Hyperintensity of posterior pituitary on MR T1WI in a boy with central diabetes insipidus caused by missense mutation of neurophysin II gene

We present a 10-year old boy with central diabetes insipidus (CDI) showing hyperintensity in a normal-sized posterior pituitary on magnetic resonance (MR) TI-weighted image (T1WI). He complained of nocturnal enuresis and poly uria. Daily urine volume increased to 4 to 5 L, and AVP plasma level was ve ry low. Polymerase chain reaction (PCR)-amplified exons of the arginine vas opressin (AVP)-neurophysin (NP) II gene were sequenced. Nucleotide-1884 gua nine in Exon 2 was substituted with thymine, which induced a substitution o f glycine for valine at amino acid position 65 in the NP II moiety. However , MR imaging showed hyperintensity in the posterior pituitary on T1WI. Thes e results suggest that the MR findings of the posterior pituitary in CDI ma y vary.