title: A novel homozygous p.R1105X mutation of the AP4E1 gene in twins with hereditary spastic paraplegia and mycobacterial disease.
abstract: We report identical twins with intellectual disability, progressive spastic paraplegia and short stature, born to a consanguineous family. Intriguingly, both children presented with lymphadenitis caused by the live Bacillus Calmette-Guérin (BCG) vaccine. Two syndromes - hereditary spastic paraplegia (HSP) and mycobacterial disease - thus occurred simultaneously. Whole-exome sequencing (WES) revealed a homozygous nonsense mutation (p.R1105X) of the AP4E1 gene, which was confirmed by Sanger sequencing. The p.R1105X mutation has no effect on AP4E1 mRNA levels, but results in lower levels of AP-4ε protein and of the other components of the AP-4 complex, as shown by western blotting, immunoprecipitation and immunofluorescence. Thus, the C-terminal part of the AP-4ε subunit plays an important role in maintaining the integrity of the AP-4 complex. No abnormalities of the IL-12/IFN-γ axis or oxidative burst pathways were identified. In conclusion, we identified twins with autosomal recessive AP-4 deficiency associated with HSP and mycobacterial disease, suggesting that AP-4 may play important role in the neurological and immunological systems.
authors.affiliation: St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, New York, USA.
authors.forename: Xiao-Fei
authors.initials: XF
authors.lastname: Kong
authors.forename: Aziz
authors.initials: A
authors.lastname: Bousfiha
authors.forename: Abdelfettah
authors.initials: A
authors.lastname: Rouissi
authors.forename: Yuval
authors.initials: Y
authors.lastname: Itan
authors.forename: Avinash
authors.initials: A
authors.lastname: Abhyankar
authors.forename: Vanessa
authors.initials: V
authors.lastname: Bryant
authors.forename: Satoshi
authors.initials: S
authors.lastname: Okada
authors.forename: Fatima
authors.initials: F
authors.lastname: Ailal
authors.forename: Jacinta
authors.initials: J
authors.lastname: Bustamante
authors.forename: Jean-Laurent
authors.initials: JL
authors.lastname: Casanova
authors.forename: Jennifer
authors.initials: J
authors.lastname: Hirst
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Boisson-Dupuis
mesh_terms: D033964:Adaptor Protein Complex 4 / Q000235:genetics* / Q000502:physiology*; D003241:Consanguinity; D004252:DNA Mutational Analysis; D004200:Diseases in Twins; D059472:Exome; D005260:Female; D005808:Genes, Recessive; D020022:Genetic Predisposition to Disease; D006720:Homozygote; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D008297:Male; D009018:Morocco; D009154:Mutation; D009165:Mycobacterium Infections, Nontuberculous / Q000235:genetics*; D010375:Pedigree; D010641:Phenotype; D015419:Spastic Paraplegia, Hereditary / Q000235:genetics*
chemical_list: D033964:Adaptor Protein Complex 4; D007371:Interferon-gamma