A hypotonic newborn or infant with pale skin and sparse, friable, hypopigmented, or depigmented hair should have his copper and ceruloplasmin plasma levels evaluated because this is the usual clinical presentation of Menkes disease. Menkes disease is an X-linked recessive disease caused by a defect in the ATP7A gene, identified in 95% to 98% of the cases. Identifying the mutation confirms the diagnosis and allows for prenatal counseling and diagnosis in a future pregnancy. When administered within the first few months of life, copper histidinate, given subcutaneously in a dose of 50 to 150 mg/kg per day, appears to be effective not only by increasing life expectancy from 3 to 13 years but also by improving neurologic symptoms and neurodevelopmental outcomes in approximately 30% of the patients.