Williams-Beuren syndrome: diagnosis by polymorphic markers

Area of Science:

• Genetics
• Molecular Biology
• Clinical Medicine

Background:

• Williams-Beuren syndrome (WBS) is a genetic disorder caused by a microdeletion in the 7q11.23 region.
• Connective tissue abnormalities in WBS are often linked to haploinsufficiency of the ELN gene.

Purpose of the Study:

• To evaluate a polymerase chain reaction (PCR) assay with three polymorphic markers for detecting the WBS microdeletion.
• To compare clinical features in patients with and without the microdeletion.

Main Methods:

• Thirty-two WBS patients were assessed using clinical criteria.
• Three polymorphic markers (D7S1870, ELN 17/exon 18, Hei 1.3/1.4) were employed to detect heterozygosity in the 7q11.23 region.
• Statistical analysis compared clinical features between groups with and without the microdeletion.

Main Results:

• The polymorphic markers were informative in 78% of cases, with D7S1870 being the most effective.
• The microdeletion was detected in 56% of patients.
• An overfriendly personality and hyperacusis showed statistically significant higher frequency in the microdeletion group.

Conclusions:

• Polymorphic marker PCR assays offer a viable alternative for molecular diagnosis of WBS, especially where fluorescence in situ hybridization (FISH) is unavailable.
• Specific WBS clinical features, including personality and auditory traits, are significantly associated with the presence of the 7q11.23 microdeletion.