BPAN is considered an ultra-rare disorder with an estimated prevalence of about 2-3 / million. Individuals with BPAN have developmental delay and intellectual disability, significantly impaired expressive language, early-onset seizures of varying types, and motor dysfunction. After remaining stable during childhood and often early adulthood, a period of regression with parkinsonism and progressive cognitive decline is common. In most cases, de novo pathogenic variants in the WDR45 gene cause BPAN, which is an x-linked dominant condition. Rarely, it is inherited from a parent with somatic or gonadal mosaicism. Since most pathogenic variants are de novo, the recurrence risk in the siblings of isolated probands is low. Treatment is symptomatic and varies based on age and stage of disease.
WDR45