Clinical Case Study: Pyruvate Dehydrogenase Complex Deficiency (PDCD)
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Your patient is a male infant born apparently healthy, although with a somewhat low birth weight. The parents report that the child has developed several disturbing symptoms: he has poor muscle tone (hypotonia), seems very tired (lethargy), breaths rapidly (tachypnea), has abnormal eye movements and has suffered a few seizures. The baby has attended daycare since he was three months old, and his parents are concerned that he has contracted a microbial disease. Your order a series of tests. The child shows no signs of an infectious disease; however, one blood test indicates that he has high levels of lactic acid in his blood, a condition called lactic acidosis. He also has elevated levels of the amino acid alanine. Additional tests finally reveal that he is suffering from a genetic condition called pyruvate dehydrogenase complex deficiency (PDCD). PDCD is caused by a mutation in a gene called PDHA1; the mutation causes the PDC complex to malfunction and as a result, pyruvate is not converted to acetyl-CoA. You refer the family to a genetic counselor who informs the parents that PDCD cannot be cured but can be treated. The child will be given cofactors including carnitine, thiamine, and lipoic acid to stimulate PDC function. He will also be kept on a high-fat/ low-carbohydrate (ketogenic) diet and will be given medications to prevent the seizures. Unfortunately, the child's long-term prognosis is not very good: people with PDCD sometimes pass away early in life. Those that survive may experience additional problems such as intellectual disability.