Screening of 22q11.2DS Using Multiplex Ligation-Dependent Probe Amplification as an Alternative Diagnostic Method

Area of Science:

• Genetics
• Molecular Biology
• Medical Diagnostics

Background:

• 22q11.2 deletion syndrome (22q11.2DS) is a common genetic disorder.
• It is frequently associated with congenital heart defects (CHDs).
• Genomic rearrangements in the 22q11.2 region cause variable phenotypes.

Purpose of the Study:

• To determine the incidence of 22q11.2DS in patients with CHDs.
• To evaluate diagnostic methods for 22q11.2DS.

Main Methods:

• Echocardiography confirmed CHDs in 42 patients.
• Fluorescence in situ hybridization (FISH) was used for initial screening.
• Multiplex ligation-dependent probe amplification (MLPA) served as a confirmatory test.

Main Results:

• 22q11.2DS was identified in 2 out of 42 CHD cases (4.76%).
• Both positive cases presented with conotruncal heart defects.
• MLPA demonstrated superiority in detecting deletions and duplications within and outside the 22q11.2 locus.

Conclusions:

• The incidence of 22q11.2DS among CHD patients on Malaysia's east coast is 0.047%.
• MLPA is a cost-effective and scalable method for diagnosing 22q11.2DS.
• MLPA can be routinely implemented for deletion syndrome diagnosis.