Brain abnormalities, neurodegeneration, and dysosteosclerosis (BANDDOS) is an autosomal recessive disorder characterized by brain abnormalities, progressive neurologic deterioration, and sclerotic bone dysplasia similar to dysosteosclerosis (DOS). The age at onset is highly variable: some patients may present in infancy with hydrocephalus, global developmental delay, and hypotonia, whereas others may have onset of symptoms in the late teens or early twenties after normal development. Neurologic features include loss of previous motor and language skills, cognitive impairment, spasticity, and focal seizures. Brain imaging shows periventricular white matter abnormalities and calcifications, large cisterna magna or Dandy-Walker malformation, and sometimes agenesis of the corpus callosum (summary by Guo et al., 2019).

Brunet-Wagner neurodevelopmental syndrome (BRUWAG) is an autosomal recessive disorder characterized by infantile hypotonia and severely impaired development affecting both motor and cognitive skills. Affected individuals either do not achieve independent ambulation or walk with an unsteady gait; those who walk may lose the ability due to spasticity of the lower limbs. They have absent language, poor or absent social skills, and behavioral abnormalities. Most have variable ocular findings, including nystagmus, strabismus, optic atrophy, myopia, or hypermetropia (summary by Brunet et al., 2020 and Samra et al., 2021).