Ans. (b) Zinc deficiencyRef. Harrison's 19th ed. / 96e-9* Zinc is an essential trace nutrient required for the proper function of more than 100 enzymes and plays a crucial role in nucleic acid metabolism.* Acrodermatitis enteropathica is an autosomal recessive disorder postulated to occur as a result of mutations in the SLC39A4 gene located on band 8q24.3.* This protein is highly expressed in the enterocytes in the duodenum and jejunum. Therefore, affected individuals have a decreased ability to absorb zinc from dietary sources. Absence of a binding ligand needed to transport zinc may further contribute to zinc malabsorption.* Clinical manifestations include diarrhea, alopecia, muscle wasting, depression, irritability, and a rash involving the extremities, face, and perineum. The rash is characterized by vesicular and pustular crusting with scaling and erythema.* Features of acrodermatitis enteropathica start appearing in the first few months of life, if mother discontinues breast milk.Deficiency and toxicity of several metalsPhosphorus ElementDeficiencyToxicityTolerable Upper (Dietary) Intake LevelBoronNo biologic function determinedDevelopmental defects, male sterility, testicular atrophy20mg/d (extrapolated from animal data)CalciumReduced bone mass, osteoporosisRenal insufficiency (milk-alkali syndrome) nephrolithiasis, impaired iron absorption, thiazide diuretics.2500 mg/d (milk alkali)CopperAnemia, growth retardation, defective keratinization and pigmentation of hair, hypothermia, degenerative changes in aortic elastin, osteopenia, mental deterioration.Nausea, vomiting, diarrhea, hepatic failure, tremor, mental deterioration, hemolytc anemia, renal dysfunction10 mg/d (liver toxicity)ChromiumImpaired glucose toleranceOccupational',Renal failure, dermatitis, pulmonary cancerNot determinedFluoride|Dental cariesDental and skeletal flurosis, osteosclerosis10 mg/d (Blurosis)IodineThyroid enlargement, |T4 cretinismThyroid dysfunction, acne-like eruptions.1100 mg/d (thyroid dysfunction)IronMuscle abnormalities, koilonychia, pica anemia, |work performance, impaired cognitive development, premature labor, |perinatal maternal deathGastrointestinal effects, (nausea, vomiting, diarrhea, constipation), iron overload with organ damage, acute and chronic systemic toxicity, increased susceptibility to malaria, increased risk association with certain chronic diseases (e.g. diabetes)45 mg/d of elemental Iron (gastrointestinal side effects)ManganeseImpaired growth and skeletal development reproduction, lipid and carbohydrate metabolism, upper body rashGeneral: Neurotoxicity, Parkinson-like symptoms Occupational: Encephalitis like syndrome, Parkinson like syndrome, psychosis, pneumoconiosis.11 mg/d (neurotoxicity)MolybdenumSevere neurologic abnormalitiesReproductive and fetal abnormalities2mg/d (extrapolated from animal data)SeleniumCardiomyopathy, heart failure, striated muscle degenerationGeneral: Alopecia , nausea, vomiting, abnormal nails, emotional400 pg/d (hair, nail changes)PhosphorusRickets (osteomalacia) proximal muscle weakness, rhabdomyolysis, paresthesia, ataxia, seizure confusion, heart failure, hemolysis acidosis.Hyperphosphatemia4000 mg/dZincGrowth retardation, |taste and smell alopecia, dermatitis, diarrhea, immune dysfunction, failure to thrive, gonasal atrophy, congenital malfomations.General: Reduced copper, absorption, gastritis, sweating fever,nausea, vomitingOccupational; Respiratory distress, pulmonary fibrosis40 mg/d (impaired copper metabolism)