[2][3] People with MEDNIK syndrome often have a high forehead, upslanting palpebral fissures, a depressed nasal bridge, low-set ears, growth retardation, and brain atrophy apparent upon imaging.
Both ATPases, ATP7A (Menkes) and ATP7B (Wilson's) are located in the trans-Golgi network and are responsible for transporting copper to cuproenzymes synthesized within the secretory compartments.
[2] Patients with MEDNIK syndrome have been shown to display combined clinical and biochemical signs of both Menkes and Wilson's diseases.
The mutation that causes the MEDNIK syndrome occurs in the gene, AP1S1, which codes for the smallest subunit of the AP1 adaptor complex.
A mutation in AP1S1 causes abnormal intracellular copper trafficking which subsequently affects copper-dependent enzymes leading to the symptoms of MEDNIK disease.