Turner syndrome is one of the most commonly delayed diagnoses in the UK — many girls are not diagnosed until their teens. Turner syndrome (45,X or mosaic variants) affects approximately 1 in 2,000 girls and presents with: short stature (the commonest presenting feature), primary amenorrhoea, webbed neck, wide carrying angle (cubitus valgus), broad chest with widely spaced nipples, and cardiovascular abnormalities (aortic coarctation and bicuspid aortic valve). The diagnosis is frequently delayed because: (1) girls with Turner's may have relatively normal height in childhood (short stature may only become apparent in adolescence when the pubertal growth spurt fails to occur); (2) the distinctive physical features are subtle and not reliably identified without systematic examination; (3) physicians may wait for amenorrhoea before investigating, by which time the girl is in her mid-teens. Any girl who is consistently below the 2nd centile for height without a clear familial explanation, or who has any two of the characteristic features, should be referred for karyotype or appropriate genomic testing via paediatric endocrinology/genetics — mosaicism may give few classic features. Growth hormone therapy can improve adult height in Turner syndrome, but timing is a specialist decision based on age at diagnosis, height, growth velocity, ovarian function, bone age and psychosocial factors; not all girls with Turner syndrome require somatropin (NICE TA188).

Coeliac disease is the most common systemic cause of unexplained short stature in UK children — many coeliac children present without gastrointestinal symptoms (silent coeliac disease), with short stature, iron-deficiency anaemia, or fatigue as the sole presenting features. Anti-tissue transglutaminase IgA (anti-tTG IgA) combined with total serum IgA (to exclude IgA deficiency, which causes false-negative anti-tTG) is the recommended first-line screening test per NICE NG20. The test should be performed on a normal gluten-containing diet (the antibody disappears within weeks of starting a gluten-free diet, making the test falsely negative if gluten has been restricted). GPs encountering any child with unexplained short stature, growth faltering, or iron-deficiency anaemia should routinely screen for coeliac disease with anti-tTG IgA + total IgA. A positive test needs paediatric gastroenterology confirmation — duodenal biopsy, or a no-biopsy pathway for very high tTG levels (BSPGHAN/ESPGHAN criteria) — — a strongly positive result does not automatically mean biopsy is always required; paediatric gastroenterology applies the current ESPGHAN/NICE pathway. Do not start a gluten-free diet before specialist assessment. After diagnosis, growth may improve on a strict gluten-free diet, depending on age, severity, adherence, nutritional status and other disease.

Bone age X-ray (left hand and wrist radiograph assessed by a paediatric radiologist using the Greulich and Pyle atlas or TW2 method) is one of the most useful investigations in short stature assessment — it compares the child's skeletal maturation to their chronological age. The findings guide interpretation: (1) Bone age significantly delayed vs chronological age (e.g., 10-year-old child with bone age of 7–8 years) = consistent with constitutional delay of growth and puberty (CDGP), but also seen with hypothyroidism, growth hormone deficiency, chronic disease, malnutrition, glucocorticoid exposure and some genetic syndromes — in CDGP the child may still have significant growth potential and puberty will come late; (2) Bone age approximately equal to chronological age with short stature = the child's skeleton is aging at the expected rate but at a lower height — likely familial short stature, less growth potential remaining, or endocrine cause; (3) Advanced bone age (older than chronological age) in a short child = concerning for early puberty with premature epiphyseal fusion, or chronic glucocorticoid use. Bone age is supportive rather than diagnostic — interpret it with growth velocity, mid-parental height, puberty, examination and systemic features. It should generally be arranged through paediatrics/endocrinology when it will influence management, and is not usually required for every child with familial short stature.

Turner syndrome karyotyping in all girls with unexplained short stature is standard practice — the karyotype (chromosomal analysis from a blood sample) definitively identifies 45,X or mosaic Turner syndrome. Karyotype or appropriate genomic testing should be arranged through paediatric endocrinology/genetics, or a clearly agreed local arrangement; Turner syndrome can occur with mosaicism and few classic physical features. The clinical implication of the delayed Turner diagnosis is significant: growth hormone therapy (licensed for Turner syndrome in girls — NICE TA188) is specialist-initiated and monitored, and its timing depends on age at diagnosis, height and growth velocity, ovarian function, bone age and psychosocial factors; not all girls with Turner syndrome require somatropin. Confirmed or suspected Turner syndrome requires specialist paediatric endocrine/genetics referral and coordinated cardiac, renal, hearing, thyroid, metabolic and reproductive surveillance.

NICE TA188 recommends somatropin for growth failure in children with GH deficiency; the diagnostic work-up (auxology, growth pattern, bone age, biochemistry and, where appropriate, stimulation testing with assay-specific cut-offs) is set by paediatric endocrinology rather than by TA188 itself; somatropin should be initiated and monitored by a paediatrician with specialist expertise in growth disorders. TA188 also covers (without GH deficiency): Turner syndrome, Prader-Willi syndrome, SHOX gene deficiency, chronic renal insufficiency, and persistent growth failure after being born small for gestational age. GH is not automatically indicated for height below a specific centile alone, familial short stature, constitutional delay, or Noonan syndrome unless the relevant licence/specialist criteria are met. GP role in GH therapy: prescribing under an agreed shared-care protocol (use the current local protocol, e.g. Local, rather than this general guide) — dose changes remain specialist-led and monitoring arrangements must be explicit; injection site rotation advice (lipoatrophy prevention); and recognising side effects needing urgent specialist contact and same-day assessment (benign intracranial hypertension — papilloedema, headache — and hip pain suggesting slipped capital femoral epiphysis — SCFE, which is more common with GH therapy).

The psychological impact of constitutional delay of growth and puberty (CDGP) in adolescent boys is frequently underestimated — a 14-year-old boy who is significantly shorter than all his peers and has not yet begun puberty experiences profound social difficulties: exclusion from sport teams, bullying, difficulties with romantic relationships, and severe self-esteem damage. Parents (particularly fathers who experienced CDGP themselves) are often dismissive: 'I was the same at his age and I turned out fine.' While CDGP has an excellent ultimate prognosis (normal adult height and fertility), the psychological harm during the years of delayed development is real. In current paediatric endocrine practice, treatment to advance puberty (a short course of testosterone in boys, prescribed by paediatric endocrinology) is appropriate when severe psychological distress is present, particularly when bone age is sufficiently delayed that a short course will not compromise final adult height. This treatment decision should be made in consultation with paediatric endocrinology, but GPs should raise the option with families rather than waiting passively.

The IGF-1 monitoring principle for GH therapy reflects the pharmacological mechanism — GH does not act directly on the growth plate but stimulates hepatic production of IGF-1 (insulin-like growth factor 1), which then acts on chondrocytes to promote longitudinal bone growth. IGF-1 levels therefore reflect GH action at the tissue level and are the preferred biomarker for GH therapy monitoring. The target: age- and sex-matched IGF-1 in the mid-normal range (approximately 0 to +2 SDS). Supranormal IGF-1 (>+2 SDS) suggests over-treatment and should trigger dose reduction (long-term supranormal IGF-1 is associated with increased cancer risk — this is the principal long-term safety concern with GH therapy). Sub-normal IGF-1 suggests under-dosing or poor compliance. IGF-1, growth and adverse-effect monitoring (including glucose intolerance) follow the specialist protocol; any GP responsibilities must be stated explicitly in the shared-care agreement.

The Child Growth Foundation (CGF) is a UK charity that provides excellent patient information on all aspects of growth disorders — their website (childgrowthfoundation.org) has condition-specific information sheets for parents and young people covering Turner syndrome, GH deficiency, CDGP, and skeletal dysplasias, written in accessible language. GPs should routinely signpost families dealing with growth concerns to the CGF as a trusted resource. The Turner Syndrome Support Society (tsss.org.uk) is a condition-specific charity providing peer support, information on current management standards, and advocacy for appropriate investigation and treatment timelines. GPs who identify Turner syndrome should provide the family with these resources at the same consultation as the diagnosis discussion.

Slipped capital femoral epiphysis (SCFE) is a specific complication of GH therapy that GPs in shared care must know — GH therapy increases growth rate, which temporarily increases the shear stress on the growth plate of the femoral head. In susceptible children (particularly obese, or those with GH deficiency who are growing rapidly with treatment), the femoral head can slip off the femoral neck at the growth plate. Clinical presentation: limp + hip pain (sometimes referred to the knee) in a child on GH therapy. The risk period is during the first 6–12 months of GH therapy when growth rate is fastest. Action: same-day orthopaedic assessment (urgent surgical pinning prevents further displacement and avascular necrosis) and urgent contact with the endocrine team, who direct any change to GH treatment. GPs managing children on GH therapy should document this safety net explicitly at each review and ensure the family knows to report any new hip or knee pain immediately.