Glutaric acidemia, type I, missed by newborn screening in an infant with dystonia following promethazine administration.

We report a child initially diagnosed with promethazine-induced dystonia despite a lack of response to diphenhydramine therapy. On further evaluation, the child was diagnosed with glutaric acidemia, type I (GA-I), an autosomal recessive inborn error of metabolism caused by the deficiency of glutaryl-CoA dehydrogenase. The characteristic clinical feature of GA-I is an acute encephalopathic and neurologic crisis typically occurring during a catabolic state. Despite slow improvement, many patients do not fully recover from a neurologic crisis, and residual neurologic morbidity can be significant. Although newborn screening using tandem mass spectrometry is expected to enable presymptomatic diagnosis of GA-I, this patient was not detected by newborn screening with tandem mass spectrometry. Therefore, a high suspicion of GA-I must be maintained in the evaluation of childhood dystonia, even when newborn screening results are reportedly normal.

Duke Scholars

Author David Stuart Millington Pediatrics, Medical Genetics

Author Dwight D. Koeberl Pediatrics, Medical Genetics