Copy number variation in Williams-Beuren syndrome: suitable diagnostic strategy for developing countries

Area of Science:

• Genetics
• Molecular Biology
• Clinical Diagnostics

Background:

• Williams-Beuren syndrome (WBS) is a genetic disorder caused by a microdeletion at 7q11.23.
• Key symptoms include supravalvular aortic stenosis, intellectual disability, and distinctive facial features.
• While fluorescence in situ hybridization (FISH) is standard, alternative diagnostic methods are explored.

Purpose of the Study:

• To evaluate the diagnostic utility of microsatellite DNA markers and MLPA for WBS.
• To compare the effectiveness of these methods with existing diagnostic approaches.

Main Methods:

• A cohort of 88 patients with suspected WBS was analyzed.
• Five microsatellite markers (D7S1870, D7S489, D7S613, D7S2476, D7S489_A) and a commercial MLPA kit (P029) were employed.
• Deletion presence, parental origin, and size were assessed.

Main Results:

• Microdeletions consistent with WBS were identified in 72.7% of patients.
• Maternal deletions occurred in 56.3% and paternal in 43.7% of cases.
• Deletion sizes of 1.55 Mb and 1.84 Mb were observed, with no clinical correlation to size or origin.

Conclusions:

• MLPA provides a rapid and cost-effective single-assay option for WBS diagnosis.
• Microsatellite markers can determine deletion size and parental origin.
• Both MLPA and microsatellite markers are effective for WBS deletion detection, offering valuable diagnostic strategies, particularly for resource-limited settings.