Neurodevelopmental disorder with language delay and behavioral abnormalities, with or without seizures (NEDLBAS), is characterized by global developmental delay with variably impaired intellectual development apparent from infancy or early childhood. Affected individuals have significant speech delay, and most demonstrate behavioral abnormalities, including autistic features. About half of patients develop seizures, which may be controlled or refractory. More variable features include hypotonia, feeding difficulties, and subtle facial dysmorphism (Schalk et al., 2022).

Autosomal recessive idiopathic basal ganglia calcification-9 (IBGC9) is characterized by a combination of features including ataxia, parkinsonism, headache, and psychiatric and cognitive deficits, with high intrafamilial phenotypic variability and age at onset (Chelban et al., 2024). For a phenotypic description and a discussion of genetic heterogeneity of IBGC, see IBGC1 (213600).