This Woman is the First Ever Patient to Have Both aHUS and Cobalamin C Deficiency

When the 19-year-old French woman first visited the hospital, she was extremely lethargic. She displayed neurological symptoms. Upon kidney failure, the patient was admitted into the ICU. But soon, doctors realized that the patient was extremely unique. In fact, she is the first ever patient (patient zero) to be diagnosed with both aHUS and adult-onset Cobalamin C deficiency. Learn more about her unique diagnosis in the researchers’ case study, published in BMC Nephrology.


Atypical hemolytic uremic syndrome (aHUS) is a disorder which impacts kidney function. Genetic mutations result in aHUS. Overall, around 2 people (per every million) in the U.S. have aHUS.

Symptoms include:

  • Fatigue
  • Nausea and vomiting
  • Low blood platelet count
  • Lethargy
  • Confusion
  • Shortness of breath
  • High blood pressure
  • Blood in the urine
  • Anemia

In more severe cases, it can lead to kidney failure. Learn more about aHUS.

Cobalamin C Deficiency

Cobalamin C deficiency is known by many names: Cobalamin C disease, methylmalonic aciduria with homocystinuria. This inherited disease is caused by MMACHC gene mutations. This causes protein defects. As a result, vitamin B12 cannot break down amino acids and fats. When these accumulate, organ and tissue damage occurs.

Cobalamin C deficiency onset differs based on patient, but is usually diagnosed in infancy or early childhood. For this reason, the patient in the case study was unique in the disease’s adult onset status. Symptoms of Cobalamin C deficiency include:

  • Lethargy
  • Low muscle tone
  • Poor growth
  • Skin rashes
  • Involuntary muscle contractions
  • Microcephaly and hydrocephalus
  • Megaloblastic anemia
  • Stroke
  • Depression or anxiety
  • Impaired coordination
  • Developmental delays
  • Seizures
  • Psychosis
  • Heart and kidney issues

While there is no cure for Cobalamin C deficiency, treatments can reduce symptoms. Learn more about Cobalamin C deficiency.

Patient Study

After the patient was admitted to the ICU, doctors began running diagnostic tests. Thus, they discovered:

  • High levels of creatinine and homocysteine in the blood.
  • Abnormalities in the glomerular basement membrane, which sits between the kidney’s filtration barrier.

With these findings, doctors made a preliminary diagnosis of Cobalamin C deficiency. At the same time, the patient had:

circulating anti factor H antibody.

Basically, these antibodies were enough to make a simultaneous diagnosis of aHUS. The combination has never before been described or reported. The treatment included:

  • Vitamin B12
  • Betain
  • Folic acid
  • Rituximab
  • Eculizumab

Six months later, the patient’s condition drastically improved. Her bloodwork was negative for anti-factor H antibodies, and showed no signs of red blood cell destruction or low levels of red blood cells.

Find the source article here.

Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

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