Slow weight gain and unremarkably increased urine methylmalonic acid

Abstract

A 2-month-and-20-day-old girl was hospitalized because of slow weight gain for 20 days.The patient was diagnosed as anemia, pneumonia and neutrophils firstly, and showed no improvement during anti-infective therapy, blood transfusion, and leukopenia drugs.The urinary organic acid spectrum of the patient showed increased methylmalonic acid slightly, but the normal value was found by 4 tests, which was inconsistent with the typical methylmalonic aciduria.By analyzing clinical manifestations and plasma homocysteine, folic acid and vitamin B12 levels, she was considered to have intracellular cobalamin metabolic disorder.Then, normal diet, intramuscular injection of vitamin B12, and feeding calcium, betaine, and L-carnitine were given, and the girl′s symptoms were improved significantly.Latter gene analysis further showed that the patient had methylmalonic aciduria CblC type.Clinical manifestations of methylmalonic aciduria are complex and individually various, different therapies showed be applied to different causes.The value of urinary methylmalonic acid level alone cannot judge etiology; diagnosis should be based on blood amino acids and carnitine spectrum, homocysteine level and vitamin B12 level. Key words: Methylmalonic acid; Homocysteine; Vitamin B12; Anemia; Pneumonia