title: Allelic variations at the haploid TBX1 locus do not influence the cardiac phenotype in cases of 22q11 microdeletion.
abstract: Microdeletion at the 22q11 locus is characterised by a high clinical variability. Congenital heart defects (CHD) are the most life-threatening manifestations of the syndrome and affect approximately 50% of patients carrying the deleted chromosome 22. The causes of this phenotype variability remain unknown although several hypotheses have been raised. It has been suggested that allelic variations at the haploid locus could modify the phenotypic expression. Regarding this hypothesis, TBX1 was thought to be a major candidate to the cardiac phenotype or its severity in patients carrying the 22q11 microdeletion. A mutational screening was performed in this gene, in a series of 39 deleted patients, with and without CHD. The results indicate that mutations in TBX1 are not likely to be involved in the cardiac phenotype observed in del22q11 patients.
authors.affiliation: Laboratoire de Genetique Moleculaire, Departement de Genetique Medicale, Hôpital d'Enfants de la Timone, 264, rue Saint-Pierre, 13385 Marseille cedex 5, France. marie-antoinette.voelckel@ap-hm.fr
authors.forename: Marie-Antoinette
authors.initials: MA
authors.lastname: Voelckel
authors.forename: Lydie
authors.initials: L
authors.lastname: Girardot
authors.forename: Bernard
authors.initials: B
authors.lastname: Giusiano
authors.forename: Nicolas
authors.initials: N
authors.lastname: Levy
authors.forename: Nicole
authors.initials: N
authors.lastname: Philip
mesh_terms: D000483:Alleles; D002892:Chromosomes, Human, Pair 22 / Q000648:ultrastructure*; D004252:DNA Mutational Analysis; D005091:Exons / Q000235:genetics; D014644:Genetic Variation; D006330:Heart Defects, Congenital / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D010641:Phenotype; D017384:Sequence Deletion; D020825:T-Box Domain Proteins / Q000235:genetics*
chemical_list: D020825:T-Box Domain Proteins; C108625:TBX1 protein, human