title: Phenotypes of AKT3 deletion: a case report and literature review.
abstract: AKT3 (v-akt murine thymoma viral oncogene homolog 3) is located at chromosome 1q44 and encodes a 479 amino acid protein, a member of the protein kinase B (PKB) family. This gene is frequently involved in 1q44 deletion syndrome in patients with microcephaly, intellectual disability, and dysmorphic features. Phenotype and genotype studies of patients with 1q44 deletion syndrome have suggested that deletion of the AKT3 gene is responsible for the microcephaly in these patients. However, the phenotype of pure AKT3 deletion has not been studied. We report on a 1q44 deletion involving only AKT3 in a boy and his father. The boy has microcephaly, hypotonia, feeding difficulties, developmental delay, and minor dysmorphic features. His father does not have microcephaly and is of normal intelligence. We also analyzed the available information on the phenotypes of 13 individuals carrying a pure AKT3 gene deletion identified through literature review and database search. To our knowledge, this is the first report of a paternally inherited pure AKT3 deletion with full clinical description. This is also the first report to suggest that (1) AKT3 deletion is associated with microcephaly and intellectual disability with incomplete penetrance; (2) a pure AKT3 deletion is likely to be inherited in contrast to the larger 1q44 deletions, which are mostly de novo and (3) there seems to be no consistent or characteristic dysmorphism associated with pure AKT3 deletion.
authors.affiliation: Royal Melbourne Hospital, Parkville, Victoria, Australia.
authors.forename: Dayu
authors.initials: D
authors.lastname: Gai
authors.forename: Eric
authors.initials: E
authors.lastname: Haan
authors.forename: Matthew
authors.initials: M
authors.lastname: Scholar
authors.forename: Jillian
authors.initials: J
authors.lastname: Nicholl
authors.forename: Sui
authors.initials: S
authors.lastname: Yu
mesh_terms: D000328:Adult; D002675:Child, Preschool; D002872:Chromosome Deletion; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics*; D017353:Gene Deletion; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010641:Phenotype; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics*
chemical_list: C491754:AKT3 protein, human; D051057:Proto-Oncogene Proteins c-akt
keywords: 1q43-44 deletion; AKT3 deletion; array CGH; developmental delay; microcephaly