Related Experiment Video
Updated: Aug 4, 2026
05:26
Postconditioning with Lactate-enriched Blood for Cardioprotection in ST-segment Elevation Myocardial Infarction
Published on: May 28, 2019
MERRF syndrome with overwhelming lactic acidosis
1Department of Pediatrics, USC + Los Angeles County Medical Center, USA.
Pediatric Neurology
|January 1, 1996
Summary
A rare mitochondrial DNA mutation causing Myoclonic epilepsy with ragged-red fiber syndrome (MERRF) can lead to a severe, rapidly progressing disease. This case highlights aggressive MERRF in a child, contrasting with typical adult presentations.
Area of Science:
- Genetics
- Neurology
- Mitochondrial Diseases
Background:
- Myoclonic epilepsy with ragged-red fiber syndrome (MERRF) is typically linked to a mitochondrial DNA mutation (8344 A>G) in the tRNA(Lys) gene.
- Previously reported adult MERRF patients with this mutation exhibit slow progression and mild to moderate symptoms.
- The clinical spectrum and progression rate of MERRF syndrome can vary significantly.
Observation:
- This study details an atypical MERRF case in a pediatric patient with a rapid and severe clinical course.
- Symptom onset occurred at age 7, with death by age 14 due to overwhelming lactic acidosis.
Findings:
- Postmortem tissue analysis revealed high percentages of mutant mitochondrial genomes across multiple organ systems.
- Genetic testing in 21 family members showed varying levels of the mutation in leukocytes.
Implications:
- This case underscores the potential for extreme phenotypic variability in MERRF, even with the common m.8344A>G mutation.
- Understanding the factors influencing MERRF severity and progression is crucial for patient management and genetic counseling.
More Related Videos
06:18Measurement of Myocardial Lactate Production for Diagnosis of Coronary Microvascular Spasm
Published on: September 17, 2021
08:56Modeling Mitochondrial Disease Using Brain Organoids: A Focus on Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like Episodes
Published on: October 10, 2025
Related Concept Videos
01:22Lysosomal Hydrolases
Lysosomes are the site for the degradation of macromolecules and biological polymers released during membrane trafficking events such as secretory, endocytic, autophagic, and phagocytic pathways. The membrane-enclosed area of the lysosome, called the lumen, contains hydrolytic enzymes active in an acidic environment. These acid hydrolases are functional at a pH between 4.5 and 5 and are involved in cellular processes such as cell signaling, energy metabolism, restoration of the plasma membrane,...
01:24Muscle Recovery and Fatigue
Muscle fatigue refers to the decline in a muscle's ability to maintain the force of contraction after prolonged activity. It primarily stems from changes within muscle fibers. Even before experiencing muscle fatigue, one may feel tired and have the urge to stop the activity. This response, known as central fatigue, occurs due to changes in the central nervous system, namely the brain and spinal cord. While there is no single mechanism that induces fatigue, it may serve as a protective response...
01:20Inborn Errors of Metabolism
Phenylketonuria (PKU) is a protein metabolism disorder characterized by high blood levels of the amino acid phenylalanine. This results from a mutation in the gene responsible for phenylalanine hydroxylase, an enzyme that converts phenylalanine into tyrosine. When this enzyme is deficient, phenylalanine builds up in the blood, leading to symptoms such as vomiting, rashes, seizures, growth deficiency, and severe mental retardation. An early diagnosis and a diet restricting phenylalanine intake...
01:23Microbial Fermentation
Fermentation is a crucial anaerobic metabolic process that enables microbes to derive energy from sugar without relying on oxygen or an electron transport chain. This process is fundamental to various biological and industrial applications and is classified based on the metabolic products generated.Role of Pyruvate in FermentationPyruvate and its derivatives serve as key electron acceptors in fermentative pathways. The oxidation of NADH to regenerate NAD+ is essential for the continuation of...
01:25Diabetic Ketoacidosis l: Introduction
DefinitionDiabetic ketoacidosis (DKA) is an acute, life-threatening complication of diabetes mellitus, characterized by a triad of hyperglycemia (blood glucose >250 mg/dL), ketonemia or ketonuria, and metabolic acidosis (arterial pH <7.30 and serum bicarbonate <18 mEq/L). It results from insulin deficiency combined with elevated levels of counterregulatory hormones—glucagon, catecholamines, cortisol, and growth hormone—leading to increased lipolysis, hepatic ketone production, and...
01:22Diabetic Ketoacidosis ll: Pathophysiology
Diabetic ketoacidosis (DKA) is a metabolic emergency characterized by hyperglycemia, ketonemia, and metabolic acidosis. It results from severe insulin deficiency and an excess of counterregulatory hormones, leading to uncontrolled lipolysis, ketogenesis, and widespread electrolyte and fluid disturbances.Pathophysiology The central event in DKA is a profound loss of insulin action. Without insulin, glucose uptake in insulin-dependent tissues is impaired, while hepatic glucose production...