Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph disease (MJD), is characterized by progressive cerebellar ataxia and variable findings including pyramidal signs, a dystonic-rigid extrapyramidal syndrome, significant peripheral amyotrophy and generalized areflexia, progressive external ophthalmoplegia, action-induced facial and lingual fasciculations, and bulging eyes. Neurologic findings tend to evolve as the disorder progresses.

Developmental and epileptic encephalopathy-49 (DEE49) is a severe autosomal recessive neurologic disorder characterized by onset of seizures in the neonatal period, global developmental delay with intellectual disability and lack of speech, hypotonia, spasticity, and coarse facial features. Some patients may have brain calcifications on imaging (summary by Han et al., 2016). For a general phenotypic description and a discussion of genetic heterogeneity of DEE, see 308350.