113  Turner’s Syndrome

Author

Dr. Betty Nkansah Osei Mensah

113.1 Definition

It is defined as a combination of peculiar phenotypic features with either a complete or partial absence of the second X chromosome. It is one the most common chromosomal abnormalities, occurring in approximately 1 in 1,500 to 2,500 live-birth females.

113.2 Genetics

About half the patients with Turner syndrome have 45,X chromosomal complement. The single X chromosome is of maternal origin in 80%, thus the missing X is usually of paternal origin. A similar clinical feature is seen in 46,XXiq karyotype and mosaicism (45,X/ 46, XX). Deletion of the SHOX gene (a gene thought to be important in controlling growth in children) is a consistent finding in Turner syndrome. A similar skeletal phenotype is seen in Leri-Weill dyschondrosteosis.

113.3 Clinical Features

  • At birth: Low birthweight Decreased birth length, Lymphedema of hands and feet, Loose skinfolds at the nape.
  • During childhood into early adolescence: Short stature, webbed neck, low posterior hairline, epicanthal folds, posteriorly rotated ears, high arched palate, micrognathia, shield chest, cubitus valgus, short 4th metacarpal bone, and hyperconvex fingernails, normal mental intelligence (except in mathematics).
  • Late adolescence into adulthood: Delayed puberty. Adrenarche occurs at a normal age and delayed breast development but will completely be absent if ovarian failure occurs before puberty. Primary or secondary amenorrhoea occurs with ovarian failure.

113.4 Associations

  • Ovarian dysgenesis: The normal fetal ovary contains about Seven million oocytes. However, these begin to disappear rapidly after the 5th month of gestation. At birth, there are only 2 million and by age 2 almost all oocytes are depleted.
  • Cardiac defects: Bicuspid aortic valve (33-50%), Coarctation of the Aorta (20%), Aortic stenosis, Mitral valve prolapse, Partial anomalous pulmonary venous drainage.
  • Renal malformation: Seen in 25-50%. They include horseshoe kidneys, double collecting systems Pelvic kidneys, and the Complete absence of one kidney.
  • Others: Autoimmune thyroid disease (10-30%). Inflammatory Bowel Disease and Celiac disease (screening is recommended because the risk of celiac disease is increased in Turner syndrome (4-6%). Recurrent otitis media (75%), resulting in sensorineural hearing deficits. Increased risk of Gonadoblastoma, therefore prophylactic gonadectomy is recommended even in the presence of MRI or CT scan evidence.

113.5 Investigation

  • Genetic testing in all females with short stature and other related clinical features.
  • Echocardiogram to screen for cardiac defects.
  • Abdominopelvic ultrasound scan to assess the kidneys and the ovaries. -
  • Plasma levels of follicle-stimulating hormone (FSH) are markedly raised while the are low levels of estradiol.
  • Transglutaminase immunoglobulin A antibodies to rule in or out Celiac disease.
  • Thyroid peroxidase and thyroglobulin antibodies should be checked periodically to detect autoimmune.

113.6 Treatment

  • Recombinant human growth hormone helps with height velocity.
  • Estrogen replacement therapy for the development of sexual characteristics.
  • Psychological support is very crucial for the management of patients; to help them accept diagnosis and treatment modalities.

113.7 Complications

  • Hypertension
  • Abnormal glucose tolerance and insulin resistance
  • Infertility
  • Sensorineural hearing loss from recurrent bilateral otitis media

113.8 Counselling

  • There should be genetic screening for couples or individuals with Turner syndrome.
  • There is currently no cure and treatment options are focused on symptomatic management, in a multidisciplinary team approach.

113.9 Review Schedule

Birth – 1 Month

  • Confirm diagnosis with karyotype
  • Full physical examination (check for webbed neck, lymphedema)
  • Echocardiogram to assess for:
    • Coarctation of the aorta
    • Bicuspid aortic valve
  • Renal ultrasound to detect congenital anomalies
  • Assess feeding, weight gain, and growth
  • Begin Turner-specific growth charting
  • Referrals:
    • Pediatric cardiology
    • Pediatric nephrology
    • Genetic counseling

1 – 6 Months

  • Monitor growth and development
  • Repeat cardiac evaluation if abnormalities found
  • Thyroid function test (TSH and T4)
  • Hearing screen
  • First ophthalmologic (eye) exam
  • Monitor for:
    • Feeding difficulties
    • Constipation
  • Referrals:
    • Endocrinologist
    • Audiologist
    • Ophthalmologist

6 – 12 Months

  • Track developmental milestones
  • Monitor growth using TS-specific charts
  • Repeat hearing test if needed
  • Screen for recurrent otitis media
  • Begin early intervention if developmental delays are noted
  • Referral to ENT if frequent ear infections

1 – 2 Years

  • Annual thyroid function testing
  • Monitor growth velocity
  • Repeat cardiac evaluation if previously abnormal
  • Begin dental evaluation
  • Continue hearing and speech assessment
  • Consider initiating Growth Hormone Therapy (GH) around 2–5 years
  • Referral to:
    • Speech therapist
    • Endocrinologist

2 – 5 Years

  • Measure height and weight every 3–6 months
  • Annual:
    • Hearing test
    • Vision exam
    • Thyroid function
  • ENT review for chronic ear infections
  • Cardiac re-evaluation every 3–5 years
  • Continue/Start Growth Hormaone therapy.
  • Regular dental check-ups every 6 months
  • Begin developmental and learning support if needed

5 – 10 Years

  • Annual:
    • Thyroid, vision, hearing, dental exams
  • Bone age x-ray every 1–2 years
  • Monitor for signs of puberty
  • Screen for learning and behavioral issues
  • Check blood pressure annually
  • Continued GH therapy
  • Referrals:
    • Psychologist or special educator
    • Neurodevelopmental team for learning difficulties

10 – 13 Years (Early Adolescence)

  • Assess for pubertal development
    • If absent by 12–13 years, begin estrogen replacement
  • Annual:
    • Thyroid
    • Hearing
    • Vision
    • Liver function and lipid profile
  • DEXA scan if available to assess bone health
  • Cardiac MRI or echocardiogram if CHD present
  • Continue GH if appropriate
  • Begin psychosocial counseling

13 – 16 Years (Mid-Adolescence)

  • Continue estrogen therapy

    • Introduce progesterone if uterus is present

  • Annual:

    • Thyroid
    • Liver function
    • Lipid profile

  • Discuss:

    • Fertility options
    • Sexual health education

  • Monitor for emotional well-being, social adjustment

  • Referrals:

    • Gynecologist or adolescent endocrinologist
    • Mental health support
    • Career and vocational guidance