Turner syndrome (45,XO) is a chromosomal anomaly in female sex with X chromosome fully or partially missing. Incidence: 1 per 2,000-2,500 female births. Turkey estimates 200-250 new cases annually. Diagnosis is simple (karyotype), but it often comes late — missed opportunities are common.
History + epidemiology
- 1938: Henry H. Turner first clinical description (7 patients: short stature
- sexual development insufficiency)
- 1959: Ford et al. identified the 45,XO karyotype
- 2000+: SHOX gene located on X chromosome — main driver of short stature
Chromosomal causes
45,XO classical (50% of cases)
- All cells missing one X chromosome
- Most severe clinical picture
Mosaic (45,X / 46,XX) (30%)
- Some cells 45, others 46
- Clinical picture may be milder
- Spontaneous menses possible in some cases
Structural X anomalies (20%)
- X isochromosome, ring X, partial deletions
- Karyotype + FISH analysis required
Clinical features
Newborn period
- Lymphedema (hand-foot swelling)
- Webbed neck
- Low posterior hairline
- Wide chest + spaced nipples
- Congenital heart anomalies (aortic coarctation, bicuspid aortic valve — 30%)
- Renal anomalies (horseshoe kidney — 30%)
Childhood
- Short stature (most common diagnostic finding)
- Untreated adult height: 143 cm (Turkish population)
- Percentile drop visible from age 2
- Families often think "she'll start later" — diagnosis delayed to 5-6 yrs
Adolescence
- Gonadal dysgenesis — streak ovaries, no estrogen
- Delayed or absent puberty
- Secondary amenorrhea
- Infertility (95% of cases)
Adulthood
- Low bone mineral density → osteoporosis
- High type 2 diabetes risk
- Autoimmune thyroiditis (30%)
- Hearing loss (middle ear anomalies)
Diagnostic algorithm
Triggers — order karyotype
- Newborn lymphedema
- Marked short stature over age 2 (below p3)
- Delayed puberty + short stature (12+ yrs)
- Recurrent otitis media + hearing loss
- Congenital heart anomaly (girl infants screened)
Karyotype analysis
- Peripheral blood lymphocytes (≥30 cells)
- 45,X finding diagnostic
- If mosaicism suspected: >100 cells + extra tissue (skin, oral mucosa)
Post-diagnosis annual screening
- Thyroid (TSH, anti-TPO) — autoimmune comorbidity
- Glucose, HbA1c — diabetes risk
- Liver enzymes
- Lipid panel
- Bone mineral density (DEXA, age 5+)
- Hearing test
- Echo + ECG (cardiac follow-up)
Treatment: GH + estrogen
Growth hormone (GH) therapy
- Start at 4-6 yrs recommended
- Dose: 0.045-0.050 mg/kg/day (higher than standard pediatric)
- Daily subcutaneous injection
- Goal: add +8-12 cm to adult height (143 → ~153)
- Covered by Turkey's SGK
GH success depends on:
- Early start (4-6 yr ideal)
- Dose titration (IGF-1 monitored)
- Compliance (daily injection)
Estrogen replacement therapy
- Start at 11-12 yrs (puberty timed with peers)
- Transdermal (gel or patch) preferred
- Low-dose start, titrate to adult dose over 2 yrs
- 14-15 yrs: progesterone added for menstrual cycle
GH + estrogen combination is standard for Turner; not alternative.
Surgery
- Y chromosome mosaic (45,X/46,XY) → gonadoblastoma risk → prophylactic gonadectomy
- Congenital heart anomaly → cardiovascular surgery if needed
Fertility
- 95% infertility — ovarian dysgenesis
- IVF + donor eggs allows pregnancy
- 5-10% of mosaic cases conceive spontaneously (high miscarriage risk)
- Autologous fertility preservation not possible pre-puberty
- New hope: artificial follicle generation from 45,X individuals (experimental)
Cognitive + psychosocial
- General IQ normal (average)
- Visuospatial weakness (math, engineering harder)
- Social skills sometimes delayed
- Adolescent self-esteem + depression risk increased
- Pediatric psychology + social support standard
Patient and family support resources
The Turner Syndrome Society of the United States provides support networks and educational resources for families, patients and health professionals. Explore Turner syndrome resources.
FAQ
Can my child have Turner if their height is normal?
Mosaic cases may have normal height. If suspected, karyotype is needed. Normal height but absent menses, or congenital cardiac/renal anomaly → karyotype should be considered.
Can a Turner-syndrome child attend regular school?
Yes — IQ is normal. Just extra support in visuospatial subjects may help. Social support + adolescent psychology standard.
How effective is GH therapy?
Started early, adult height improves by 8-15 cm. Therapy lasts 10-12 yrs. Family + child compliance is critical. Long-acting weekly forms emerging.
When should estrogen therapy start?
11-12 yrs to time puberty with peers. Earlier accelerates epiphyseal closure, reducing height gain. Endocrinology-supervised.
Bottom line
Turner syndrome is largely manageable with early diagnosis + multidisciplinary follow-up. Short stature + secondary amenorrhea + congenital cardiac anomaly in a girl → karyotype is standard. For systematic growth tracking, sign up free; if percentile deviation appears, consult pediatrician + endocrinology.