IDEDNIK syndrome: a newly recognized rare genetic disorder caused by AP1S1 and AP1B1 mutations

IDEDNIK syndrome (formerly MEDNIK syndrome, OMIM #609313) is a rare autosomal recessive neurocutaneous disorder characterized by dysregulated copper metabolism and multisystem involvement. The primary causative gene, AP1S1, encodes the σ1A subunit of the adaptor protein complex AP-1, while mutations in AP1B1, encoding the β1 subunit, can cause a similar phenotype. Pathogenic mutations impair intracellular vesicle trafficking, disrupting the precise sorting and transport of multiple proteins, inc