title: Identification of single gene deletions at 15q13.3: further evidence that CHRNA7 causes the 15q13.3 microdeletion syndrome phenotype.
abstract: The 15q13.3 microdeletion syndrome (OMIM #612001) is characterized by a wide range of phenotypic features, including intellectual disability, seizures, autism, and psychiatric conditions. This deletion is inherited in approximately 75% of cases and has been found in mildly affected and normal parents, consistent with variable expressivity and incomplete penetrance. The common deletion is approximately 2 Mb and contains several genes; however, the gene(s) responsible for the resulting clinical features have not been clearly defined. Recently, four probands were reported with small deletions including only the CHRNA7 gene. These patients showed a wide range of phenotypic features similar to those associated with the larger 15q13.3 microdeletion. To further correlate genotype and phenotype, we queried our database of >15,000 patients tested in the Mayo Clinic Cytogenetics Laboratory from 2008 to 2011 and identified 19 individuals (10 probands and 9 family members) with isolated heterozygous CHRNA7 gene deletions. All but two infants displayed multiple features consistent with 15q13.3 microdeletion syndrome. We also identified the first de novo deletion confined to CHRNA7 as well as the second known case with homozygous deletion of CHRNA7 only. These results provide further evidence implicating CHRNA7 as the gene responsible for the clinical findings associated with 15q13.3 microdeletion.
authors: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA. hoppmanchaney.nicole@mayo.edu
authors: N
authors: N
authors: Hoppman-Chaney
authors: K
authors: K
authors: Wain
authors: P R
authors: PR
authors: Seger
authors: D W
authors: DW
authors: Superneau
authors: J C
authors: JC
authors: Hodge
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002872:Chromosome Deletion; D002884:Chromosomes, Human, Pair 15; D005260:Female; D017353:Gene Deletion; D005838:Genotype; D006720:Homozygote; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D010641:Phenotype; D013577:Syndrome; D055815:Young Adult; D064569:alpha7 Nicotinic Acetylcholine Receptor / Q000235:genetics*
chemical_list: C579167:Chrna7 protein, human; D064569:alpha7 Nicotinic Acetylcholine Receptor