The gene AP3B2 is located on chromosome 15q25.2 and encodes the subunit β3B of the AP3 complex, which plays a role in intracellular vesicle trafficking to lysosomes and lysosome-related organelles. The subunit β3B is exclusively expressed in neurons and seems to engage in neuron-specific sorting and vesiculation processes. Homozygous or compound heterozygous variants in AP3B2 cause an autosomal recessive neurological disorder primarily characterized by early-onset epileptic encephalopathy.
Assoum et al. (2016) reported homozygous or compound heterozygous splice site, frameshift, or nonsense mutations in the AP3B2 gene in 12 patients from 8 unrelated families. Anazi et al. reported a homozygous truncating mutations in the AP3B2 gene in 2 patients born in consanguineous families.
Diagnostic testing is usually performed via multi-gene panel and exome / genome sequencing.
AP3B2