Congenital adenohypophysis aplasia

Neonatal Hypopituitarism: Approaches to Diagnosis and Treatment

Hypopituitarism is defined as a decreased release of hypophyseal hormones, which may be caused by disease of the pituitary gland disease or hypothalamus. The clinical findings of neonatal hypopituitarism depend on the causes and on presence and extent of hormonal deficiency. Patients may be asymptomatic or may demonstrate non-specific symptoms, but may still be at risk for development of pituitary hormone deficiency over time. Patient history, physical examination, endocrinological, radiological and genetic evaluations are all important for early diagnosis and treatment. The aim of this paper was to present a review of etiological factors, clinical findings, diagnosis and treatment approaches in neonatal hypopituitarism.

Genetic forms of hypopituitarism and their manifestation in the neonatal period

The anterior pituitary gland is a central regulator of growth, reproduction and homeostasis. The development of the pituitary gland depends on the sequential temporal and spatial expression of transcription factors and signalling molecules. Naturally occurring and transgenic murine models have demonstrated a role for many of these molecules in the aetiology of congenital hypopituitarism. These include the transcription factors HESX1, PROP1, POU1F1, LHX3, LHX4, PITX1, PITX2, OTX2, SOX2 and SOX3. Mutations in any of the genes involved in pituitary development may result in congenital hypopituitarism, which manifests as the deficiency in one or more pituitary hormones. The phenotype can be highly variable and may consist of isolated hypopituitarism, or more complex disorders such as septo-optic dysplasia (SOD) and holoprosencephaly. Neonates with congenital hypopituitarism may present with non-specific symptoms, with or without associated developmental defects such as ocular, midline and genital abnormalities. Alternatively, they may be initially asymptomatic but at risk of developing pituitary hormone deficiencies over time. The overall incidence of mutations in known transcription factors in patients with hypopituitarism is low, indicating that many genes remain to be identified. Their characterization will further elucidate the pathogenesis of this complex condition and will shed light on normal pituitary development.