Symptoms and Warning Signs of Imerslund-Gräsbeck Syndrome

In the early stages, Imerslund-Gräsbeck Syndrome (IGS) can be difficult to spot because its symptoms often develop slowly and can mimic other common childhood conditions. Because IGS is a “selective” malabsorption disorder, your child may appear healthy and have a normal diet, yet their body is quietly running out of cobalamin (Vitamin B12) ^[1][2].

Most symptoms you will observe in IGS arise from the lack of Vitamin B12, which the body needs to build healthy blood cells and maintain the nervous system ^[3][4]. The loss of protein in the urine (proteinuria) is generally a laboratory finding rather than a cause of fatigue or pallor.

Common Daily Symptoms

You may notice a cluster of symptoms primarily driven by the B12 deficiency:

• Lethargy and Fatigue: Your child may seem unusually tired, nap more than usual, or lack the energy to play ^[5][4].
• Pale Skin (Pallor): Due to anemia, your child’s skin, lips, or nail beds may look remarkably pale ^[1].
• Poor Weight Gain: Your child might struggle to gain weight or grow at the expected rate ^[6][4].
• Poor Appetite and Mouth Sores: Some children lose interest in eating or develop painful aphthous stomatitis (mouth ulcers) ^[5][7].
• Infections: Severe B12 deficiency can cause low white blood cell counts, which might lead to recurrent infections, although ordinary childhood colds are nonspecific and not exclusive to IGS ^[8][5].

Neurological Signs and Progression

Vitamin B12 is essential for the myelin sheath, the protective coating that helps nerves send signals. If IGS is left untreated, the shortage of B12 can lead to a decline in brain and nerve function ^[9].

• Loss of Milestones: A child who was previously walking or crawling may suddenly seem “clumsy” or stop performing these motor skills entirely ^[9].
• Ataxia: This is a lack of muscle coordination. It can look like wobbling while standing, a shaky gait, or difficulty with balance ^[2].
• Developmental Delay: You might notice a slowing or regression in speech, social interaction, or cognitive tasks ^[10].

When to Contact the Specialist Soon

Contact your care team promptly—do not wait for your next appointment—if you notice:

• New or worsening weakness or clumsiness
• New swelling (edema) in the face, hands, or legs
• Blood in the urine or a major reduction in how much your child urinates
• Persistent vomiting
• A missed B12 dose

When to Seek Emergency Care

While most IGS symptoms develop over weeks or months, some situations require immediate medical evaluation at an emergency department. Do not wait for a lab test to confirm these symptoms.

Seek emergency care if your child experiences:

• Severe Anemia Symptoms: Fainting, severe breathing difficulty, chest symptoms, marked weakness, or a very fast resting heartbeat ^[1][5].
• Sudden Neurologic Decline: Any rapid loss of the ability to walk, stand, or move limbs, or the sudden onset of a stumbling walk ^[9][2].
• Pancytopenia or Bleeding: Unexplained bruising, tiny red spots on the skin (petechiae), or bleeding from the gums or nose that won’t stop ^[11][1].
• Pseudo-TMA: Severe IGS can mimic a life-threatening blood emergency called Thrombotic Thrombocytopenic Purpura (TTP), presenting with severe anemia, low platelets, and jaundice (yellowing of eyes/skin). This is a medical emergency. TTP requires urgent evaluation and potentially lifesaving treatments like plasma exchange while doctors work to confirm if the cause is B12 deficiency ^[12][13]. Do not delay emergency treatments while waiting for specialists to confirm pseudo-TMA.