Makindo Medical Notes

Related Subjects: | Osteoporosis | Autosomal Dominant | Autosomal Recessive | X Linked Recessive |Dementias |Chromosomal Defects |Turner's syndrome (Children)

👧 Turner Syndrome (45,XO) is a chromosomal disorder affecting only females, caused by the complete or partial absence of one X chromosome. Because they have only one X, girls with Turner syndrome are more vulnerable to X-linked conditions (e.g., haemophilia, Duchenne muscular dystrophy). Despite this, with appropriate treatment and multidisciplinary care, many individuals live normal and fulfilling lives.

📖 About

• Prevalence: ~1 in 2,500 female live births.
• Most cases are non-mosaic 45,XO, but mosaic forms (45,X/46,XX or 45,X/46,XY) exist and can modify phenotype.
• Short stature and gonadal dysgenesis are cardinal features.
• Unlike Down syndrome, Turner syndrome does not affect overall intelligence, though specific neurocognitive domains may be impaired.

🫀 Cardiovascular Manifestations

• Bicuspid aortic valve (commonest cardiac anomaly).
• Coarctation of the aorta → systemic hypertension in childhood/adulthood.
• Aortic root dilatation & dissection risk: necessitates lifelong surveillance with echocardiography or MRI.
• Other associations: elongated transverse aortic arch, mitral valve prolapse.

👩 Clinical Features

• Growth: Short stature (median adult height ~147 cm). GH therapy can help.
• Craniofacial & Skeletal: Webbed neck, low posterior hairline, shield-shaped chest, widely spaced nipples, cubitus valgus (wide carrying angle), high palate, short 4th metacarpal.
• Lymphatic anomalies: Neonatal hand/foot oedema, congenital lymphedema.
• Ears/Hearing: Recurrent otitis media, conductive & sensorineural hearing loss.
• Neurocognitive: Average intelligence but impaired visuospatial skills, mathematics, and social cognition.
• Other: Hypothyroidism (autoimmune thyroiditis common), pigmented naevi, keloid tendency.

🧬 Endocrine & Reproductive

• Gonadal dysgenesis: Streak ovaries → primary ovarian failure.
• Pubertal delay: Absent or incomplete puberty without HRT.
• Infertility: Nearly universal, though assisted reproduction with donor oocytes is possible.
• Hormonal effects: Low oestrogen → risk of osteopenia/osteoporosis, metabolic syndrome, and early cardiovascular disease.

🧪 Investigations

• Karyotype analysis: Confirms diagnosis (45,X or mosaicism).
• Cardiac imaging: Echocardiogram or MRI at baseline and repeated surveillance.
• Endocrine screen: FSH/LH (raised), oestradiol (low), thyroid function tests, glucose tolerance, and bone density scans.
• Renal ultrasound: Horseshoe kidney and other anomalies in ~30% of cases.

⚕️ Management

• Growth Hormone Therapy: Early initiation can increase final height by 5–10 cm.
• Oestrogen Replacement: Begin around age 12–14 to induce puberty; later add progesterone for cycle control and endometrial protection.
• Fertility & Pregnancy: Specialist reproductive counselling; donor oocyte IVF possible but pregnancy carries high risk of aortic dissection – needs pre-conception cardiac review.
• Gonadectomy: Essential in 45,X/46,XY mosaics due to risk of gonadoblastoma.
• Multidisciplinary care: Endocrinology, cardiology, audiology, nephrology, and psychology input.
• Psychosocial support: Tailored educational help and counselling for self-esteem and social integration.

📌 Prognosis

With modern endocrine replacement and cardiac monitoring, life expectancy is near-normal. Major morbidity arises from aortic disease, osteoporosis, and infertility. Quality of life can be excellent with early diagnosis, proactive management, and strong psychosocial support.

📚 References

• Turner Syndrome – Clinical Review, Nature Reviews Endocrinology
• NHS UK – Turner Syndrome