Congenital hypopituitarism: clinical, molecular and neuroradiological correlates

Recent studies have suggested that mutations in genes encoding several hypothalamo-pituitary (H-P) transcription factors result in hypopituitarism [isolated GH deficiency (IGHD) and combined pituitary hormone deficiency (CPHD)], which may in turn be related to the neuroanatomy revealed by magnetic resonance (MR) imaging. Although studies have focused on patients with either optic nerve hypoplasia (ONH) or isolated hypopituitarism with normal optic nerves, few studies have compared the two groups. We aimed to relate the clinical phenotype of a large cohort (n = 170) of children with congenital hypopituitarism including septo-optic dysplasia (SOD) attending a single centre to the neuroradiological and genetic findings.

Clinical, biochemical, MR imaging and molecular data were analysed retrospectively in 170 patients with or 'at-risk' (with ONH) of hypopituitarism to determine predictors of hypopituitarism.

The presence of ONH was significantly associated with an absent septum pellucidum [odds ratio (OR) 31.5, 95% confidence intervals (CI) 7.3-136.6, P < 0.001], an abnormal corpus callosum (OR 10.5, 95% CI 3.8-28.6, P < 0.001) and stalk abnormalities (OR 2.3, 95% CI 1.2-4.2, P = 0.009). The risk of hypopituitarism was 27.2 times greater in patients with an undescended posterior pituitary (95% CI 3.6-205.1, P < 0.001). Anterior pituitary hypoplasia (OR 3.1, 95% CI 1.3-7.0, P = 0.006) and an absent pituitary stalk (P < 0.001) were also significantly associated with hypopituitarism. With respect to the type or severity of hypopituitarism, CPHD was more often associated with an abnormal corpus callosum (OR 6.1, 95% CI 1.4-27.4, P = 0.008) and stalk abnormalities (OR 2.8, 95% CI 1.3-6.1, P = 0.006). Male to female ratio was significantly greater in patients with normal optic nerves (3.3:1) as compared with those with ONH (1.2:1). The prevalence of diabetes insipidus, thyrotrophin and ACTH deficiencies was significantly greater in patients with ONH as compared with 'idiopathic' hypopituitarism. Mutations in pituitary transcription factors and genes regulating GH secretion were rare (5/170) in this cohort of patients with sporadic hypopituitarism.

Our data suggest that individuals presenting with ONH are at high risk for neuroradiologic and endocrine abnormalities. The neuroradiologic features are predictive not only of the presence, but also of the type, of hypopituitarism. The association of midline abnormalities with hypopituitarism in this cohort suggests a common developmental origin for these features, the aetiology of which remains unidentified in the majority of cases.