The TT genotype of methylenetetrahydrofolate reductase 677C>T polymorphism increases the susceptibility to pediatric ischemic stroke: meta-analysis of the 822 cases and 1,552 controls

The 677C>T polymorphism within methylenetetrahydrofolate reductase (MTHFR) gene is related to an elevated level of homocysteine. Thus it may be considered as a genetic risk factor in ischemic stroke. Apparently studies of this type of polymorphism in childhood stroke have shown conflicting results. We performed meta-analysis of all the data that are available in relation with MTHFR polymorphism and the risk of ischemic stroke in children. We searched PubMed (last search dated December 2010) using “MTHFR polymorphism”, “ischemic stroke” “child”, “children”, “pediatric stroke” as keywords and reference lists of studies and reviews on the topic. Finally, 15 case–control studies corresponded to the inclusion criteria for meta-analysis. These studies involved the total number of 822 children and adolescents after ischemic stroke and 1,552 control subjects. Fixed or random effects models were used depending on the heterogeneity between the studies. The association between ischemic stroke and 677C>T polymorphism within MTHFR gene was observed in three of the studies. The pooled analysis showed that TT genotype of MTHFR gene is more common in stroke patients than in controls (p = 0.0402, odds ratio = 1.57, 95 % confidence interval 1.02–2.41). The Egger’s test did not reveal presence of a publication bias. The results based on a sizeable group of cases and controls have proved that the 677C>T polymorphism in MTHFR gene is associated with the development of ischemic stroke in children

The syndrome of deafness-dystonia: Clinical and genetic heterogeneity

The syndrome of deafness-dystonia is rare and refers to the association of hearing impairment and dystonia when these are dominant features of a disease. Known genetic causes include Mohr-Tranebjaerg syndrome, Woodhouse-Sakati syndrome, and mitochondrial disorders, but the cause frequently remains unidentified. The aim of the current study was to better characterize etiological and clinical aspects of deafness-dystonia syndrome. We evaluated 20 patients with deafness-dystonia syndrome who were seen during the period between 1994 and 2011. The cause was identified in only 7 patients and included methylmalonic aciduria, meningoencephalitis, perinatal hypoxic-ischemic injury, large genomic deletion on chromosome 7q21, translocase of inner mitochondrial membrane 8 homolog A (TIMM8A) mutation (Mohr-Tranebjaerg syndrome), and chromosome 2 open reading frame 37 (C2orf37) mutation (Woodhouse-Sakati syndrome). The age of onset and clinical characteristics in these patients varied, depending on the etiology. In 13 patients, the cause remained unexplained despite extensive work-up. In the group of patients who had unknown etiology, a family history for deafness and/or dystonia was present the majority of patients, suggesting a strong genetic component. Sensory-neural deafness always preceded dystonia. Two clinical patterns of deafness-dystonia syndrome were observed: patients who had an onset in childhood had generalized dystonia (10 of 13 patients) with frequent bulbar involvement, whereas patients who had a dystonia onset in adulthood had segmental dystonia (3 of 13 patients) with the invariable presence of laryngeal dystonia. Deafness-dystonia syndrome is etiologically and clinically heterogeneous, and most patients have an unknown cause. The different age at onset and variable family history suggest a heterogeneous genetic background, possibly including currently unidentified genetic conditions. (c) 2013 Movement Disorder Societ