Isovaleric Acidemia Mutation Panel

Isovaleric acidemia is a disease that prevents the body from breaking down the amino acid leucine. The onset is typically in early infancy and includes symptoms of a distinctive odor, poor feeding, vomiting, seizures, lethargy, organic acidemia, organic aciduria, coma, and premature death. Later onset of the disease is associated with symptoms of failure to thrive and developmental delay. The condition can be managed with a strict diet. The incidence of isovaleric acidemia is estimated to be ~ 1 in 250,000.

Gene analysis for the various targeted mutations is performed by polymerase chain reaction and melting curve analysis to detect the mutant and wild-type forms of the gene. Sequence-specific oligonucleotide probes are labeled with fluorescent dyes, which hybridize to their complementary sequence target in PCR products. The fluorescence resonance energy transfer (FRET) from one fluorophore to another adjacent fluorophore is measurable and is directly proportional to the amount of target DNA generated during PCR. Allele-specific melting curves are generated by slow thermal denaturing of the probe: template hybrid. Melting curves are generated by monitoring fluorescence throughout denaturation, and melting peaks are generated by plotting the inverse derivative of fluorescence versus temperature (−dF/dT).