Question

Which of the following correctly represents the chain of causation from gene defect to disease phenotype?

Options

• Disrupted metabolic/structural function → Gene mutation → Abnormal or absent protein → Disease phenotype

• Gene mutation / chromosomal error → Abnormal or absent protein → Disrupted metabolic/structural function → Disease phenotype

• Abnormal or absent protein → Gene mutation → Disrupted metabolic/structural function → Disease phenotype

• Disease phenotype → Disrupted metabolic/structural function → Abnormal or absent protein → Gene mutation

Answer 1

The molecular basis of genetic disorders follows a specific sequence: a gene mutation or chromosomal error first occurs, which leads to production of abnormal or completely absent proteins. These defective proteins then disrupt normal metabolic or structural functions, ultimately resulting in the observable disease phenotype.