• Growth occurs in three separate phases, all of which are under different nutritional and/or hormonal controls:
◦ infantile (mainly nutritional)
◦ childhood (hormonal, mainly growth hormone (GH))
◦ pubertal (hormonal; GH and sex steroids acting synergistically).
• Height:
◦ should be measured supine up until 2 years of age, and standing after that, and plotted on appropriate charts
◦ is a normally distributed variable, with extremes (0.4th/2nd centiles and 99.6th/98th centiles) arbitrarily defined as short and tall stature respectively.
• Two major sets of genes determine height and rate of development; the first is assessed using mid-parental and target height, and the second using bone age.
• Short stature:
◦ Failure to achieve an acceptable height can be due to a primary growth problem, or secondary to an underlying disorder.
◦ Causes include familial, genetic disorders (syndromic), small birth size, chronic illness, psychological, environmental, and endocrine.
◦ Generally, short stature due to a hormonal issue is associated with (relative) overweight, and that due to an underlying chronic disorder with (relative) underweight.
◦ GH therapy is licensed for short stature in children in the following situations: GH deficiency, Turner syndrome, chronic renal insufficiency, children born small for gestational age, Prader–Willi syndrome, and SHOX deficiency.
• Tall stature:
◦ Although in theory this should present as frequently as short stature, in practice this is not the case.
◦ The commonest cause of tall stature is constitutional, although other forms include:
■ syndromic: e.g. Klinefelter, Marfan, and Sotos syndromes
■ hormonal: GH, sex steroid excess.
◦ Therapy (sex steroids, GH blockade, epiphyseal stapling) is less effective than in short stature.
