Summary about Disease
Long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHAD deficiency) is an inherited metabolic disorder that prevents the body from effectively breaking down certain fats called long-chain fatty acids. This breakdown is crucial for energy production, particularly during periods of fasting or illness. When LCHAD is deficient, these fats can accumulate to toxic levels, causing serious health problems.
Symptoms
Symptoms can vary in severity and may include:
Hypoglycemia (low blood sugar), especially during fasting or illness
Lethargy and fatigue
Poor feeding in infants
Muscle weakness (hypotonia)
Liver problems (hepatomegaly)
Heart problems (cardiomyopathy, arrhythmias)
Peripheral neuropathy (nerve damage in the extremities)
Rhabdomyolysis (muscle breakdown)
Seizures
Coma
Sudden infant death syndrome (SIDS) in severe cases
Causes
LCHAD deficiency is caused by mutations in the HADHA gene, which provides instructions for making part of the long-chain 3-hydroxyacyl-CoA dehydrogenase enzyme. This enzyme complex is essential for the mitochondrial beta-oxidation pathway, which breaks down long-chain fatty acids. The deficiency is inherited in an autosomal recessive pattern, meaning an individual must inherit two copies of the mutated gene (one from each parent) to be affected.
Medicine Used
There is no specific medicine to "cure" LCHAD deficiency. Management focuses on preventing symptoms through dietary modifications and, in some cases, supplements:
Dietary Management: A low-fat, high-carbohydrate diet with frequent meals and snacks to avoid fasting is crucial. Medium-chain triglyceride (MCT) oil may be used as a supplemental energy source, as it doesn't require the LCHAD enzyme for metabolism.
Carnitine Supplementation: Carnitine may be prescribed to help remove accumulated fatty acids from cells.
Glucose Administration: Intravenous glucose may be necessary during acute episodes of illness or hypoglycemia.
Is Communicable
No, LCHAD deficiency is not communicable. It is a genetic disorder, not an infectious disease.
Precautions
Precautions focus on preventing metabolic crises:
Strict Dietary Adherence: Following the prescribed low-fat, high-carbohydrate diet is paramount.
Avoid Prolonged Fasting: Frequent meals and snacks, especially before bedtime, are essential.
Prompt Medical Attention for Illness: During illness, the body's energy needs increase, and the risk of metabolic crisis rises. Immediate medical evaluation is necessary for fever, vomiting, diarrhea, or decreased appetite. Emergency protocols involving glucose administration should be established with the medical team.
Emergency Protocol: A written emergency protocol for parents and caregivers detailing when and how to administer glucose, and who to contact, is very important.
Monitoring: Regular monitoring of blood glucose levels and liver function is necessary.
How long does an outbreak last?
LCHAD deficiency is a chronic condition, not an acute outbreak. However, metabolic crises can occur intermittently, particularly during illness or fasting. The duration of a crisis depends on the severity and promptness of treatment. With appropriate intervention, a crisis can be resolved within hours to days.
How is it diagnosed?
Diagnosis typically involves:
Newborn Screening: Many states include LCHAD deficiency in their newborn screening programs, using a blood spot test to detect abnormal acylcarnitine levels.
Acylcarnitine Profile: A blood test that measures the levels of different acylcarnitines, which can indicate a fatty acid oxidation disorder.
Urine Organic Acid Analysis: Detects abnormal organic acids in the urine that can result from metabolic defects.
Fibroblast Enzyme Assay: Measures the activity of the LCHAD enzyme in cultured skin cells (fibroblasts).
Genetic Testing: Confirms the diagnosis by identifying mutations in the HADHA gene.
Timeline of Symptoms
The onset and timeline of symptoms vary depending on the severity of the deficiency:
Newborn Period: Some infants are identified through newborn screening and may be asymptomatic initially with proper dietary management. However, symptoms such as poor feeding, lethargy, or hypoglycemia can appear soon after birth if not managed appropriately.
Infancy: Symptoms like muscle weakness, liver problems, and heart problems may develop within the first few months or years of life.
Childhood: Episodes of rhabdomyolysis, peripheral neuropathy, and heart problems can occur throughout childhood, particularly during illness or prolonged fasting.
Adulthood: While less common, some individuals with milder forms may not be diagnosed until adulthood, presenting with symptoms like muscle pain, fatigue, or neuropathy.
Important Considerations
Early Diagnosis and Management: Early diagnosis through newborn screening and prompt initiation of dietary management are crucial for improving outcomes.
Lifelong Management: LCHAD deficiency requires lifelong dietary management and close medical follow-up.
Genetic Counseling: Genetic counseling is recommended for families with a child diagnosed with LCHAD deficiency to understand the inheritance pattern and recurrence risk.
Multidisciplinary Care: Management should involve a multidisciplinary team, including a metabolic specialist, dietician, cardiologist, neurologist, and other healthcare professionals as needed.
Education and Support: Families need comprehensive education about the condition, its management, and potential complications. Support groups can provide valuable emotional and practical assistance.