Differences in carbohydrate tolerance in Turner syndrome depending on age and karyotype.

Carbohydrate homeostasis was evaluated in 47 girls with Turner syndrome and in 25 "short normal" girls by means of an oral glucose tolerance test. Of the Turner patients 34% showed an impaired glucose tolerance vs 8% of the controls (chi 2 = 5.9, P less than 0.05). Mean glucose levels were significantly higher and mean insulin levels and insulinogenic index significantly lower in young Turner patients aged 5-12 years but not in adolescents aged 12-16 years. In both groups of patients, insulin levels and the insulinogenic index were significantly lower than those of the controls. In Turner patients between 12 and 16 years, carbohydrate tolerance improved and this may be explained by the lack of oestrogen release in these patients. Glucose tolerance was normal in patients with mosaicism. We conclude that (1) carbohydrate tolerance is defective in young children with Turner syndrome but improves in puberty due to the almost complete absence of oestrogen-progestogen secretion; (2) a difference in carbohydrate tolerance is evident depending on karyotype.