Turner syndrome

För svenska - se Turners syndrom
 

BACKGROUND

Turner syndrome is the most common sex chromosome aberration in women. The prevalence is 1/2500 born girls. Turner syndrome is totally or partially lacking one of the two female sex chromosomes: (monosomy) 45,X instead of 46,XX, or (mosaicism) 45,X/46,XX. Iso-, ring- or Y-chromosome fragments can also occur.

There are around 1800 girls/women with Turner syndrome in Sweden (female population of 5 million) of whom half are clinically known. Hence, some cases are undetected and can possibly be explained by the fact that many women are well-being and have only few stigmata, especially those with a mosaicism karyotype.

Mean age at diagnosis is approximately 10 years for monosomy 45,X, iso-, ring- and Y-fragment and 18 years for mosaicism 45,X/46,XX.


Short history

Turner syndrome was named by the American physician Henry Turner, who worked in Oklahoma, USA and in 1938 described 7 young women with hypogonadism, short stature, and webbed neck. Not until 1950 was the syndrome associated with the chromosomal aberration 45,X. The Swedish genetician Jan Lindsten described the mosaicism in 1961.

In Sweden we started the Swedish Turner Academy in 1993, an interdisciplinary network of interested specialists who examine and monitor girls/women with Turner syndrome at all university hospitals at 1 to 5 year intervals. The interannual controls are performed in their home cities and by their ordinary physicians.

The Swedish national guidelines for Turner syndrome were first published in 2000 (“Vårdprogram” revised 2014) and the international guidelines by The Turner Syndrome Study Group have been regularly revised (Saenger et al 2001, Bondy et al 2007, Gravholt et al 2017)

DIAGNOSIS

Turner syndrome is usually diagnosed at any of the following three times in life:

• At birth due to swollen hands, feet and neck and/or possible congenital heart disease or aortic abnormalities.
   
• During growth due to short stature, lack of puberty and primary amenorrea.
   
• In adulthood due to infertility or secondary amenorrea/premature menopause.

Suspect Turner syndrome when congenital heart disease, short stature, lack of puberty, secondary amenorrea, hypothyroidism or impaired hearing are present! Request a chromosome analysis!

CLINICAL SIGNS

External stigmata

• Short stature
• Webbed neck
• Narrow palate
• Increased intermamillar distance
• Low hairline
• Keloid formation in scars
• Epicantus fold (fold in the inner eye angle)
• Small mouth
• Outstanding ears
• Low sitting ears
• Impaired hearing (hearing aid)
• Impaired vision (glasses)
• Strabismus
• Mulitple naevi
• Short neck
• Short metacarpale IV
• Hyperteleorism (increased distance between the eyes)
• Broad chest
• Cubitus valgus (out rotated underarms distal of the elbows)
• Micrognatia (small lower cheak)
• Scoliosis

Common clinical signs

• Hypertension and congenital heart aberrations are present in around 20 % of cases and consist mainly of coarctatio aortae and bicuspid aortic valve.
   
• High risk for aortic dissection at young age, median age 32 years. Congenital heart disease, hypertension, aortic dilation and 45,X are predisposing factors.
   
• Hypothyroidism, especially of autoimmune origin with elevated thyroid peroxidase antibodies (TPO), are present in 30-50 % independent of karyotype.
   
• Pathological liver enzymes, especially elevated gamma-GT, are present in about 50 % but have not been associated with any serious liver disease during follow-up. The pathological liver enzymes have been shown to correlate with serum total cholesterol independently of body weight and waist/hip circumference.
   
• Recurrent otitis are common. Many have had problems with otitis as children.
   
• Sensorineural hearing impairment is present in around 25 % and often at a young age. Women with Turner syndrome suffer from presbyacusis (age related hearing impairment) around 10-15 years earlier than women without Turner syndrome.
   
• Women with Turners syndrome above 40 years of age have a higher prevalence of fractures than women of similar age in the population. Younger women with Turner syndrome who have received growth hormone have fairly similar bone mineral density and fracture prevalence as women in general.
   
• Impaired body balance is strongly associated with hearing impairment and both constitute a social handicap.
   
• Social isolation, mainly related to hearing impairment, is more common in women with Turner syndrome. In spite of this, these women study and work to a similar extent as those in the general population.

DIFFERENTIAL DIAGNOSES

• Pituitary insufficiency
• Hyperprolactinemia
• Autoimmune premature ovarian insufficiency
• Autoimmune hypothyroidism
• Retarded growth due to celiac disease

EXAMINATIONS

• Chromosomal analysis should be performed to verify the diagnosis. The analysis is performed on lymphocytes. Request Fluorescence In Situ Hybridization (FISH)-analysis to examine the degree of possible mosaicism. The FISH-analysis can also be performed on buccal smear and fibroblasts via dermal biopsy.
   
• Blood samples for FSH and LH (both elevated in Turner syndrome) should be taken to verify primary ovarian insufficiency. These gonadotropins are often inhibited by estrogen hormone replacement. Prolactin is checked initially.
   
• Examination of the heart and aortae is important. An echocardiography (UCG) and a magnetic resonance imaging (MRI) scan should be performed. Check for bicuspid aortic valve, coarctatio aortae and the width of the aortae (must be related to body size). UCG can be repeated every 5^th to every 10^th year during the adulthood. The frequency for MRI-scans depends on possible aberrations. Regular examinations are performed by a cardiologist at a special Grown Up Congenital Heart disease (GUCH)-clinic is recommended if cardiac or vessel abnormalities are detected. MRI must be performed before pregnancy induction and repeated UCG or MRI during pregnancy is advised. Pregnancy is not recommended if cardiac and/or vessel abnormalities are present or have been operated.
   
• Blood pressure is checked annually. Treatment is started irrespective of age if elevated blood pressure is present. Blood pressure lowering agents should be initiated if the aorta is dilated or if the patient has or has been operated on due to coarctatio and/or aortic dissection. The target level recommendation for blood pressure treatment should be lower than the limits according to guidelines in the general population, especially if aortic dilation or other cardiac or vessel aberration is present.
   
• Ultrasound of the kidneys is recommended initially. Horse shoe kidney, agenesis, double ureters can be present.
   
• Height and body weight are checked annually. Waist-hip circumference can be measured every 5^th year. Overweight and obesity should be avoided.
   
• Hearing test, audiometry, should be done every 5^th year.
   
• Bone measurement, preferably with DXA, should be performed after transfer to the adult clinic or when the Turner syndrome is diagnosed in adulthood. Continued bone measurement is done if fractures occur and if any bone specific agents are initiated. Guidelines for such treatment are similar to the population in general. T-score is used even if the bone mineral density is not adjusted for height in women with Turner syndrome.
   
• Remittance to a dentist, logopedian, eye specialist, dermatologist, plastic surgeon, orthopedic specialist, psychologist etc. is done when needed.
   
• Note: The risk for keloid in scars is high, especially on the face and upper body after surgical incisions. Webbed neck can be operated on by a plastic surgeon.
   
• Blood sampling yearly: Thyroid function (free T4, TSH, TPO) and hemoglobin. Hypothyroidism can also develop without elevation of TPO, but the risk is higher when TPO is elevated.
   
• Sampling and examinations every 5^th year:
  - Thyroid function (free T4, TSH, TPO)
  - Fasting glucose
  - Lipids (cholesterol, HDL, triglycerides)
  - Liver enzymes (ASAT, ALAT, ALP, bilirubin, gamma-GT)
  - Sodium, potassium, calcium and creatinine
  - Hemoglobin
  - Vitamin B12, folic acid
  - 25-OH-vitamin D
  - Blood pressure
  - Height, body weight and waist-hip circumference
  - UCG
  - DXA, could be performed more seldom if previously normal and no fracture has occured
  - Audiometry
  - Examination by a gynecologist
  - Examination by an endocrinologist
   
• Targeted extended sampling is performed if something indicates further examination. Ultrasound of the liver can be performed if the liver enzymes increase. Gastroscopy should be performed and celiac disease determined if hemoglobin, vitamin B12, iron, calcium and possibly 25-OH vitamin D are low. Antibodies for gluten can be checked.

TREATMENT AND FOLLOW-UP

Around 90 % of women below 35 years of age with clinically known Turner syndrome in Sweden have received modern treatment consisting of growth hormone, androgen and followed by pubertal induction with estrogen.

Growth hormone treatment due to short stature was introduced in Sweden 1988. Today, continuous estrogen hormone replacement is given to nearly 100 % of women with diagnosed Turner syndrome. Transition to the adult clinic primarily to a gynecologist for continuous estrogen prescription but also to a specialist in internal medicine, endocrinology, cardiology, or general practitioner is needed if any comorbidity, as mentioned above is present. The estrogen hormone replacement, handled by a gynecologist annually, can be continued life long or possibly until the patient wants to reduce the dose or alternatively continue to the age of corresponding menopause for women without Turner syndrome. Breast cancer is very rare in Turner syndrome. Mammography is performed according to guidelines for women in the population. Estrogen treatment doses are shown in the Pediatric and the Gynecological chapters, respectively, in the Guidelines below (Vårdprogram).

If a Y-fragment is present gonadectomy is recommended due to the risk for gonadoblastoma. Pregnancy induction and possible oocyte donation, permitted in Sweden since 2003, can be discussed with the gynecologist. MRI of the heart/aorta must be performed before any pregnancy induction is planned or initiated! Pregnancy is not recommended if cardiac and/or vessel abnormalities are present or have been operated.

Blood sampling regarding thyroid function yearly and levothyroxine substitution is initiated if hypothyroidism is present, lipid lowering agents can be considered if pathologically elevated lipids are present in spite of euthyroidism. Possible diabetes mellitus, osteoporosis and fractures should be dealt with according to current guidelines in the population.

General advice regarding diet and physical activity should be given to avoid overweight, obesity and osteoporosis.

With modern treatment and follow-up by a physician with special knowledge and interest in Turner syndrome most women with the syndrome live a fairly healthy life. Life expectancy is around 10-15 years shorter than in other women in the general population – aortic dissection at young age is the most feared complication.

ICD-10

Mosaicism, 45,X/46,XX eller XY Q96.3
Mosaicism, 45,X/andra cellinjer med avvikande könskromosom Q96.4
Karyotyp 46,X iso Q96.1
Karyotyp 46,X med avvikande könskromosom, förutom iso Q96.2
Andra varianter av Turners syndrom Q96.8
Turners syndrom, ospecificerat Q96.9
Karyotyp 45,X Q96.0

 

References

Vårdprogram vid Turners syndrom 2014 (PDF)

Pediatriska delen av vårdprogrammet 2013 (PDF)

Saenger P, Wikland KA, Conway GS, Davenport M, Gravholt CH, Hintz R, Hovatta O, Hultcrantz M, Landin-Wilhelmsen K, Lin A, Lippe B, Pasquino AM, Ranke MB Rosenfeld, Silberbach M; Fifth International Symposium on Turner Syndrome. Recommendations for the diagnosis and management of Turner syndrome. J Clin Endocrinol Metab 2001;86:3061-9. Länk

Bondy CA for the Turner Syndrome Consensus Study Group. Clinical Practice Guidelines. Care of girls and women with Turner Syndrome: A guideline of the Turner Syndrome Study Group. J Clin Endocrinol Metab 2007;92:10-25. Länk

El-Mansoury M. M. Turner syndrome. Relation between genotype and phenotype and long-term follow-up studies. Academic dissertation. University of Gothenburg 2009. ISBN 978-91-628-7917-4 (Länk).

Bryman I, Sylvén L, Berntorp K, Innala E, Bergström I, Hanson C, Oxholm M, Landin-Wilhelmsen K. Pregnancy rate and outcome in Swedish women with Turner syndrome. Fertil Steril 2011; 95:2507-10. Länk

Hagman A, Källén K, Bryman I, Landin-Wilhelmsen K, Barrenäs M-L, Wennerholm U-B. Morbidity and mortality after childbirth in women with Turner karyotype. Hum Reprod 2013;28:1961-73. Länk

Gravholt CH et al. Clinical practice guidelines for the care of girls and women with Turner syndrome: proceedings from the 2016 Cincinnati International Turner Syndrome Meeting. Eur J Endocrinol. 2017 Sep;177(3):G1-G70. Länk

Krantz E, Landin-Wilhelmsen K, Trimpou P, Bryman I, Wide U. Health Related Quality of Life of Women with Turner Syndrome and the Influence of Growth Hormone Therapy: A 20-Year-Follow-up. J Clin Endocrinol Metab. 2019;104(11):5073-83. Länk

Thunström S, Krantz E, Thunström E, Hanson C, Bryman I, Landin-Wilhelmsen K. Incidence of Aortic Dissection in Turner Syndrome—A 23-Year Prospective Cohort Study. Circulation. 2019 Jun 11;139(24):2802-04. Länk