Predicting 22q11.2 deletion syndrome: a novel method using the routine full blood count

Area of Science:

• Genetics and Genomics
• Hematology
• Pediatric Cardiology

Background:

• 22q11.2 deletion syndrome affects nearly 1 in 3000 individuals, often associated with DiGeorge Syndrome and congenital heart disease.
• Diagnosis is critical due to impaired immune function, risk of fatal graft-versus-host disease from non-irradiated blood, and potential hypocalcaemia.
• Current diagnostic methods may not be rapid enough for timely clinical decisions.

Purpose of the Study:

• To investigate if Mean Platelet Volume (MPV), a routine blood count parameter, can serve as a rapid indicator for 22q11.2 deletion.
• To assess the utility of MPV as a screening tool in pediatric patients with congenital heart disease.

Main Methods:

• Retrospective case-control cohort study.
• Analysis of MPV and 22q11.2 deletion status in 166 pediatric patients undergoing cardiac surgery.
• Utilized receiver operating characteristic (ROC) curve analysis to evaluate MPV's predictive accuracy.

Main Results:

• Twenty children (12%) were positive for 22q11.2 deletion.
• Median MPV was significantly higher in 22q11.2 positive patients (10.9 fL) compared to negative patients (8.6 fL) (p<0.001).
• MPV demonstrated good predictive accuracy with an Area Under the Curve (AUC) of 0.85 on ROC analysis.

Conclusions:

• MPV is a cost-effective, non-invasive screening test for 22q11.2 deletion in children with congenital heart disease.
• An MPV threshold of >10 fL predicts 22q11.2 deletion with 89.7% specificity.
• This finding supports prompt clinical decisions regarding irradiated blood products and close monitoring for hypocalcaemia.