You are examining a 1-year-old infant who is presenting with liver failure and suffers from frequent seizures. An analysis of mitochondrial function from a skeletal muscle biopsy shows a significant respiratory deficit. A molecular analysis shows that there is a deletion of the mtDNA encompassing the gene encoding DNA polymerase g. This patient is most likely suffering from which of the following diseases?
A) Alpers disease
B) Kearns-Sayre syndrome
C) Leigh syndrome
D) MELAS
E) myoclonic epilepsy and ragged red fiber disease (MERRF)

Question

Quizplus · Accepted Answer

Alpers disease is associated with mutations in the POLG gene, which encodes the mitochondrial DNA polymerase gamma, leading to liver failure, seizures, and mitochondrial dysfunction.  Alpers disease, which usually manifests in infancy, is associated with intractable seizures and a failure to meet meaningful developmental milestones. Primary symptoms of the disease are developmental delay, progressive mental retardation, hypotonia (low muscle tone), spasticity (stiffness of the limbs), and progressive dementia. The typical seizures are of a type that consists of repeated myoclonic (muscle) jerks. Experimental evidence indicates that Alpers disease is associated with deficiencies in the mtDNA-encoded DNA polymerase g.

You Are Examining a 1-Year-Old Infant Who Is Presenting with Liver