Circulating insulin-like growth factor 1 levels are reduced in very young children with Prader-Willi syndrome independent of anthropometric parameters and nutritional status

Objective Insulin growth factor-1 (IGF-1) is used to evaluate growth hormone (GH) sufficiency and is decreased in children with Prader-Willi syndrome (PWS). Although IGF-1 is negatively affected by body size and nutritional status, both of which are impaired in PWS children, these variables are typically not considered when assessing IGF-1 levels in these subjects. Here, we compared IGF-1 levels in PWS children to controls matched for age, sex, anthropometric parameters, and nutritional status. Design/Patients/Measurements The retrospective analysis included genetically diagnosed PWS subjects (n = 65, median age; 14.0 months) and controls (n = 111, 14.3 months) matched for age, sex, anthropometric parameters (height-standard deviation score [SDS], weight-SDS, body mass index-SDS), and serum albumin levels, a marker for nutritional status. IGF-1 SDS was compared between PWS subjects and controls after adjustment for confounding variables. The GH provocation test was performed in 29 PWS subjects, and IGF-1 SDS was compared between GH-sufficient (n = 20) and GH-deficient (n = 9) subjects. Spearman's rank correlation coefficient was performed to investigate the association between age and IGF-1 SDS. None had received GH or levothyroxine treatment. Results After adjustment for confounding variables, IGF-1 SDS was significantly lower in PWS subjects than controls (-1.56 vs. -1.01, p = .003), while it was not different between GH-sufficient and GH-deficient PWS subjects. Correlation analysis failed to show an association between age and IGF-1 SDS both in control and PWS groups. Conclusions IGF-1 SDS is lower in very young children with PWS independent of anthropometric parameters and nutritional status, suggesting the presence of hypothalamic dysfunction of GH secretion.

Automated summary

This study found that IGF-1 levels were significantly lower in PWS children compared to controls, with no significant difference between GH-sufficient and GH-deficient PWS children. There was no association between age and IGF-1 levels in both control and PWS groups. These findings suggest the presence of hypothalamic dysfunction in GH secretion in young children with PWS.