A 5-year-old boy is brought to the outpatient clinic with a history of recurrent respiratory tract infections, chronic diarrhea, and failure to thriv…

Menkes disease (kinky hair disease) is an X-linked recessive disorder of copper metabolism caused by mutations in the ATP7A gene. This leads to defective intestinal copper absorption, resulting in systemic copper deficiency. Clinical features include sparse, steel-wire or twisted hair (pili torti), severe psychomotor retardation, hypotonia, failure to thrive, and neurodegeneration. Serum copper and ceruloplasmin levels are characteristically low, distinguishing it from Wilson disease where copper accumulates in tissues.