Constitutional delay in growth and puberty (CDGP) is associated with hypoleptinaemia

OBJECTIVE Serum leptin concentrations are higher in early adolescence compa red with childhood and may play a facilitatory role in pubertal development . Constitutional delay in growth and puberty (CDGP) is a disorder of the te mpo of physical maturation and may be associated with relative hypoleptinae mia. We have therefore compared serum leptin concentrations in normal boys with those in boys exhibiting constitutional delay of growth, controlling f or pubertal status, age and body mass index (BMI), PATIENTS 23 boys with constitutional delay in growth (n=17, prepubertal) an d puberty (n=6, early pubertal) and 88 normal boys (n=64 prepubertal, n = 2 4 Tanner stage 2), MEASUREMENTS Serum leptin was measured in a single, non-fasted morning seru m sample by radioimmunoassay, Using the data from normal boys, leptin stand ard deviation scores (sds) were calculated, to account for the independent influences of age and body mass index (BMI) sds, Both chronological age and bone age were used in the calculation of leptin sds in those with delay. RESULTS BMIsds was significantly lower in prepubertal delays compared with controls but was not different in pubertal subjects. Leptin concentrations were higher in early puberty compared with prepuberty (P<0.001) in normal b oys but were not significantly elevated in pubertal boys with delay compare d with prepubertal delays, Although leptin sds, for both chronological age and bone age, was similar in prepubertal controls and delays, it was signif icantly lower in the pubertal delay group (P<0.05). In controls leptin sds did not correlate with age. However, in delays leptin sds was negatively co rrelated with both chronological age (r=-0.43, P<0.05) and bone age (r= - 0 .68, P<0.01), indicating that in the older delays leptin levels were lower than expected given their age and BMIsds, CONCLUSIONS These data indicate that significantly higher leptin levels in Tanner stage 2 compared with prepuberty are not a prerequisite for progress ion into puberty. However, the absence of elevated leptin concentrations ma y be associated with delayed puberty in boys.