Déficit de piruvato deshidrogenasa asociado a la mutación C515T en el exón 6 del gen E1

Abstract

Pyruvate dehydrogenase (PDH) deficiency constitutes the most frequent metabolic origin of congenital lactic acidosis and is also responsible for a less usual form, found exclusively in females, which leads to a dysmorphic syndrome accompanied by severe cerebral malformations. The most common defect affects fraction E1alpha (gene Xp22.1-22.2).To report the case of a young female with PDH deficiency, dysmorphic syndrome, cerebral deformations and an unidentified mutation in the corresponding gene.An 8-month-old female with microcephaly, a narrow forehead, nasal hypoplasia, anteverted nostrils, thin lips, axial hypotonia, epileptic seizures and an umbilical hernia. Magnetic resonance imaging of the brain revealed intense supra- and infratentorial cortico-subcortical atrophy, ventricular dilatation and agenesis of the corpus callosum. Lactic and pyruvic acid concentrations were high both in blood and in cerebrospinal fluid (CSF), and the level of alanine was high in CSF. Muscular histology results were normal. PDH complex activity in fibroblasts and in muscle tissue, as well as that of the mitochondrial respiratory chain complexes in muscle homogenate, were found to be normal. A molecular genetic study of the gene for PDHE1alpha, both in formed elements in the blood and in fibroblasts, showed a C > T change in nucleotide 515 (C515T) of exon 6, which causes a P172L change in the protein. A study of 108 controls ruled out the possibility of a polymorphism. The parents did not have the mutation.The C515T mutation of exon 6 of the gene for PDH E1alpha is described. Normal activity of the PDH complex in fibroblasts and in muscle tissue does not exclude this condition.