The central diabetes insipidus associated with septo-optic dysplasia (de Morsier syndrome)

Introduction
Septo-optic dysplasia (SOD) is a rare congenital heterogeneous malformation with postulated genetic and environmental etiology. Septo-optic dysplasia is characterized by classic triad: optic nerve hypoplasia, midline brain malformation and hypothalamic-pituitary endocrine deficiencies. The most common hormonal deficiencies affect growth hormone and gonadotropin but it can also be lower levels of the other hormones. The rarest form of hormone deficiency is the deficiency of the antidiuretic hormone.

Case report
The boy was born in 39th week of pregnancy in general good condition. Weakened suction reflex and spitting resulted in substantial difficulties with breastfeeding. After transfontanelle ultrasonography central nervous system defect was suspected. In the 5th month of life MRI confirmed septo-optic dysplasia on the basis of anterior genu of corpus callosum and septum pellucidum agenesis, both optic nerves and optic chiasm hypoplasia, pachygyria and polimicrogyria of the right frontoparietal cortex. Neurological examination revealed axial laxity, psychomotor development delay, difficulties in keeping eyes fixed as well as rotary and horizontal nystagmus. At the age of 3 years he underwent the endocrinological consultation due to polydipsia and polyuria. The tests revealed lower urine specific gravity tests results, therefore diabetes insipidus was diagnosed. The boy still receives desmopressin and there are no signs of central diabetes insipidus. Currently, the boy is under a multi-disciplinary medical care.

Conclusions
The attention should be focussed on early diagnosis, mutli-specialized care and treatment SOD. Hypopituitarism ranges from isolated to multiple hormone deficits, with diabetes insipidus in a minority. Although rare, SOD is an important cause of congenital hypopituitarism and should be considered in all children with midline defects and optic nerve hyploplasia.