Multimodal MR imaging in acute exacerbation of methylmalonic acidemia.

Methylmalonic acidemia (MMA) is a disorder of methylmalonic acid metabolism caused by impaired methylmalonyl CoA mutase. Neuroimaging shows symmetric hypodensity on CT, and T2 prolongation on MRI in the globus pallidus; however, there have been only a few reports on MR spectroscopy findings and no previous reports on arterial spin labeling (ASL), both of which could reflect neurochemical derangement in MMA. We herein report an 18-month-old Sri Lankan boy presented with severe acute exacerbation of MMA due to bacteremia of Salmonella sp. O7. MRI on the seventh day showed T1 and T2 prolongation with decreased diffusion in the bilateral globus pallidus. ASL revealed hyperperfusion in the bilateral globus pallidus. MR spectroscopy showed increased choline (Cho), myo-inositol (mIns), glutamine (Gln), and lactate (Lac) in the globus pallidus; and increased Gln and Lac in the white matter. The globus pallidus is the site of high energy demand around the age of 1 year. In severe acute exacerbation of MMA, increased anaerobic metabolism due to impaired mitochondrial function may lead to hyperperfusion in the globus pallidus to compensate for a disturbed energy supply. Increased Cho, mIns, and Lac in the globus pallidus may result from active demyelination, astrogliosis, and increased anaerobic metabolism. Increased Gln in the basal ganglia and white matter may reflect excitotoxicity.

Usefulness of BCOR gene mutation as a prognostic factor in acute myeloid leukemia with intermediate cytogenetic prognosis.

BCOR gene is a transcription regulatory factor that plays an essential role in normal hematopoiesis. The wider introduction of next-generation sequencing technology has led to reports in recent years of mutations in the BCOR gene in acute myeloid leukemia (AML), but the related clinical characteristics and prognosis are not sufficiently understood. We investigated the clinical characteristics and prognosis of 377 de novo AML cases with BCOR or BCORL1 mutation. BCOR or BCORL1 gene mutations were found in 28 cases (7.4%). Among cases aged 65 years or below that were also FLT3-ITD-negative and in the intermediate cytogenetic prognosis group, BCOR or BCORL1 gene mutations were observed in 11% of cases (12 of 111 cases), and this group had significantly lower 5-year overall survival (OS) (13.6% vs. 55.0%, P = 0.0021) and relapse-free survival (RFS) (14.3% vs. 44.5%, P = 0.0168) compared to cases without BCOR or BCORL1 gene mutations. Multivariate analysis demonstrated that BCOR mutations were an independent unfavorable prognostic factor (P = 0.0038, P = 0.0463) for both OS and RFS. In cases of AML that are FLT3-ITD-negative, aged 65 years or below, and in the intermediate cytogenetic prognosis group, which are considered to have relatively favorable prognosis, BCOR gene mutations appear to be an important prognostic factor.