The identification of pathogenic mutations in Ras analog in brain 39B (RAB39B) and Ras analog in brain 32 (RAB32) that cause Parkinson's disease (PD) has highlighted the emerging role of protein trafficking in disease pathogenesis.
We did not find any coding variants or previously reported mutations, suggesting that RAB39B mutations are not a common cause of early-onset or familial PD in our Taiwanese population.
On the other hand, nonsense and missense mutations of the X-chromosome localized RAB39B were shown to underlie X-linked intellectual disability (ID) in male patients with early-onset PD.
RAB39B pathogenic variants cause X-linked Parkinsonism associated with Intellectual Disability, known as Waisman syndrome, a very rare disorder that has been mainly identified through exome sequencing in large Parkinson's disease cohorts.
Further characterization of normal and aberrant RAB39B function might elucidate important mechanisms underlying neurodegeneration in PD and related disorders.