Pediatric Vitamin B12 Deficiency: When Autism Isn't Autism

Pharmacy TimesFebruary 2014 Autoimmune Disorders
Volume 80
Issue 2

Often misdiagnosed, vitamin B12 deficiency can place children at high risk for permanent brain injury.

Often misdiagnosed, vitamin B12 deficiency can place children at high risk for permanent brain injury.

Cobalamin (vitamin B12) deficiency is an easily treated disorder that often goes undiagnosed in infants and children, placing them at high risk for permanent brain injury. It is well documented that B12 deficiency can cause developmental delay, hypotonia, tremor, seizures, failure to thrive, reduced IQ, and mental retardation. Children with B12 deficiency exhibit speech, language, and social delays, behavioral issues, and problems with fine and gross motor movement. Magnetic resonance imaging (MRI) scans reveal brain atrophy, which commonly reverses after B12 therapy. However, if the deficiency is diagnosed late, permanent intellectual disability typically occurs even after treatment, and cognitive and language development remain seriously retarded.1

The signs and symptoms of pediatric B12 deficiency frequently mimic those of autism spectrum disorders. Both autistic and brain-injured B12- deficient children have obsessive-compulsive behaviors and difficulty with speech, language, writing, and comprehension. B12 deficiency can also cause aloofness and withdrawal. Sadly, very few children presenting with autistic symptoms receive adequate testing for B12 deficiency.

Infants and young children are often misdiagnosed. Irritability or gastric symptoms of B12 deficiency can be easily mistaken for colic or gastroenteritis. The apathetic or dull infant can be mistaken for an “easy” or “good” baby, and “late walkers” or “late talkers” can be considered variants of normal development. B12 deficiency can progress to failure to thrive and, if not promptly corrected, may lead to coma or death. Infants are also more vulnerable than adults to permanent brain injury because their central nervous systems are still developing.

When Mothers Have B12 Deficiency

In adults, symptoms of B12 deficiency often develop slowly over several months to years. An adult’s normal storage of vitamin B12 in the liver is approximately 2500 mcg. Newborns of mothers with normal B12 stores have body stores of only 25 mcg, which is thought to be enough to cover all of their metabolic needs in their first year of life. However, infants who are born to mothers with B12 deficiency due to any cause (ie, vegetarianism, autoimmune pernicious anemia, celiac disease, Helicobacter pylori, Crohn’s disease, gastric bypass, partial ileectomy, eating disorders, or use of proton-pump inhibitors, histamine2 blockers, metformin, or nitrous oxide [or abuse]) or who are exclusively breast-fed may have significantly less stored B12 and can develop a deficiency within the first year of life. Even infants who are formula-fed by these mothers may have suboptimal B12 levels, because the amount of B12 in their formula may not be enough to correct their deficiency.

Compared with adults, infants with B12 deficiency typically have a much more rapid onset of symptoms. Many children are deficient even before birth, because their mothers have an unidentified B12 deficiency, and the existing deficiency is worsened when the deficient mom breast-feeds. Other children are deficient because of 1 of several genetic defects causing inborn errors of B12 metabolism.

If it goes unrecognized in infancy, treating the disorder later at the toddler stage can result in rapid improvement, but some areas of the brain may be permanently injured, giving rise to fine motor difficulties, lower IQ, speech and language deficits, developmental delay, and behavioral problems. The extent of recovery and level of post-treatment functioning depend on the age at which the B12 deficiency began, its severity, how long it was present, and at what age treatment was instituted.

When breast-feeding mothers deficient in B12 switch their infants to formula or table foods, the infants may obtain sufficient B12 from these foods, but not enough to correct the existing deficiency. The minute amounts of B12 in the foods will protect a child from failure to thrive or death, but are suboptimal for the B12 needed for critical brain growth and development.

A 14-month-old boy was brought to an emergency department comatose on arrival. Severe B12 deficiency was diagnosed, with gross brain atrophy demonstrated by MRI. The boy regained consciousness within hours of treatment, and by day 3 of B12 injections, he was able to walk, eat, and drink, and was discharged. A brain MRI 10 weeks after treatment revealed that all structural brain abnormalities had disappeared, but the boy continued to show nerve damage. At 2 years of age he still displayed psychomotor retardation, agitation, and poor concentration. He could not speak any words.1

Role of Prenatal Vitamins

Physicians and other health care providers may mistakenly believe that prenatal vitamins significantly reduce the risk of B12 deficiency in pregnancy, but they do not contain enough vitamin B12 to correct an existing deficiency. The FDA fortified all cereals and grains with folic acid in 1998 to help decrease birth defects, and women are prescribed high-dose folic acid during pregnancy. Folic acid masks the signs of anemia and macrocytosis. Surprisingly, women are not being screened for B12 deficiency before conception, during pregnancy, or while breast-feeding—and as a result are receiving substandard care. B12 deficiency is also linked to neural tube defects, preeclampsia, and miscarriages.2,3

A 15-month-old child was diagnosed with severe B12 deficiency and presented with failure to thrive and developmental delay. A brain MRI revealed global cerebral atrophy, grossly elevated urinary methylmalonic acid, and a low B12 level. Hydroxocobalamin injections were immediately begun. At 28 months, the patient’s fine motor skills were at the 9-month level and his gross motor skills were comparable to those of an 18-monthold child. His expressive language was at a 10-month level and his receptive language was at a 12-month level. At 32 months, he had made developmental progress, but continued to have developmental delays, especially in speech and language.4

Learning and behavioral disabilities and autism spectrum disorders have multiple causes, and B12 deficiency is only 1 piece of the puzzle. Yet it is often overlooked. In fact, it is easily treated and certainly preventable. Given the epidemic of these disorders and the devastating social and financial costs, it is crucial that we explore the B12 link. As a health care provider involved with children, remember the ABCs—Autism B12 Connection—because an early diagnosis can save a child and his or her family from a lifetime of disability and hardship.5

Sally M. Pacholok, RN, BSN, has been researching cobalamin (vitamin B12) deficiency and practicing emergency nursing for 26 years. She is a frequent radio guest on nationally syndicated talk shows, lecturer, media personality, and co-author of Could It Be B12? An Epidemic of Misdiagnoses (2nd edition, 2011)—the winner of the Indie Excellence Award for best health book. Pacholok’s book was made into a documentary in 2012, and a screenplay has been completed to be made into a movie regarding Pacholok’s lifelong battle to improve the country’s health care system and expose substandard care. Pacholok is also an educator and public speaker for Superior Source Vitamins. Visit


  • von Schenck U, ender-Götze C, Koletzko B. Persistence of neurological damage induced by dietary vitamin B-12 deficiency in infancy. Arch Dis Child. 1997;77:137-139.
  • Molloy AM, Kirke PN, Troendle JF, et al. Maternal vitamin B12 status and risk of neural tube defects in a population with high neural tube defect prevalence and no folic acid fortification. Pediatrics. 2009;123:917-923.
  • Thompson MD, Cole DE, Ray JG. Vitamin B-12 and neural tube defects: the Canadian experience. Am J Clin Nutr. 2009;89(suppl):697S-701S.
  • Centers for Disease Control and Prevention. Neurologic impairment in children associated with maternal dietary deficiency of cobalamin—Georgia, 2001. MMWR Morb Mortal Wkly Rep. 2003;52(4):61-64.
  • Pacholok SM, Stuart JJ. Could It Be B12? An Epidemic of Misdiagnoses. 2nd ed. Quill Driver Books—Linden Publishing; 2011.

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