Clinical spectrum in multiple families with primary COQ10 deficiency.

Coenzyme Q10/ COQ10 , an essential cofactor in the electron-transport chain is involved in ATP production. Primary COQ10 deficiency is clinically and genetically a heterogeneous group of mitochondrial disorders caused by defects in the COQ10 synthesis pathway. Its mode of inheritance is autosomal recessive and it is characterized by metabolic abnormalities and multisystem involvement including neurological features. Mutations in 10 genes have been identified concerning this group of diseases, so far. Among those, variants of the COQ7 gene are very rare and confined to three patients with Asian ancestry. Here, we present the clinical features and results of whole-exome sequencing (WES) of three Iranian unrelated families affected by primary COQ10 deficiency. Three homozygous variants in COQ2, COQ4, and COQ7 genes were identified. Candidate variants of the COQ2 and COQ4 genes were novel and associated with the cerebellar signs and multisystem involvement, whereas, the known variant in COQ7 was associated with a mild phenotype that was initially diagnosed as hereditary spastic paraplegia (HSP). This variant has already been reported in a Canadian girl with similar presentations that also originated from Iran suggesting both patients may share a common ancestor. Due to extensive heterogeneity in this group of disorders, and overlap with other mitochondrial/neurological disorders, WES may be helpful to distinguish primary coenzyme Q10 deficiency from other similar conditions. Given that some features of primary coenzyme Q10 deficiency may improve with exogenous COQ10 , early diagnosis is very important.

Polymorphisms of cystathionine beta-synthase gene are associated with susceptibility to sepsis.

Sepsis is the systemic inflammatory host response to infection. Cystathionine beta-synthase (CBS)-dependent homocysteine (Hcy) pathway was demonstrated to affect disease severity and mortality in patients with severe sepsis/septic shock. Independent studies identified a single-nucleotide polymorphism (SNP, rs6586282, hg19 chr21:g.44478497C>T) in intron 14 of the CBS-coding gene (CBS) associated with Hcy plasma levels. We aimed to describe the association of this SNP and variants of a splice donor-affecting variable-number tandem repeat (VNTR, NG_008938.1:g.22763_22793[16_22]) 243 bp downstream of rs6586282 with severe human sepsis. We analyzed the VNTR structure and genotyped variants of rs6586282 and a neighboring SNP (rs34758144, hg19 chr21:g.44478582G>A) in two case-control studies including patients with severe sepsis/septic shock from Germany (n=168) and Greece (n=237). In both studies, we consistently observed an association of CBS VNTR alleles with sepsis susceptibility. Risk linearly increased with number of tandem repeats (per allele odds ratio in the adjusted analysis 1.34; 95% confidence interval (CI)=1.17-1.55; P<0.001). Association had also been shown for rs34758144 whose risk allele is in linkage disequilibrium with one long VNTR allele (19 repeat). In contrast, we observed no evidence for an effect on 28-day survival in patients with severe sepsis/septic shock (per allele hazard ratio in the adjusted analysis for VNTR 1.10; 95% CI=0.95-1.28; P=0.20). In a minigene approach, we demonstrated alternative splicing in distinct VNTR alleles, which, however, was independent of the number of tandem units. In conclusion, there is no ordinary conjunction between human CBS and severe sepsis/septic shock, but CBS genotypes are involved in disease susceptibility.

Lack of Association between the MEF2A Gene and Coronary Artery Disease in Iranian Families.

OBJECTIVE(S): Coronary artery disease (CAD) which may lead to myocardial infarction (MI) is a complex one. Great effort has been devoted to identification of genes that increase susceptibility to CAD or provide protection. A 21-bp deletion in the MEF2A gene, which encodes a member of the myocyte enhancer factor 2 family of transcription factors, has been reported in patients of a single pedigree that exhibited autosomal-dominant inheritance of CAD. Subsequent analysis of genetic variants within the gene in CAD and MI case-control settings produced inconsistent results. Here, we aimed at assessing the contribution of MEF2A to CAD in a cohort of Iranian CAD patients. MATERIALS AND METHODS: Exon 11 of MEF2A wherein the above mentioned 21-bp deletion and a polyglutamine (CAG)n polymorphism are positioned was sequenced by the dideoxy-nucleotide termination protocol. In 52 CAD patients from 12 families (3-7 affected members per family) and 76 Iranian control individuals. All exons of the gene were sequenced in 10 patients and 10 controls. RESULTS: The 21-bp deletion was observed neither among the patients nor the control individuals. Four alleles of the polyglutamine (CAG)n polymorphism were found, but there were no significant differences in allelic frequencies between patients and controls. Sequencing of all exons of MEF2A revealed the presence of 12 novel sequence variations in introns and flanking regions of MEF2A gene, not associated with disease status. CONCLUSION: Our data do not support a role for MEF2A in coronary artery disease in the Iranian patients studied.