Histidinemia and infantile autism.
A 1979 case report linking high blood histidine to autism has been overtaken by larger studies showing amino-acid deficits, not excesses, in children with ASD.
01Research in Context
What this study did
Doctors wrote up one child with autism who also had high blood histidine.
They asked: could this extra amino acid help cause autism?
No treatment was tested—this was just a medical note.
What they found
The team saw high histidine in one autistic child.
They said the link might be worth more study.
That was the whole finding.
How this fits with other research
Katz et al. (2003) checked plasma amino acids in many kids. They found low levels, not high, when children ate restricted diets.
Tirouvanziam et al. (2012) looked at a full panel of amino acids. They saw lower polar neutral acids and leucine in autism, again not high.
Zhu et al. (2022) used gut samples and still found disrupted amino-acid paths. Together these newer studies extend the 1979 hint but flip the direction: kids with autism tend to run low, not high, in several amino acids.
Why it matters
One old case note cannot guide your practice. The pattern that keeps showing up is low amino acids, especially when kids avoid foods. Before you order special labs, check diet history and think about nutrition first.
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Review the diet log of any child with autism on a restricted eating plan and flag it for the dietitian if protein foods are limited.
02At a glance
03Original abstract
A 10-year-old boy first showed features of infantile autism at age 24 months. Histidinemia was also diagnosed, with histidine blood levels seven times higher than the upper normal values. If the coexistence of autism and histidinemia was not coincidental, histidinemia may have constituted a necessary but not sufficient factor leading to the clinical condition of autism. Other members of the patient's family had high blood levels of histidine, but did not show symptoms that have been related to histidinemia.
Journal of autism and developmental disorders, 1979 · doi:10.1007/BF01531292