Acid-labile subunit levels and the association with response to growth hormone treatment in short children born small for gestational age.

AIMS: To determine acid-labile subunit (ALS) levels in short small for gestational age (SGA) children and to assess the relationship between ALS levels and several clinical and laboratory characteristics. Also, to assess whether adding ALS levels to a growth prediction model might improve the long-term growth prediction. DESIGN/
METHODS: ALS levels were measured in 312 short SGA children at the start of growth hormone (GH) treatment.
RESULTS: Median (interquartile range) ALS of all subjects was -0.5 SDS, significantly below the 0 SDS (p < 0.001). In 34 children (11%), ALS levels were ≤-2 SDS. ALS SDS correlated significantly with height SDS (r = 0.24, p < 0.001), weight SDS (r = 0.30, p < 0.001), BMI SDS (r = 0.20, p = 0.001), IGF-I SDS (r = 0.56, p < 0.001) and IGFBP-3 SDS (r = 0.67, p < 0.001). ALS SDS was also positively correlated with fasting insulin (r = 0.41, p < 0.001) and glucose levels (r = 0.33, p < 0.001), and HOMA-IR (r = 0.35, p < 0.001). Baseline ALS levels contributed to the long-term growth prediction of GH treatment (5%, p < 0.001).
CONCLUSION: Short SGA children tend to have lower ALS levels compared to controls, albeit less reduced than IGF-I and IGFBP-3 levels. Our data suggest that ALS may be involved in glucose homeostasis. Determination of ALS levels before the start of GH treatment in short SGA children contributes moderately to a more accurate prediction of the growth response to GH treatment.