Compound Heterozygous MRPS14 Variants Associated With Leigh Syndrome.

MRPS14 is a gene that provides instructions for making a protein needed for how mitochondria (the “energy producers” in our cells) make other proteins. Problems with this gene can affect how cells produce energy. So far, only one person with a disorder linked to this gene (called COXPD38) had been described. In this report, we describe another child with two new changes in the MRPS14 gene (each inherited from a different parent). The child showed delays in movement and speech by age 2, along with higher-than-normal levels of certain substances in the blood that can indicate problems with energy production. Brain scans showed patterns typical of a condition called Leigh syndrome, a disorder that affects the nervous system. Another test confirmed a buildup of lactate, which is also a sign that the mitochondria aren’t working properly. Lab tests on the child’s cells showed reduced levels of the MRPS14 protein and another important mitochondrial protein (COX2). Altogether, these findings suggest that the genetic changes found in this child are likely the cause of their condition.