title: Three new cases of terminal deletion of the long arm of chromosome 7 and literature review to correlate genotype and phenotype manifestations.
abstract: Partial monosomy of the long arm of chromosome 7 has been characterized by wide phenotypic manifestations, but holoprosencephaly (HPE) and sacral agenesis have frequently been associated with this chromosomal deletion. A clear relationship between genotype and phenotype remains to be defined in the 7q deletion syndrome. Three patients (1, 2, and 3) were investigated with 7q terminal deletion and compared with similar deletion cases in the literature in order to stratify the phenotypes associated with 7q35 and 7q36 terminal deletion patients. Patients 1, 2, and 3 were carrying a de novo terminal deletion at bands 7q36.2, 7q35, and 7q36.1, respectively. In patient 3, a small Xq28 duplication was also identified by array-CGH. Our patients presented with heterogeneous phenotypic manifestations, which could imply the possible role of environmental factors (multifactorial inheritance), structural variations in the non-coding regions, penetrance, and/or polymorphism. The varying length of deletion was also taken into account. Growth retardation was the most frequent symptom found in both 7q35 and 7q36 patients we reviewed. The occurrence of HPE and sacral malformation together was seen in less than 10% of the reviewed cases in both kinds of deletion. HPE was associated mainly in cases with an unbalanced translocation.
authors.affiliation: Division of Genetics, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Seemi
authors.initials: S
authors.lastname: Ayub
authors.affiliation: Division of Genetics, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.|Manitoba Institute of Cell Biology (MICB), CancerCare Manitoba (CCMB), The Genomic Centre for Cancer Research and Diagnosis (GCCRD), The University of Manitoba, Winnipeg, Manitoba, Canada.|Laboratory of Hematology and Immunology, National Centre of Blood Transfusion of Dakar (CNTS), The Cheikh Anta Diop University of Dakar (UCAD), Dakar Fann, Senegal.
authors.forename: Macoura
authors.initials: M
authors.lastname: Gadji
authors.affiliation: Division of Genetics, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Kada
authors.initials: K
authors.lastname: Krabchi
authors.affiliation: Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Côté
authors.affiliation: Centre de Recherche du Centre Hospitalier Universitaire de Québec (CHUQ), Division of Medical Genetics, Unité de Diagnostic Prénatal, Faculty of Medicine, Laval University, Quebec City, Québec, Canada.
authors.forename: Jean
authors.initials: J
authors.lastname: Gekas
authors.affiliation: Division of Genetics, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.|Division of Medical Genetics, CHUQ, Faculty of Medicine, Laval University, Quebec City, Québec, Canada.
authors.forename: Bruno
authors.initials: B
authors.lastname: Maranda
authors.affiliation: Division of Genetics, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.|Division of Medical Genetics, CHUQ, Faculty of Medicine, Laval University, Quebec City, Québec, Canada.|Department of Biological Sciences, Faculty of Sciences, Université du Québec à Montréal, Montreal, Québec, Canada.
authors.forename: Régen
authors.initials: R
authors.lastname: Drouin
mesh_terms: D000293:Adolescent; D002648:Child; D002872:Chromosome Deletion; D025063:Chromosome Disorders / Q000175:diagnosis* / Q000235:genetics*; D002897:Chromosomes, Human, Pair 7; D055028:Comparative Genomic Hybridization; D005260:Female; D056726:Genetic Association Studies; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D018895:Microsatellite Repeats; D010641:Phenotype
keywords: 7q deletion; array-CGH; chromosome 7; holoprosencephaly; sacral agenesis