Cognitive development in children with Prader-Willi syndrome receiving early growth hormone therapy

Prader‒Willi syndrome (PWS) is a genetic disorder characterized by hypotonia, feeding difficulties in infancy, excessive eating in childhood, intellectual disability and short stature. Growth hormone therapy (GHT) improves body composition and decreases fat percentage in patients with PWS. However, the effect of GHT on cognitive function is not clear.

The aim of this study was to evaluate the beneficial effects of GHT on cognition in younger patients with PWS.

A retrospective analysis of patients with PWS who received GHT in four hospitals was conducted in Taiwan. Patient demographics, molecular diagnosis, age at GHT initiation, GHT dose, developmental quotient/full-scale intelligence quotient (DQ/FSIQ) scores, and verbal intelligence quotient/verbal comprehension index (VIQ/VCI) scores were analyzed.

This retrospective study included a total of 61 patients. Seven patients who did not receive growth hormone treatment were assigned to the control group, while the remaining 54 patients composed the treatment group. After applying the exclusion criteria, 47 patients were ultimately included in the analysis. Twenty-nine patients were treated before 3 years of age, and eighteen patients were treated after 3 years of age. The DQ/FSIQ score was significantly greater in the younger age group (p < 0.05). Specifically, in the nondeletion type and female groups, younger patients presented significantly higher DQ/FSIQ scores (p < 0.05). Compared with the untreated group, the early GH treatment group had significantly higher VIQ/VCI scores (p < 0.05). According to linear regression, the age at GHT initiation was significantly negatively correlated with the DQ/FSIQ score (β₁ = -1.264, R² = 0.184, F = 4.16, p < 0.05) and the VIQ/VCI score (β_(VIQ)1 = -1.981, R² = 0.242, F = 4.09, p < 0.05).

The initiation of GHT before 3 years of age and as early as possible had a significant effect on cognitive development after adjustments were made for sex and molecular type.