ESPE Abstracts

Background: The majority of children with primary nephrogenic diabetes insipidus grow below the third centile.

Objective and hypotheses: Effect of rhGH treatment on growth in a patient with primary nephrogenic diabetes insipidus.

Results: The patient is an 11-years and 2 month old Caucasian boy of unrelated healthy parents. At the age of 7 years and 9 month he was admitted to our hospital for evaluation of polydipsia and polyuria. His body height was 116.0 cm (−1.78 S.D.s). Urine volume was 4165 ml/day (5.2 l/m²). During a water deprivation test, urine osmolality was below 200 mosm/l while plasma sodium and plasma osmolality increased to 140 mmol/l and 305 msom/l respectively. Administration of desmopressin revealed no increase in urine osmolality and a mutation in the Aquaporin two gene was found during molecular analysis (c.732del C in exon 4 of the AQP2 gene). Treatment with hydrochlorothiazide (2 mg/kg per day) and amiloride (0.2 mg/kg per day) led to a decrease of urine output to 2800 ml/day (3.5 l/m²). At the age of 9 years and 6 months his height was 125.3 cm (−1.59 S.D.s). Levels of IGF1 and IGFBP3 were 90 μg/l (−2.05 S.D.s) and 2.0 mg/l (−1.41 S.D.s), two GH stimulation tests revealed low GH levels below 8 ng/ml and GH treatment was started with 0.8 mg/day s.c. (0.029 mg/kg). He showed a good catch-up growth. At the age of 11 years and 2 months his height was 140.3 cm (−0.55 S.D.s). Levels of IGF1 and IGFBP3 were within the normal range (181 μg/l (−0.34 S.D.s) and 2.71 mg/l (−0.52 S.D.s) respectively).

Conclusion: Our patient had a GH deficient state and rhGH treatment induced impressive catch-up growth. GH deficiency should be investigated in short children with nephrogenic diabetes insipidus.