Growth hormone (GH) secretion in children with Noonan syndrome: frequently abnormal without consequences for growth or response to GH treatment

To compare the distribution of body mass index (BMI) in a national representative study in The Netherlands in 1996-7 with that from a study in 1980. Cross sectional data on height, weight, and demographics of 14 500 boys and girls of Dutch origin, aged 0-21 years, were collected from 1996 to 1997. BMI references were derived using the LMS method. The 90th, 50th, and 10th BMI centiles of the 1980 study were used as baseline. Association of demographic variables with BMI-SDS was assessed by ANOVA. BMI age reference charts were constructed. From 3 years of age onwards 14-22% of the children exceeded the 90th centile of 1980, 52-60% the 50th centile, and 92-95% the 10th centile. BMI was related to region, educational level of parents (negatively) and family size (negatively). The -0.9, +1.1, and +2.3 SD lines in 1996-7 corresponded to the adult cut off points of 20, 25, and 30 kg/m(2) recommended by the World Health Organisation/European childhood obesity group. BMI age references have increased in the past 17 years. Therefore, strategies to prevent obesity in childhood should be a priority in child public health.

We describe the largest Noonan syndrome (NS) family reported to date. The manifestations of the affected relatives are discussed. In the absence of a biochemical marker NS is still a clinical diagnosis. The diagnostic criteria that were used are presented compared with other published criteria for diagnosing NS. The large size of this family enabled us to test the possible involvement of candidate regions by multipoint linkage analysis. Both the region surrounding the NF1 locus on chromosome 17 and the proximal part of chromosome 22 could be excluded. Since NS may well be heterogeneous, the use of such a large family in linkage studies of NS should prove indispensable.

We have analysed growth and the major clinical manifestations of 144 patients (89 males, 55 females) with Noonan syndrome from two West German centres. Size at birth was normal in both sexes. In both males and females, the mean height followed along the 3rd per centile until puberty, but decreased transiently due to an approximately 2 year delay in onset of puberty. Final height approaches the lower limits of normal at the end of the 2nd decade of life. The mean adult height was found to be (n = 20) 162.5 cm in males and (n = 13) 152.7 cm in females, respectively. Smoothed means and standard deviations for height were derived. These data may be used for the statistical evaluation of height of Noonan syndrome patients. Except for mental retardation and microcephaly, which are more frequent in males, the relative frequencies of minor anomalies and malformations were found to be similar in both sexes. The characteristic non-cyanotic heart defects in the Noonan syndrome do not appear to have a major influence on growth. The auxological data were compared with those in the Ullrich-Turner syndrome.