Endocrine Abstracts

A wide range of disorders must be considered when assessing a child with Short stature (SS). The growth hormone (GH)-IGF-1 axis is essential for normal foetal and childhood growth and defects at many points in the axis will result in growth impairment leading to childhood and adult SS. Severe SS causes physical and psychological disadvantages and the underlying defects may be associated with increased morbidity. Comprehensive investigation of patients with abnormal auxology should lead to a diagnosis, particularly in extreme cases. However, the precise aetiology in many children may remain uncertain. One approach to the assessment of SS is to consider the continuum of GH-IGF-1 axis defects from GH deficiency through to GH insensitivity. The common feature of patients within this continuum is IGF-I deficiency. The investigation of a child with short stature should follow established protocols. Detailed clinical assessment should include a thorough medical history and physical examination. Auxological evaluation is crucial and will establish the severity of the defect and the need for further investigations. The presence of subnormal height velocity confirms the need for detailed assessment. During the initial evaluation, non-endocrine pathologies should be excluded e.g. dysmorphic syndromes, skeletal dysplasias, small for gestational age and systemic diseases. Disorders of GH action frequently present with short stature in childhood. The growth failure is often clinically significant and may be extreme. Determination of GH secretion is recommended in patients with clinical and auxological features of GH deficiency (GHD) and/or IGF-1 levels below or in the low normal range for age and gender. A peak GH level of <10 μg/l may be considered supportive of this diagnosis although many centres now use the stricter criteria of <7.0 μg/l. In patients with normal GH secretion, defects in GH action i.e. GH insensitivity (GHI) should be considered. GHI is characterised by abnormal auxology, normal or elevated GH secretion and IGF-1 deficiency although a wide range of phenotypes and biochemical characteristics are seen. These disorders may result from defects in the GH receptor (GHR) (Laron syndrome) or post-GH receptor (downstream) defects. In its severe form, GHI is associated with dysmorphic and metabolic abnormalities.