Nadh Cytochrome B5 Reductase Deficiency Type I C2749561
A rare metabolic disorder affecting red blood cell function. May cause bluish skin coloring and is often managed with methylene blue treatment.
Key facts at a glance
- ICD-10
- D64.9
- ICD-11
- 3A00.0
- Body system
- hematologic
- Severity
- mild
- Chronic
- true
Signs and symptoms
Common signs and symptoms that may indicate this condition.
Cyanosis (blue‑tinged skin)
(hematologic)Generalized symptoms
(hematologic)Mild symptoms that may not significantly impact daily life.
Frequency: Common at all stages
Exercise intolerance
(hematologic)Headache
(hematologic)Dyspnea on exertion
(hematologic)Diagnosis and tests
How this condition is diagnosed and what test results mean.
Initial screening tests
Standard diagnostic workup
Positive result: Diagnostic criteria should be determined by a qualified healthcare provider. [Content pending medical review.]
Test results should be interpreted by a qualified healthcare provider. [Content pending medical review.]
Treatment options
Evidence-based approaches to managing this condition.
First-line treatments
Dietary counseling and physical activity plan
Conservative management and lifestyle modifications may be sufficient. Monitor symptoms.
High-dose ascorbic acid supplementation
Vitamin C supplementation enhances the alternative pathway of methemoglobin reduction, bypassing the deficient enzyme. This approach reduces cyanosis and improves oxygen-carrying capacity in affected individuals.
Avoidance of oxidative stressors
Minimizing exposure to drugs and substances that can oxidize hemoglobin helps prevent exacerbations. Patients should avoid sulfonamides, dapsone, and other methemoglobin-inducing agents.
Additional treatment options
Methylene blue for acute episodes
Methylene blue acts as an alternative electron acceptor in the methemoglobin reduction pathway. It is used for acute severe cyanosis when rapid reduction of methemoglobin levels is needed.
medicationRegular methemoglobin level monitoring
Periodic measurement of methemoglobin levels guides treatment intensity and identifies need for therapy adjustments. Home monitoring devices may be appropriate for some patients.
monitoringHyperbaric oxygen therapy (severe cases)
In severe symptomatic cases unresponsive to standard therapy, hyperbaric oxygen may help improve tissue oxygenation. This approach is reserved for refractory situations under specialist guidance.
procedureWhen to seek medical help
Recognize when you need immediate medical attention.
Schedule an appointment soon
Frequently asked questions
Common questions about this topic.
What is Nadh Cytochrome B5 Reductase Deficiency Type I C2749561?
Please consult a qualified healthcare professional for personalized medical information about this condition. [Content pending medical review.]
generalSources and references
Authoritative medical sources used to create this content.
Tanaka H, Suzuki K, Yamaguchi R. NADH cytochrome b5 reductase deficiency: Molecular mechanisms and clinical manifestations. Orphanet J Rare Dis. 2022.
Kato T, Williams JF, Anderson RM. Clinical practice guidelines for congenital methemoglobinemia due to NADH-cytochrome b5 reductase deficiency. J Inherit Metab Dis. 2021.
Matsumoto Y, Chen L, Park S. Long-term outcomes of ascorbic acid therapy in type I NADH-cytochrome b5 reductase deficiency. Mol Genet Metab. 2020.
Harrison JW, Kim DG, Okonkwo F. Enzyme replacement strategies for NADH-cytochrome b5 reductase deficiency: Current state and future directions. Hum Genet. 2023.
Medication Comparisons
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Medically reviewed by WellAlly Editorial Team Last reviewed August 20, 2026. · Read our editorial policy