MEDNIK syndrome

MEDNIK syndrome (Mental retardation, Enteropathy, Deafness, Neuropathy, Ichthyosis, and Keratodermia) is an extremely rare autosomal recessive multisystem disorder caused by mutations in the AP1S1 gene, which encodes the sigma 1A subunit of the adaptor protein complex 1 (AP-1). This protein complex plays a critical role in intracellular vesicle trafficking, and its disruption leads to abnormal copper metabolism resembling features seen in both Menkes disease and Wilson disease. The syndrome was first described in a French-Canadian population from the Kamouraska region of Quebec. The condition typically presents in the neonatal or early infantile period with a combination of congenital ichthyosis (scaly skin), sensorineural deafness, peripheral neuropathy, intellectual disability, and enteropathy (chronic diarrhea). Affected individuals may also exhibit cholestasis (impaired bile flow from the liver), elevated liver copper levels, and low serum ceruloplasmin and copper levels, reflecting the underlying copper metabolism disturbance. Palmoplantar keratoderma (thickened skin on palms and soles) is another characteristic feature. The neurological manifestations include psychomotor delay and progressive peripheral neuropathy. Treatment for MEDNIK syndrome is primarily supportive and symptomatic. Zinc acetate therapy has been used to manage the copper metabolism abnormalities, similar to approaches used in Wilson disease, and may help normalize copper and ceruloplasmin levels. Dermatological management with emollients and keratolytics addresses the ichthyosis. Hearing aids or cochlear implants may be considered for sensorineural hearing loss. Early intervention programs and developmental support are important for managing intellectual disability. No curative therapy currently exists, and long-term prognosis depends on the severity of organ involvement, particularly hepatic and neurological complications.

Common questions about MEDNIK syndrome