Early-Onset Central Diabetes Insipidus due to Compound Heterozygosity for AVP Mutations.

BACKGROUND

Genetic cases of isolated central diabetes insipidus are rare, are mostly due to dominant AVP mutations and have a delayed onset of symptoms. Only 3 consanguineous pedigrees with a recessive form have been published.

CASE REPORT: A boy with a negative family history presented polyuria and failure to thrive in the first months of life and was diagnosed with central diabetes insipidus. Magnetic resonance imaging showed a normal posterior pituitary signal. A molecular genetic analysis of the AVP gene showed that he had inherited a previously reported mutation from his Lebanese father and a novel A>G transition in the splice acceptor site of intron 1 (IVS1-2A>G) from his French-Canadian mother. Replacement therapy resulted in the immediate disappearance of symptoms and in weight gain.

CONCLUSIONS

The early polyuria in recessive central diabetes insipidus contrasts with the delayed presentation in patients with monoallelic AVP mutations. This diagnosis needs to be considered in infants with very early onset of polyuria-polydipsia and no brain malformation, even if there is no consanguinity and regardless of whether the posterior pituitary is visible or not on imaging. In addition to informing family counseling, making a molecular diagnosis eliminates the need for repeated imaging studies.