Metabolic Consequences of Biotin Deficiency

The activities of biotin-dependent carboxylases fall in deficiency, resulting in impaired gluconeogenesis, with accumulation of lactate, pyruvate, and alanine, and impaired lipogenesis, with accumulation of acetyl CoA, resulting in ketosis. There are also changes in the fatty acid composition of membrane lipids. A variety of abnormal organic acids are excreted by both biotin-deficient patients and experimental animals (as shown in Table 11.1). 

There is accumulation of the apoenzymes of biotin-dependent carboxylases in deficiency. Response to repletion is rapid, as a result of activation of the apoenzymes activation of biotin-dependent apoenzymes in vitro may provide an index of status (Section 11.4). 

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