JABELS is an autosomal recessive neurodevelopmental disorder characterized by developmental delay and intellectual disability with additional variable features. Patients have onset of symptoms in infancy, but the severity is highly variable. Some patients have social interaction and learn to walk but have an ataxic gait and abnormal movements, such as tremor or dystonia, whereas others do not achieve any motor control and are unable to speak. Additional features may include retinal anomalies, visual impairment, microcephaly, abnormal foot or hand posturing, and kyphoscoliosis; some patients have dysmorphic facial features or seizures. Brain imaging typically shows cerebellar atrophy and hypoplasia of the corpus callosum (summary by et al., 2016 and Bertoli-Avella et al., 2018).

Childhood-onset neurodegeneration with ataxia, tremor, optic atrophy, and cognitive decline (CONATOC) is an autosomal recessive progressive disorder with onset of symptoms in the first decade. Brain imaging may show variable features, including leukoencephalopathy and cerebellar atrophy (summary by Fagerberg et al., 2020).

Dystonia-30 (DYT30) is an autosomal dominant neurologic disorder characterized by the onset of symptoms in the first decades of life. Patients present with oromandibular, cervical, bulbar, or upper limb dystonia, and usually show slow progression to generalized dystonia. Some patients may lose ambulation. A subset of patients may also have neurocognitive impairment, including mild intellectual disability or psychiatric manifestations (summary by Steel et al., 2020). In a review of the pathogenesis of disorders with prominent dystonia, Monfrini et al. (2021) classified DYT30 as belonging to a group of neurologic disorders termed 'HOPS-associated neurologic disorders' (HOPSANDs), which are caused by mutations in genes encoding various components of the autophagic/endolysosomal system, including VPS16.