Genotype-phenotype associations in hereditary spastic paraplegia: a systematic review and meta-analysis on 13,570 patients.

AIMS: The hereditary spastic paraplegias (HSPs) are a heterogeneous group of inherited neurodegenerative disorders. Although, several genotype-phenotype studies have carried out on HSPs, the association between genotypes and clinical phenotypes remain incomplete since most studies are small in size or restricted to a few genes. Accordingly, this study provides the systematic meta-analysis of genotype-phenotype associations in HSP. METHODS AND RESULTS: We retrieved literature on genotype-phenotype associations in patients with HSP and mutated SPAST, REEP1, ATL1, SPG11, SPG15, SPG7, SPG35, SPG54, SPG5. In total, 147 studies with 13,570 HSP patients were included in our meta-analysis. The frequency of mutations in SPAST (25%) was higher than REEP1 (3%), as well as ATL1 (5%) in AD-HSP patients. As for AR-HSP patients, the rates of mutations in SPG11 (18%), SPG15 (7%) and SPG7 (13%) were higher than SPG5 (5%), as well as SPG35 (8%) and SPG54 (7%). The mean age of AD-HSP onset for ATL1 mutation-positive patients was earlier than patients with SPAST, REEP1 mutations. Also, the tendency toward younger age at AR-HSP onset for SPG35 was higher than other mutated genes. It is noteworthy that the mean age at HSP onset ranged from infancy to adulthood. As for the gender distribution, the male proportion in SPG7-HSP (90%) and REEP1-HSP (78%) was markedly high. The frequency of symptoms was varied among patients with different mutated genes. The rates of LL weakness, superficial sensory abnormalities, neuropathy, and deep sensory impairment were noticeably high in REEP1 mutations carriers. Also, in AR-HSP patients with SPG11 mutations, the presentation of symptoms including pes cavus, Neuropathy, and UL spasticity was higher. CONCLUSION: Our comprehensive genotype-phenotype assessment of available data displays that the mean age at disease onset and particular sub-phenotypes are associated with specific mutated genes which might be beneficial for a diagnostic procedure and differentiation of the specific mutated genes phenotype among diverse forms of HSP.

SUCLG1 mutations and mitochondrial encephalomyopathy: a case study and review of the literature.

The mitochondrial encephalomyopathies represent a clinically heterogeneous group of neurodegenerative disorders. The clinical phenotype of patients could be explained by mutations of mitochondria-related genes, notably SUCLG1 and SUCLA2. Here, we presented a 5-year-old boy with clinical features of mitochondrial encephalomyopathy from Iran. Also, a systematic review was performed to explore the involvement of SUCLG1 mutations in published mitochondrial encephalomyopathies cases. Genotyping was performed by implementing whole-exome sequencing. Moreover, quantification of the mtDNA content was performed by real-time qPCR. We identified a novel, homozygote missense variant chr2: 84676796 A > T (hg19) in the SUCLG1 gene. This mutation substitutes Cys with Ser at the 60-position of the SUCLG1 protein. Furthermore, the in-silico analysis revealed that the mutated position in the genome is well conserved in mammalians, that implies mutation in this residue would possibly result in phenotypic consequences. Here, we identified a novel, homozygote missense variant chr2: 84676796 A > T in the SUCLG1 gene. Using a range of experimental and in silico analysis, we found that the mutation might explain the observed phenotype in the family.

Deregulation of long noncoding RNA SNHG17 and TTC28-AS1 is associated with type 2 diabetes mellitus.

Long noncoding RNAs (lncRNAs) have emerged as key players in several biological processes and complex diseases including type 2 diabetes mellitus (T2DM). The purpose of this study was to investigate the expression levels of SNHG17 and TTC28-AS1 in T2DM patients. Quantitative real-time RT-PCR analysis was performed using peripheral blood mononuclear cells (PBMCs) samples from patients diagnosed with T2DM and healthy controls. Binary logistic regression analysis was carried out to determine the odds of development of T2DM based on expression levels of lncRNAs and clinical characteristic of the subjects. Spearman's correlation analysis was used to clarify the correlation between SNHG17 and TTC28-AS1 expressions to metabolic features. We found that SNHG17 and TTC28-AS1were down-regulated in the T2DM group compared to the healthy control group. The logistic regression revealed that body mass index (BMI), systolic blood pressure (SBP), fasting blood glucose (FBG) and TTC28-AS1 expression substantially affect T2DM susceptibility. Furthermore, expression of SNHG17 was negatively correlated with high-density lipoprotein cholesterol (HDL-C) and expression of TTC28-AS1 was positively correlated with low-density lipoprotein cholesterol (LDL-C). Decreased expressions of lncRNAs TTC28-AS1 and SNHG17 in T2DM are possibly associated with the development of T2DM.

Clinical significance of long noncoding RNA VIM-AS1 and CTBP1-AS2 expression in type 2 diabetes.

BACKGROUND/AIMS: The risk of type 2 diabetes (T2D) is determined by a combination of genetic and environmental factors. Multiple studies have proposed that long noncoding RNAs (lncRNAs) are crucial molecules in regulating several biological processes and complex diseases. The study was aimed at investigating the association between the expression levels of lncRNA VIM-AS1, lncRNA CTBP1-AS2, and T2D susceptibility. METHODS: lncRNA VIM-AS1 and lncRNA CTBP1-AS2 in the peripheral blood mononuclear cell (PBMC) of 100 healthy individuals and 100 T2D patients were collected for Quantitative Real-Time RT-PCR analysis. A logistic regression was performed to understand whether the likelihood of T2D can be predicted based on the expression levels of lncRNA VIM-AS1 and lncRNA CTBP1-AS2. Receiver operating characteristic (ROC) analysis was also performed to determine the statistical analysis of VIM-AS1 and CTBP1-AS2 levels in 200 samples. RESULTS: Our results display that decreased levels of VIM-AS1 and CTBP1-AS2 in PBMC were associated with diabetes in Iranian population. The logistic regression revealed that Systolic blood pressure (SBP), low-density lipoprotein cholesterol (LDL-C), Fasting blood glucose (FBG) and CTBP1-AS2 are substantial predictors of T2D. The ROC analysis of CTBP1-AS2 revealed the area under the ROC curve (AUC) of 0.68 with a sensitivity of 58.7% and specificity of 75.3% in distinguishing nondiabetic from diabetic subjects. The ROC analysis of VIM-AS1 determined AUC of 0.63 with a sensitivity of 56.1% and specificity of 68.37% in distinguishing the two diagnostic groups. CONCLUSION: lncRNA VIM-AS1 and lncRNA CTBP1-AS2 expression levels are associated with T2D susceptibility.