Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
XB-ART-60743
Neurobiol Dis 2024 May 19;:106537. doi: 10.1016/j.nbd.2024.106537.
Show Gene links Show Anatomy links

AP2A2 mutation and defective endocytosis in a Malian family with hereditary spastic paraplegia.

Diarra S , Ghosh S , Cissé L , Coulibaly T , Yalcouyé A , Harmison G , Diallo S , Diallo SH , Coulibaly O , Schindler A , Cissé CAK , Maiga AB , Bamba S , Samassekou O , Khokha MK , Mis EK , Lahkani SA , Donovan FX , Jacobson S , Blackstone C , Guinto CO , Landouré G , Bonifacino JS , Fischbeck KH , Grunseich C .


Abstract
Hereditary spastic paraplegia (HSP) comprises a large group of neurogenetic disorders characterized by progressive lower extremity spasticity. Neurological evaluation and genetic testing were completed in a Malian family with early-onset HSP. Three children with unaffected consanguineous parents presented with symptoms consistent with childhood-onset complicated HSP. Neurological evaluation found lower limb weakness, spasticity, dysarthria, seizures, and intellectual disability. Brain MRI showed corpus callosum thinning with cortical and spinal cord atrophy, and an EEG detected slow background in the index patient. Whole exome sequencing identified a homozygous missense variant in the adaptor protein (AP) complex 2 alpha-2 subunit (AP2A2) gene. Western blot analysis showed reduced levels of AP2A2 in patient-iPSC derived neuronal cells. Endocytosis of transferrin receptor (TfR) was decreased in patient-derived neurons. In addition, we observed increased axon initial segment length in patient-derived neurons. Xenopus tropicalis tadpoles with ap2a2 knockout showed cerebral edema and progressive seizures. Immunoprecipitation of the mutant human AP-2-appendage alpha-C construct showed defective binding to accessory proteins. We report AP2A2 as a novel genetic entity associated with HSP and provide functional data in patient-derived neuron cells and a frog model. These findings expand our understanding of the mechanism of HSP and improve the genetic diagnosis of this condition.

PubMed ID: 38772452
PMC ID: PMC11209852
Article link: Neurobiol Dis


Species referenced: Xenopus tropicalis
Genes referenced: ap2a2 eps15 erlin2 hsp90aa1 neurod2 spg11 spg21 tf

Disease Ontology terms: hereditary spastic paraplegia
OMIMs: SPASTIC PARAPLEGIA 4, AUTOSOMAL DOMINANT; SPG4
References [+] :
Abou Jamra, Adaptor protein complex 4 deficiency causes severe autosomal-recessive intellectual disability, progressive spastic paraplegia, shy character, and short stature. 2011, Pubmed