Cui Y, Wang X, Li Y, Wei D, Dongmei J and Wang H
Objective: We reviewed the clinical manifestations and examination results of one infant with 2-methyl-3- hydroxybutyryl-CoA dehydrogenase deficiency (MHBDD), intending to enhance the understanding, diagnosis and treatment of MHBD. Method: The clinical manifestations and results of laboratory tests, tandem mass spectrometry of the blood sample, gas chromatography-mass spectrometry of the urine sample, chest X-ray, color Doppler examination, brain MRI and EEG as well as the treatment of this case were analyzed retrospectively. Result: This infant, aged 3 years old, mainly presented the symptoms of diarrhea and vomiting initially, and later lethargy, disturbance of consciousness, dyspnea and incorrigible metabolic acidosis. Brain MRI indicated mild ventriculomegaly and widening of sulci bilaterally. Borderline EEG was observed, with several sharp wave discharges in the frontal and central regions of the brain. Tandem mass spectrometry of the blood sample indicated increased levels of aspartic acid and other amino acids; gas chromatography of the urine sample indicated an obvious increase of 2-methyl-3-hydroxybutyric acid, but the levels of 3-methylcrotonyl-glycine or 2-methyl-acetoacetic acid were basically normally. Gene detection revealed p.R130C mutation in exon 4 of the HADH2 gene. Conclusion: As a rare disease, MHBDD may be suspected for infants presenting with incorrigible metabolic acidosis and hyperammonemia or neurological symptoms such as lethargy and disturbance of consciousness for unknown reasons. Examination techniques including tandem mass spectrometry, gas chromatography-mass spectrometry of the blood and urine samples and gene detections can be used for early diagnosis and treatment.