Short & Tall Stature

Expected adult height: boys ≈ mean of parents’ heights +6.5 cm; girls ≈ mean of parents’ heights −6.5 cm. (Mid-parental height formula: boys = (mum + dad + 13 cm) / 2; girls = (mum + dad − 13 cm) / 2 — then plot on the percentile chart.) The expected adult height typically falls within about 8 cm above or below the mid-parental height.

Use the WHO growth chart <2 years and the CDC chart ≥2 years. In the first 2 years, crossing percentiles can simply reflect catch-up or catch-down growth. Slow velocity = crossing ≥2 percentile lines.

Short stature

Height below the 3rd centile — must distinguish normal physiological variants from pathological causes. This corresponds to more than 2 standard deviations below the mean for age, sex and population.

Cause	Key features
Familial short stature	Growth tracks along centiles; normal bone age
Constitutional delay (common)	Growth falling down centiles; delayed bone age; family history of delayed puberty
Hypothyroidism	Height affected more than weight (weight preserved/increasing); cold intolerance, constipation, dry skin, bradycardia
Growth hormone deficiency	Delayed bone age; height reduced more than weight on the chart (GH is the predominant driver of growth after age 2)
Pathological, may have no other signs	Coeliac disease, Crohn’s disease, chronic kidney disease

Constitutional delay of growth and puberty (CDGP) and familial short stature are commonly confused with each other — both present with normal birth parameters and a “catch-down growth” pattern that stabilises with normal growth velocity after the first 2–3 years of life, but CDGP tends to reach a greater final height than familial short stature, comes with delayed puberty, and its bone age lags chronological age by up to 2 years; familial short stature by contrast has normal bone age and timely puberty. Coeliac disease, cystic fibrosis, juvenile idiopathic arthritis, Crohn’s disease, anaemia, chronic renal insufficiency and chronic malnutrition should all be considered as systemic causes, and genetic syndromes (Turner, Noonan, Prader-Willi, Silver-Russell) or skeletal dysplasias (achondroplasia) should be kept in mind, particularly when dysmorphic features or other systemic signs are present.

Idiopathic short stature may be treated with recombinant human growth hormone, but it is expensive and long-term safety data remain limited — used selectively. hGH is given as a daily subcutaneous injection, with the dose titrated to growth velocity rather than a single fixed dose. Serum IGF-1 is also monitored throughout treatment, both for response and for safety. A long-acting once-weekly hGH formulation (somatrogon) is now approved in Australia for growth hormone deficiency, at the cost of more frequent injection-site reactions than daily injections. Treatment with any hGH preparation is usually stopped once growth velocity falls below about 2 cm/year, or once a bone age of roughly 14 (girls) or 16 (boys) is reached. On the safety question specifically, a large consensus review found no association between growth hormone replacement and primary tumour development or cancer recurrence — though families should still be counselled about recognised local adverse effects, including injection-site reactions and, less commonly, slipped capital femoral epiphysis or raised intracranial pressure.

Who needs further evaluation

Height <2.3rd centile for age (>2 SD below the mean), or a slow growth velocity (crossing ≥2 centile lines).

Workup

1. Bone age assessment (X-ray) — corrects height/growth velocity for skeletal rather than chronological age; online tools (e.g. BoneXpert) can estimate final adult height from this.
2. Mid-parental height — calculate and plot on the percentile chart (see formula above).
3. Puberty assessment — Tanner staging; mother’s age of menarche and other pubertal changes; father’s age of growth spurt/voice change/hair growth.
4. Examination.
5. Investigations: bone-age X-ray; bloods — FBC, LFT, UEC, calcium/ phosphate, coeliac serology, CRP/ESR, TFTs, IGF-1 and IGFBP-3 (if <3 years old). Low IGF-1 raises suspicion of GH deficiency, but is also consistent with inadequate nutrition, hypothyroidism, liver disease, or diabetes.

Tall stature

Height above the 97th centile — a much less common presenting concern, since tall stature is socially well-accepted.

Causes: familial; precocious puberty; GH excess (gigantism); hyperthyroidism; Marfan syndrome, Klinefelter syndrome, homocystinuria.

Management: usually just reassurance. An endocrinologist can accelerate bone maturation with high-dose oestrogen (girls) or testosterone (boys), started shortly after the first pubertal changes appear — rarely used now given modern acceptance of tall stature.