TITLE:
Clinical and Molecular Cytogenetic Study of 38 Williams-Beuren Syndrome Tunisian Patients
AUTHORS:
Ines Ouertani, Myriam Chaabouni, Imen Chelly, Lilia Kraoua, Faouzi Maazoul, Mediha Trabelsi, Rym Meddeb, Rafik Boussaada, Hatem Azzouz, Fatma Charfi, Emira Ben Hamida, Ahmed Meherzi, Ridha Mrad, Habiba Bouhamed-Chaabouni
KEYWORDS:
Williams-Beuren Syndrome, FISH, Dysmorphism, Cardiovascular Malformation
JOURNAL NAME:
Open Journal of Genetics,
Vol.4 No.5,
September
12,
2014
ABSTRACT: Background:
Williams-Beuren syndrome (WBS) is a rare multi-system genomic disorder, caused
by 7q11.23 microdeletion with a prevalence of 1/7500 - 1/20,000 live births.
Clinical phenotype includes typical facial dysmorphism (elfin face), mental
retardation associated with a peculiar neuropsychological profile and
congenital heart defects. Other signs are occasional like ocular, skeletal,
renal and dental anomalies. Here in, we present 38 WBS Tunisian patients.
Methods: All patients underwent a genetic consultation and in order to confirm
the clinical diagnosis of WBS, fluorescent in
situ hybridization (FISH) was applied on metaphase spreads using the dual
color locus specific identifier WBS region probe (Vysis probe) that hybridized
to the ELN and LIMK1 loci at 7q11.23 and to control loci D7S486 and D7S522 at
7q31. About 15 to 20 metaphases were analyzed for each case. Results: The mean
age at diagnosis was 4 years and 4 months. All patients showed facial
dysmorphism. 66% (23/35) have cardiovascular anomaly, peripheral pulmonary
stenosis (10/35) is interestingly more frequent than the supravalvular aortic stenosis
(7/35). Various degrees of mental retardation were present and a normal
intelligence was found in three patients. The unique cognitive profile was
found in all patients except one who had autistic disorders. Ocular anomalies
(13/38) were less frequent than described, the skeletal anomalies too (12/38).
Dental malformations were frequent (22/32). Idiopathic hypercalcemia was
present in 50% of children less than one year (2/4). Conclusions: WBS was a
rare disorder, cardinal signs (facial dysmorphism, mental retardation and
cardiovascular defects) were found in our patients in the same proportions than
described. The occasional clinical signs have proportion different of precedent
reported like hypercalcemia, ocular and dental anomalies. The identification of
the different clinical signs in WBS patients permits to establish a strategy of
follow up.