What is the management approach for individuals with mosaic Turner syndrome?

Management Approach for Mosaic Turner Syndrome

The management of individuals with mosaic Turner syndrome requires comprehensive cardiovascular screening, regular surveillance, and targeted interventions based on specific risk factors and clinical manifestations.

Cardiovascular Evaluation and Management

• All patients with mosaic Turner syndrome should undergo baseline cardiovascular imaging with transthoracic echocardiography (TTE) and cardiac MRI at diagnosis to evaluate for bicuspid aortic valve (BAV), aortic root/ascending aortic dilation, aortic coarctation, and other congenital heart defects 1, 2, 3

• For patients ≥15 years old, the aortic size index (ASI) should be calculated (ratio of aortic diameter [cm] to BSA [m²]) to define the degree of aortic dilation and assess the risk of aortic dissection 1, 3

• Surveillance imaging recommendations based on risk stratification:

  • Patients without risk factors for aortic dissection: TTE or MRI every 5 years for children and every 10 years for adults 1, 4
  • Patients with ASI >2.3 cm/m²: At least annual surveillance imaging 1, 4
  • Patients with risk factors for aortic dissection (BAV, aortic coarctation, hypertension): Surveillance frequency depends on aortic diameter, ASI, and aortic growth rate 1, 2

• Surgical intervention criteria:

  • For patients ≥15 years old with ASI ≥2.5 cm/m² plus risk factors for aortic dissection: Surgical replacement of the aortic root, ascending aorta, or both is reasonable 1, 4
  • For those without risk factors but with ASI ≥2.5 cm/m², surgical intervention may be considered 1

• Hypertension should be treated aggressively according to general guidelines 2

• Beta-blockers and/or ARBs may be considered to inhibit aortic growth, similar to management in Marfan syndrome 2

Reproductive Considerations

• A thorough cardiovascular evaluation is mandatory before attempting pregnancy 2, 4

• Pregnancy in Turner syndrome carries substantial risks and requires extensive pre-conception counseling and monitoring 2, 4

• Pregnancy is associated with a higher risk of aortic dissection, especially with pre-existing cardiovascular abnormalities 2, 4

Growth and Endocrine Management

• Short stature is a common feature requiring evaluation and potential growth hormone therapy 5, 6

• Ovarian dysgenesis and hypergonadotropic hypogonadism often necessitate hormone replacement therapy 5, 7

• Screening for other endocrine disorders is essential, including:

  • Type 1 and type 2 diabetes mellitus 5
  • Hypothyroidism 1
  • Osteoporosis 5

Additional Health Surveillance

• Screening for autoimmune disorders is recommended due to increased prevalence 5

• Physical activity should be encouraged but modified based on cardiovascular status and aortic dimensions 4

• Genetic counseling should be offered to all patients 1

Special Considerations for Mosaic Turner Syndrome

• Mosaic 45,X/46,XY individuals may present with a broad spectrum of phenotypes ranging from normal male development to individuals with incomplete sexual differentiation 8

• Males with 45,X/46,XY mosaicism and normal phenotype may go unrecognized until presenting with short stature or other Turner-like features 8

• Boys with otherwise unexplained short stature should be karyotyped routinely, similar to recommendations for short-stature girls 8

Common Pitfalls to Avoid

• Diagnostic delay is common (average age at diagnosis is around 15 years) despite often conspicuous phenotype 5

• Underestimating the risk of aortic dissection, especially in patients with small body size 3

• Failure to use Turner-specific normative data or indexed measurements when assessing aortic dimensions 2, 3

• Inadequate screening for associated conditions and comorbidities that may impact cardiovascular health and overall well-being 1