This entry includes proteins involved in intracellular zinc homeostasis. A mutation in the human gene leads toan autosomal recessive cerebro-renal syndrome associated with early-onset neurological deterioration, severe intellectual disability, profound ataxia, camptocormia and oculomotor apraxia []. An uncharacterized homologue from Arabidopsis thaliana is known as metal tolerance protein C4 (MTPC4).