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Trifunctional Protein Deficiency (HADHB) Known Mutation Analysis

Long-chain-hydroxy Acyl-CoA dehydrogenase deficiency (LCHAD), and mitochondrial trifunctional protein deficiency (TFP) are disorders of long-chain fatty acid metabolism. They have overlapping clinical presentation that can include: feeding difficulties, lethargy, hypoglycemia, muscle weakness and liver dysfunction in infancy or early childhood. These symptoms are often triggered by prolonged fasting or viral infections. Muscle pain, breakdown of muscle tissue and peripheral neuropathy may occur later in childhood. These patients are at risk for complications such as life-threatening heart problems and sudden unexpected death. Carrier women pregnant with affected fetuses can develop Acute Fatty Liver of Pregnancy (AFLP).

The mitochondrial trifunctional protein consists of 3 enzymes that work together to metabolize long-chain fats. Most patients have isolated deficiency of the LCHAD enzyme caused by mutations in the HADHA gene. A small portion of patients have defects in all three enzymes, called TFP deficiency, which is due to mutations in the HADHA or HADHB gene.

Test Name: LCHAD/TFP (HADHB) Known Mutation Analysis
Test Code:
LCHADKNWN
Test Description:
Polymerase Chain Reaction (PCR) followed by sequence analysis of the HADHA gene for known mutations.
Synonyms:
MTP, mitochondrial trifunctional protein, long chain, LCHAD TFP
Indication:
This test is used for carrier testing at-risk relatives and prenatal testing for confirmed carriers. Mutations must be known.
Related Tests: Organic Acid Analysis, Urine  
For confirmation of newborn screening results, evaluating patients with episodes of lethargy or vomiting suggestive of a metabolic disorder and for follow-up of known patients for assessment of management.

Acylcarnitine Profile, Blood  
For confirmation of newborn screening results, evaluating patients with episodes of lethargy or vomiting suggestive of a metabolic disorder and for follow-up of known patients for assessment of management.

Maternal Cell Contamination - DNA  
Maternal DNA is compared to fetal DNA to evaluate whether maternal cell contamination of the fetal sample has occurred.

Clinical Links: Trifunctional Protein Deficiency OMIM Entry
Availability:
Mon - Fri
Turnaround Time:
1-2 weeks
Methodology:
PCR followed by Sequencing
Reference Range:
Interpretive report will be provided
Requisition:
Consent Form:
Sample Requirements: Type
Whole blood: 1-3 mL in EDTA (purple top) or ACD (yellow top).
DNA: 5 micrograms extracted DNA.
Prenatal samples: 2 T-25 flasks

Processing
Do not spin. Keep at room temperature

Shipping
Room temperature via overnight shipping. Blood samples must be processed within 3 days of collection
Samples Received:
Monday - Friday 8am - 5pm PST
Special Considerations:
For prenatal testing, mutations must be known and maternal cell contamination testing is required (ordered separately).
Cost:
Please e-mail Lab Client Services (labclientservices@seattlechildrens.org) or call at 206-987-2617 with any billing questions
CPT Code:
Please e-mail Lab Client Services (labclientservices@seattlechildrens.org) or call at 206-987-2617 with any billing questions