Doctors discovered that an 11-month-old boy’s serious seizures and developmental problems were caused by his mother’s severe vitamin B12 deficiency. The mother had a condition called pernicious anemia that prevented her body from absorbing B12 properly. Even though the baby’s own B12 levels appeared normal in initial tests, he inherited the effects of his mother’s deficiency through breastfeeding. When the mother received B12 treatment, the baby’s seizures stopped and his development improved dramatically. This case shows how a parent’s nutritional deficiency can directly affect a baby’s brain health and development.

The Quick Take

  • What they studied: Why an 11-month-old baby had seizures, wasn’t growing properly, and was losing developmental skills he had already learned
  • Who participated: One baby boy and his mother; the baby was 11 months old when symptoms started at 5 months of age
  • Key finding: The baby’s mother had untreated pernicious anemia (a B12 deficiency condition), and treating the mother’s B12 deficiency completely resolved the baby’s seizures and developmental problems
  • What it means for you: Breastfeeding mothers with vitamin B12 deficiency may pass this problem to their babies, even if the mother’s symptoms seem mild. If a breastfed baby has unexplained seizures or developmental delays, checking the mother’s B12 levels may be important. This is especially relevant for mothers following strict vegan diets or those with digestive conditions affecting nutrient absorption.

The Research Details

This is a case report, which means doctors documented the medical story of one patient in detail. The baby came to the hospital with serious symptoms including seizures that were getting worse, failure to gain weight, and loss of skills he had already developed. Doctors performed many tests including brain imaging, genetic testing, and blood work to try to find the cause. The breakthrough came when doctors tested the mother’s vitamin B12 level and discovered it was dangerously low. The mother was then diagnosed with pernicious anemia, a condition where the body cannot absorb B12 from food because it lacks a special protein needed for absorption.

Case reports are important because they describe unusual or unexpected medical situations that might not show up in larger studies. This case is valuable because it shows a connection between maternal B12 deficiency and serious neurological problems in a breastfed baby. It highlights that doctors should consider checking parents’ nutritional status when babies have unexplained neurological symptoms, not just the baby’s own nutrient levels.

This is a single case report, so it describes one patient’s experience rather than comparing many patients. While case reports cannot prove that something causes a disease, this case is compelling because the baby improved dramatically when the mother was treated. The doctors performed thorough testing and ruled out genetic causes, making the nutritional explanation more convincing. However, because it’s only one case, we cannot be certain this would happen the same way in other families.

What the Results Show

The 11-month-old boy presented with a combination of serious symptoms: he had started having seizures around 5 months of age that were getting progressively worse, he wasn’t gaining weight properly, he was losing skills he had already learned (developmental regression), and he refused to eat solid foods. Blood tests showed very high levels of certain compounds (propionylcarnitine, homocysteine, and methylmalonic acid) that indicate problems with how the body processes B12. Brain imaging showed his corpus callosum (a structure connecting the two sides of the brain) was thinner than normal. Genetic testing came back normal, ruling out inherited metabolic disorders. The key discovery was that the baby’s mother had completely undetectable B12 levels and was diagnosed with pernicious anemia. When the mother started receiving B12 injections, the baby’s blood test abnormalities completely normalized, his seizures stopped, and his development improved significantly.

The baby also had other symptoms related to B12 deficiency including mouth sores, low white blood cell counts, and anemia (low red blood cells). These additional symptoms all improved along with the neurological symptoms once the mother received treatment. The case demonstrates that B12 deficiency can affect multiple body systems, not just the nervous system. The baby’s aversion to solid foods also resolved as his condition improved.

B12 deficiency is known to cause neurological problems in babies, but most cases are identified through the baby’s own B12 levels. This case is unusual because the baby’s measured B12 level appeared normal, yet he still had severe B12 deficiency symptoms. This suggests that standard B12 blood tests might not always catch B12 deficiency in breastfed babies whose mothers are deficient. Previous research has shown that breastfed babies depend on their mother’s B12 status, but this case provides a dramatic example of how serious the consequences can be when maternal deficiency goes undetected.

This is a single case report, so we cannot know how common this situation is or whether it would happen the same way in other families. The case does not prove that maternal B12 deficiency causes infant seizures in all cases, only that it did in this particular situation. We don’t have information about how long the baby had been breastfeeding or whether he received any formula. The case also doesn’t tell us whether the baby might have had some genetic predisposition that made him more vulnerable to his mother’s deficiency.

The Bottom Line

Breastfeeding mothers should ensure adequate B12 intake through diet, supplements, or injections, particularly those following vegan diets or with digestive conditions. Healthcare providers should consider checking maternal B12 levels when breastfed babies present with unexplained seizures, developmental delays, or failure to thrive. Babies showing these symptoms should have comprehensive metabolic testing, not just standard B12 blood tests. (Confidence level: Moderate - based on one compelling case, but not yet confirmed in larger studies)

Breastfeeding mothers, particularly those who are vegan or vegetarian, those with digestive disorders, or those with a family history of pernicious anemia. Parents of babies with unexplained seizures or developmental problems. Healthcare providers caring for infants with neurological symptoms. This case is less relevant for formula-feeding families, as formula is fortified with B12.

In this case, the baby showed improvement in seizures within weeks of the mother starting B12 treatment, with complete resolution over several months. However, recovery timelines may vary depending on how long the deficiency lasted and how severe the brain effects were.

Want to Apply This Research?

  • For breastfeeding mothers: Track B12 intake sources daily (animal products, fortified foods, or supplements) and note any symptoms like fatigue, numbness, or mood changes. For parents of infants: Track seizure frequency, developmental milestones achieved, and feeding behaviors weekly to monitor for improvements or concerns.
  • Breastfeeding mothers should add a B12 tracking feature to ensure daily adequate intake through food or supplements. Parents concerned about infant development should use the app to document symptoms and share detailed records with their pediatrician, including family dietary patterns and any maternal health conditions.
  • Mothers should set reminders for B12 supplementation if needed and track energy levels and neurological symptoms monthly. Parents of affected infants should maintain a detailed symptom log including seizure frequency, developmental progress, and feeding patterns to share with healthcare providers during follow-up appointments.

This case report describes one patient’s experience and should not be used for self-diagnosis. If your baby is experiencing seizures, developmental delays, or failure to thrive, seek immediate medical evaluation from a pediatrician or pediatric neurologist. If you are a breastfeeding mother with concerns about your B12 status, consult with your healthcare provider about appropriate testing and supplementation. This information is educational and does not replace professional medical advice, diagnosis, or treatment.