Overview
Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A (also called MoCD type A) is a very rare and serious inherited metabolic disorder. In this condition, the body cannot properly make a small but essential molecule called molybdenum cofactor. This cofactor is needed for several important enzymes to work, including sulfite oxidase, which breaks down sulfur-containing amino acids from the proteins we eat. When sulfite oxidase does not work, toxic sulfite builds up in the body, especially in the brain, causing severe damage. Babies with MoCD type A typically appear normal at birth but within the first days to weeks of life develop serious neurological problems. These include difficult-to-control seizures, feeding difficulties, abnormal muscle tone, and progressive brain damage. Brain imaging often shows widespread injury and brain tissue loss. The condition also leads to a characteristic lens dislocation in the eyes over time. Historically, there has been no effective treatment and the prognosis has been very poor, with most affected children experiencing profound intellectual disability and shortened lifespan. However, a groundbreaking treatment called fosdenopterin (brand name Nulibek) was approved by the FDA in 2021 specifically for MoCD type A. This medication replaces the missing cofactor precursor and, when started very early in life, can significantly reduce brain damage and improve outcomes. Early diagnosis is therefore critically important.
Also known as:
Key symptoms:
Seizures that are hard to control, often starting in the first days of lifeFeeding difficulties in newbornsAbnormal muscle tone (either too stiff or too floppy)Progressive brain damageSevere intellectual disabilityLens dislocation in the eyesAbnormal movements or posturingFailure to reach developmental milestonesMicrocephaly (small head size developing over time)Breathing difficultiesIrritability and excessive cryingLoss of previously acquired skillsPoor growth and failure to thrive
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Neonatal
Begins at or shortly after birth (first 4 weeks)
Treatments
No FDA-approved treatments are currently listed for Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A.
View clinical trials →Clinical Trials
View all trials with filters →No actively recruiting trials found for Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A at this time.
New trials open frequently. Follow this disease to get notified.
Specialists
View all specialists →No specialists are currently listed for Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A.
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A.
Community
No community posts yet. Be the first to share your experience with Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A.
Start the conversation →Latest news about Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A
No recent news articles for Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A.
Follow this condition to be notified when news becomes available.
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.Is my child eligible for fosdenopterin (Nulibek) treatment, and how soon can it be started?,How much brain injury has already occurred based on the MRI, and what does this mean for my child's development?,What seizure medications are best for my child, and what side effects should I watch for?,Are there dietary changes we should make, and can we work with a metabolic dietitian?,How often will my child need eye exams to check for lens dislocation?,Is genetic counseling available for our family to understand the risk for future pregnancies?,Are there any clinical trials or new treatments being studied that my child might benefit from?
Common questions about Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A
What is Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A?
Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A (also called MoCD type A) is a very rare and serious inherited metabolic disorder. In this condition, the body cannot properly make a small but essential molecule called molybdenum cofactor. This cofactor is needed for several important enzymes to work, including sulfite oxidase, which breaks down sulfur-containing amino acids from the proteins we eat. When sulfite oxidase does not work, toxic sulfite builds up in the body, especially in the brain, causing severe damage. Babies with MoCD type A typically appear normal at
How is Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A inherited?
Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A typically begin?
Typical onset of Sulfite oxidase deficiency due to molybdenum cofactor deficiency type A is neonatal. Age of onset can vary across affected individuals.