What is the evaluation process for Turner syndrome?

Evaluation Process for Turner Syndrome

The evaluation for Turner syndrome requires TTE and cardiac MRI at the time of diagnosis to assess for cardiovascular abnormalities, which are present in approximately 50% of patients and significantly impact mortality risk. 1

Initial Diagnostic Evaluation

• Karyotype analysis is the definitive diagnostic test for Turner syndrome, which affects 1 in 2,500 liveborn girls and results from complete or partial loss of the second X chromosome 2, 3
• Transthoracic echocardiography (TTE) and cardiac MRI should be performed at diagnosis to evaluate for bicuspid aortic valve (BAV), aortic root/ascending aortic dilation, aortic coarctation, and other congenital heart defects 1
• Physical examination should assess for characteristic features including short stature, webbed neck, and delayed puberty 4, 5
• For patients ≥15 years old, calculate the aortic size index (ASI) by dividing the maximal aortic diameter (cm) by body surface area (m²) to assess aortic dissection risk 1
• In children <15 years old, a Turner syndrome-specific z-score should be used to assess for aortic dilation 1

Laboratory Testing

• Complete blood count to detect mild-moderate thrombocytopenia and cytopenias 6
• Thyroid-stimulating hormone to screen for autoimmune thyroid disease 6
• Calcium and magnesium levels with attention to pH-corrected ionized calcium 6
• Renal function tests including creatinine 6
• Lipid profile to assess cardiovascular risk 6
• Glucose and HbA1c to screen for diabetes 6
• Parathyroid hormone if calcium abnormalities are detected 6

Cardiovascular Surveillance Protocol

For patients without risk factors for aortic dissection:

• Children: TTE or MRI every 5 years 1
• Adults: TTE or MRI every 10 years 1
• Imaging before planning pregnancy 1

For patients with ASI >2.3 cm/m²:

• At least annual surveillance imaging of the aorta 1

For patients with risk factors for aortic dissection (BAV, aortic coarctation, hypertension):

• Surveillance frequency depends on aortic diameter, ASI, and aortic growth rate 1
• More frequent monitoring is required as ASI approaches 2.5 cm/m² 1

Surgical Intervention Criteria

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

Additional Evaluations

• Educational evaluation in early childhood to identify potential attention-deficit or nonverbal learning disorders 7
• Assessment for ovarian dysgenesis and hypergonadotropic hypogonadism 2, 3
• Screening for other associated conditions including osteoporosis and autoimmune disorders 2, 7

Follow-up Testing Schedule

• Low cardiovascular risk: Laboratory tests every 2-3 years 6
• Moderate cardiovascular risk: Laboratory tests annually 6
• High cardiovascular risk: Laboratory tests every 6-12 months 6

Common Pitfalls to Avoid

• Failing to adjust aortic measurements for body size when interpreting cardiovascular risk 6
• Neglecting to monitor for diabetes and dyslipidemia, which have higher prevalence in Turner syndrome 6
• Using standard reference ranges without considering Turner-specific normative data 6
• Diagnostic delay is common (average age at diagnosis is around 15 years), which can lead to missed opportunities for early intervention 2, 3
• Underestimating the risk of aortic dissection in patients with Turner syndrome, especially those with small body size 1