1. Inborn errors of metabolism are rare genetic disorders that prevent the body from properly breaking down food into energy due to defects in metabolic enzymes.
2. There are three main metabolic genetic defects: phenylketonuria (PKU), galactosemia, and cystic fibrosis. PKU and galactosemia result from the inability to metabolize specific sugars or amino acids, while cystic fibrosis is caused by a defective gene that disrupts ion transport in epithelial cells.
3. The disorders cause abnormal accumulation of metabolites, damage to organs like the brain, liver, and lungs, and symptoms ranging from vomiting and diarrhea to chronic lung disease and malnutrition.