7%) were reported to have some abnormalities in the known causative genes. Cardiovascular diseases were found in 256 patients (83.1%). The NS-specific height, weight, and BMI charts were constructed with 3,249 mixed longitudinal and cross-sectional measurements.Conclusion:Growth standards for Japanese individuals with NS were established. These charts are expected to be used in various clinical settings.