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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
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Hydrops fetalis d/t Hb ba is associated with?
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The correct answer is  - Hydrops fetalis is seen in most severe form of a-thalassemia, caused by deletion of all four a-globin genes. - Hb in these fetus have tetramers of g-globin chains (hemoglobin Bas) which have high affinity for oxygen. - This results in decreased delivery of oxygen to the tissues. - Survival in early development of these fetus is d/t expression of z chains, an embryonic globin that pairs with g chains to form functional z 2 g 2 Hb tetramer.