The Value of 1H-MRS and MRI in Combined Methylmalonic Aciduria and Homocystinuria

NMR Spectroscopy in Diagnosis and Monitoring of Methylmalonic and Propionic Acidemias

Although both localized nuclear magnetic resonance spectroscopy (MRS) and non-localized nuclear magnetic resonance spectroscopy (NMR) generate the same information, i.e., spectra generated by various groups from the structure of metabolites, they are rarely employed in the same study or by the same research group. As our review reveals, these techniques have never been applied in the same study of methylmalonic acidemia (MMA), propionic acidemia (PA) or vitamin B12 deficiency patients. On the other hand, MRS and NMR provide complementary information which is very valuable in the assessment of the severity of disease and efficiency of its treatment. Thus, MRS provides intracellular metabolic information from localized regions of the brain, while NMR provides extracellular metabolic information from biological fluids like urine, blood or cerebrospinal fluid. This paper presents an up-to-date review of the NMR and MRS studies reported to date for methylmalonic and propionic acidemias. Vitamin B12 deficiency, although in most of its cases not inherited, shares similarities in its metabolic effects with MMA and it is also covered in this review.

Follow-up study of neuropsychological scores of infant patients with cobalamin C defects and influencing factors of cerebral magnetic resonance imaging characteristics

Purpose

The purpose of this study was to investigate whether baseline cerebral magnetic resonance imaging (MRI) characteristics could predict therapeutic responsiveness in patients with cobalamin C (cblC) defects.

Materials and methods

The cerebral MRI results of 40 patients with cblC defects were evaluated by a neuroradiologist. Neuropsychological scores and imaging data were collected. Neuropsychological tests were performed before and after standardized treatment.

Results

Thirty-eight patients initially underwent neuropsychological testing [developmental quotient (DQ)]. CblC defects with cerebellar atrophy, corpus callosum thinning and ventricular dilation had significantly lower DQs than those without (P < 0.05). Through a multivariate linear stepwise regression equation after univariate analysis, ventricular dilation was the most valuable predictor of lower DQs. Thirty-six patients (94.7%) underwent follow-up neuropsychological testing. The pre- and post-treatment DQ values were not significantly different (Z = -1.611, P = 0.107). The post-treatment DQ classification (normal, moderately low, or extremely low) showed nearly no change compared to the pretreatment DQ classification (k = 0.790, P < 0.001).

Conclusion

Ventricular dilation, cerebral atrophy and corpus callosum thinning are the main MRI abnormalities of cblC defects, and these manifestations are significantly correlated with delayed development in children. MRI findings can be considered an important tool for determining the severity of cblC defects.

Effects of Virtual Reality Rehabilitation Training on Cognitive Function and Activities of Daily Living of Patients With Poststroke Cognitive Impairment: A Systematic Review and Meta-Analysis

OBJECTIVE

To determine the effects of virtual reality (VR) rehabilitation training on the cognitive function and activities of daily living (ADL) of patients with poststroke cognitive impairment (PSCI).

DATA SOURCES

Four Chinese databases and 6 English databases were systematically searched for studies published until August 31, 2021, by using Medical Subject Headings of the National Library of Medicine terms such as virtual reality, cognition disorders, cognitive dysfunction, and stroke and free terms such as virtual environment, VR, cognition impairment, cerebrovascular accident, and PSCI.

STUDY SELECTION

Randomized controlled trials treating PSCI with VR training were included. The control groups received conventional treatments such as conventional rehabilitation training and drug therapy; the experimental groups received VR rehabilitation training. The outcome measures were cognitive function and ADL.

DATA EXTRACTION

Two researchers independently extracted key information from eligible studies. The methodological quality of the studies was evaluated using the Cochrane Handbook for Systematic Reviews of Interventions v5.1.0. Meta-analysis was performed using RevMan v5.4. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines.

DATA SYNTHESIS

Twenty-one studies (1149 participants) were included. Meta-analyses found that compared with the control group, VR rehabilitation training increased Mini-Mental State Examination, Montreal Cognitive Assessment, Loewenstein Occupational Therapy Cognitive Assessment, Rivermead Behavioral Memory Test Second Edition, Barthel Index, Modified Barthel Index, and FIM scores; event-related potential 300 (P300) amplitude; and the N-acetylaspartate/creatinine (Cr) ratio on proton magnetic resonance spectroscopy (1H-MRS) and reduced P300 latency; Trail Making Test scores; and the choline-containing compounds/Cr ratio on 1H-MRS (all P<.05). These results indicated that VR training improved cognitive function and ADL in PSCI.

CONCLUSIONS

VR rehabilitation training promotes the rehabilitation of cognitive function and recovery of ADL in patients with PSCI and may be a good complementary approach to conventional cognitive interventions.

Spectrum of clinical manifestation of methylmalonic acidemia and homocystinuria in a family of six siblings: novel combination of transcobalamin receptor defect (CD320) and cblC deficiency (MMACHC)

Background

Methylmalonic acidemia with homocystinuria is caused by a rare inborn error of vitamin B12 (cobalamin) metabolism. There are four complementation classes of cobalamin defects cblC, cblD, cblF, and cblJ that are responsible for combined methylmalonic acidemia and homocystinuria.

Case presentation

We report a case of a Pakistani family composed of six children diagnosed with methylmalonic acidemia and homocystinuria (MMA + HCU). Mutation analysis of siblings revealed a variable combination of c.394C>T mutation in the MMACHC gene and c.262_264del in CD320 gene. All siblings had variable age of onset, initial symptomatology, the severity of disease, and response to treatment. The maximum age of presentation was 6.5 years and the minimum age was at birth. The spectrum of symptoms ranged from a subtle learning disability to global developmental delay within the same family. None of them had a seizure disorder, megaloblastic anemia, visual disturbance, and vascular events.CD320 defect itself is very rare, and only 12 cases have been reported so far. We report six cases, four of them had homozygous MMACHC variant c.394C>T and the other two had heterozygous MMACHC mutations in c.394C>T and c.262_264del in CD 320 genes. To date, neither such case has been reported in the literature or this compound heterozygous mutation.

Conclusion

Our case report emphasizes that the diagnosis of inherited metabolic disorder in a child obviates the need to screen all siblings for the same disorder.