Choroid plexus cysts and trisomy 18: risk modification based on maternal age and multiple-marker screening

Area of Science:

• Prenatal diagnostics
• Fetal medicine
• Genetics

Background:

• Choroid plexus cysts (CPCs) are frequently observed during fetal ultrasounds.
• CPCs are associated with an increased risk of chromosomal aneuploidies, particularly trisomy 18.
• The clinical management of isolated CPCs remains debated, especially regarding the necessity of invasive genetic testing.

Purpose of the Study:

• To evaluate the risk of trisomy 18 in fetuses with isolated choroid plexus cysts.
• To determine the optimal criteria for recommending amniocentesis in such cases.
• To integrate maternal age and multiple-marker screening into risk assessment for trisomy 18.

Main Methods:

• Bayesian statistical modeling was employed to calculate trisomy 18 risk.
• Risk assessment incorporated age-related risk figures and CPC incidence in trisomy 18 fetuses.
• The model was further refined using the detection capabilities of multiple-marker screening.

Main Results:

• The risk of trisomy 18 associated with isolated CPCs was calculated across maternal ages 20 to 45.
• The risk of trisomy 18 only approached the threshold for amniocentesis at maternal age 37 years or greater.
• Normal multiple-marker screening results significantly reduced the risk in younger women.

Conclusions:

• In fetuses with isolated CPCs and normal screening, amniocentesis is primarily indicated for women aged 37 and above.
• Maternal age and multiple-marker screening are crucial components in assessing the need for genetic testing.
• This approach helps to personalize risk assessment and avoid unnecessary invasive procedures.