Disorder Dietary Influence: Phenylketonuria

Phenylketonuria (PKU) is a rare inherited metabolic disorder. It affects how the body breaks down an amino acid called phenylalanine, found in many foods.

Why Diet Influences PKU

• Metabolic Pathway: In individuals with PKU, a specific enzyme (phenylalanine hydroxylase) is deficient or absent, preventing the conversion of phenylalanine into tyrosine.
• Build-up: This leads to a build-up of phenylalanine in the blood and tissues. High levels can damage the brain and nervous system, causing intellectual disability and other issues.
• Dietary Management: Strict adherence to a special low-phenylalanine diet from infancy is crucial. This diet restricts high-protein foods (like meat, dairy, nuts, and certain artificial sweeteners) and is carefully managed throughout life.
• Outcome: Proper dietary management significantly reduces the risk of severe health complications associated with PKU.

Other Mendelian Disorders

The other options are Mendelian disorders but are not primarily influenced or managed by diet in the same direct way as PKU:

• Cystic Fibrosis: Primarily affects lungs and digestive system; managed with medications and therapies.
• Haemophilia: A blood clotting disorder; managed with clotting factor replacement.
• Thalassemia: A blood disorder affecting haemoglobin; managed with blood transfusions and other medical treatments.

Therefore, Phenylketonuria is the Mendelian disorder influenced by diet.