[Neonatal onset of Menkes disease: diagnosis interest of cupremia and microscopic examination of the hairs]

Peptidylgycine α-amidating monooxygenase and copper: a gene-nutrient interaction critical to nervous system function

Peptidylgycine alpha-amidating monooxygenase (PAM), a highly conserved copper-dependent enzyme, is essential for the synthesis of all amidated neuropeptides. Biophysical studies revealed that the binding of copper to PAM affects its structure, and cell biological studies demonstrated that the endocytic trafficking of PAM was sensitive to copper. We review data indicating that genetic reduction of PAM expression and mild copper deficiency in mice cause similar alterations in several physiological functions known to be regulated by neuropeptides: thermal regulation, seizure sensitivity, and anxiety-like behavior.

Interactions of peptide amidation and copper: novel biomarkers and mechanisms of neural dysfunction

Mammalian genomes encode only a small number of cuproenzymes. The many genes involved in coordinating copper uptake, distribution, storage and efflux make gene/nutrient interactions especially important for these cuproenzymes. Copper deficiency and copper excess both disrupt neural function. Using mice heterozygous for peptidylglycine alpha-amidating monooxygenase (PAM), a cuproenzyme essential for the synthesis of many neuropeptides, we identified alterations in anxiety-like behavior, thermoregulation and seizure sensitivity. Dietary copper supplementation reversed a subset of these deficits. Wildtype mice maintained on a marginally copper-deficient diet exhibited some of the same deficits observed in PAM(+/-) mice and displayed alterations in PAM metabolism. Altered copper homeostasis in PAM(+/-) mice suggested a role for PAM in the cell type specific regulation of copper metabolism. Physiological functions sensitive to genetic limitations of PAM that are reversed by supplemental copper and mimicked by copper deficiency may serve as indicators of marginal copper deficiency.

[From gene to disease: copper-transporting P ATPases alteration]

Copper is a trace metal, essential for many biological processes. Copper is also toxic if in excessive amounts; its homeostatic balance requires a delicate regulation. Several severe hereditary human disorders of copper regulatory mechanisms have been identified; they are related to mutations in gene ATP7A and ATP7B coding for copper-transporting proteins. Those mutations result in copper deficiency for ATP7A (Menkes disease) and copper overload for ATP7B (Wilson disease). Usually, clinical and biochemical phenotypes of these diseases are disparate. This article focuses on the molecular pathogenesis of Wilson and Menkes disease, and discusses how causing mutations are correlated with molecular defects and disease phenotypes.