The genetic basis of autosomal recessive mental retardation (ARMR) is extremely heterogeneous, and there is reason to suspect that the number of underlying gene defects may well go beyond 1,000. To date, however, only less than 10 genes have been implicated in non-specific/non-syndromic ARMR (NS-ARMR). As part of an ongoing systematic study aiming to identify further ARMR genes, we investigated a consanguineous family with three patients with NS-ARMR. By linkage analysis and subsequent mutation screening we identified a novel nonsense mutation (c.163C > T [p.Q55X]) in the second exon of the TUSC3 gene. This is the third MR causing defect in TUSC3 to be described and the second independent mutation in this gene in a cohort of more than 200 ARMR families from the Iranian population. This argues for a more prominent role of TUSC3 in the etiology of this genetically heterogeneous disorder as compared to most of the other so far identified ARMR genes.

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Objective: This study aimed to evaluate the quality of life and related factors in mothers of children with Down syndrome. Methods:The study method was correlation-survey (sectional). Sampling was based on the available population. The research population consisted of all mothers of children with Down syndrome referred to the Down Syndrome Center: out of them 70 mothers of children with Down syndrome were randomly selected for study sample. Research tools were the WHO "quality of life" questionnaire, as well as a demographic and background information questionnaire. Data were analyzed using SPSS-16 software and ANOVA, multiple regression analysis and t-test. Results:The results showed a significant association of physical health and environmental health with the housing type (P<0.05). So that mothers living in private houses have higher physical and environmental health than those who live in rental houses. But, There were no significant relationship between the independent variables and the other subscales and total score of "quality of life" (P>0.05). Conclusion:People's negative attitude toward some disabilities and limitations, society's little information, inappropriate cultural, social, and economic conditions, and insufficient available resources can be the most important factors affecting the quality of life. It is recommended that the relevant organizations provide services and conditions for mothers of children with Down syndrome in order to improve their quality of life and health.

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To the best knowledge of the authors there is no study on nonlinear brain dynamics of down syndrome (DS) patients, whereas brain is a highly complex and nonlinear system. In this study, fractal dimension of EEG, as a key characteristic of brain dynamics, showing irregularity and complexity of brain dynamics, was used for evaluation of the dynamical changes in the DS brain. The results showed higher fractality of the DS brain in almost all regions compared to the normal brain, which indicates less centrality and higher irregular or random functioning of the DS brain regions. Also, laterality analysis of the frontal lobe showed that the normal brain had a right frontal laterality of complexity whereas the DS brain had an inverse pattern (left frontal laterality). Furthermore, the high accuracy of 95.8 % obtained by enhanced probabilistic neural network classifier showed the potential of nonlinear dynamic analysis of the brain for diagnosis of DS patients. Moreover, the results showed that the higher EEG fractality in DS is associated with the higher fractality in the low frequencies (delta and theta), in broad regions of the brain, and the high frequencies (beta and gamma), majorly in the frontal regions.