This statement is true. The I and i antigens are carbohydrates present on glycolipids and glycoproteins. They are **developmentally regulated**. At birth, cord blood and infant red cells express the **i antigen** strongly (linear poly-N-acetyllactosamine chains). The **I antigen** is a branched structure formed from the i antigen by the action of the I-branching enzyme (GCNT2). Over the first 18-24 months of life, the I-branching enzyme becomes active, converting the linear i chains into branched I structures. By adulthood, red cells express strong **I antigen** and very weak i antigen. This is clinically relevant because **cold agglutinin disease** in adults is often caused by anti-I autoantibodies, while in infants, transient hemolysis can be caused by anti-i. The rare adult i phenotype (lack of I) is associated with congenital cataracts.

Break down complex topics into smaller, manageable chunks for easier recall.

Zambia

• Joseph Soko – 101 pts

• Visual Pathway Lesions
• Positive and Negative Symptoms
• Hallucinations and Delusions
• Antipsychotic Medications
• Emergency: Environmental Emergencies