Mutational landscape of phenylketonuria in Iran

To date more than 1000 different variants in the PAH gene have been identified in patients with phenylketonuria (PKU). In Iran, several studies have been performed to investigate the genetics bases of the PKU in different parts of the country. In this study, we have analysed and present an update of the mutational landscape of the PAH gene as well as the population genetics and frequencies of detected variants for each cohort. Published articles on PKU mutations in Iran were identified through a comprehensive PubMed, Google Scholar, Web of Science (ISI), SCOPUS, Elsevier, Wiley Online Library and SID literature search using the terms: "phenylketonuria", "hyperphenylalaninemia", and "PKU" in combination with "Iran", "Iranian population", "mutation analysis", and "Molecular genetics". Among the literature-related to genetics of PKU, 18 studies were on the PKU mutations. According to these studies, in different populations of Iran 1497 patients were included for mutation detection that resulted in detection of 129 different mutations. Results of genetic analysis of the different cohorts of Iranian PKU patients show that the most prevalent mutation in Iran is the pathogenic splice variant c.1066-11G > A, occurring in 19.54% of alleles in the cohort. Four other common mutations were p.Arg261Gln, p.Pro281Leu, c.168 + 5G > C and p.Arg243Ter (8.18%, 6.45%, 5.88% and 3.7%, respectively). One notable feature of the studied populations is its high rate of consanguineous marriages. Considering this feature, determining the prevalent PKU mutations could be advantageous for designing screening and diagnostic panels in Iran.

Inherited deletion of 9p22.3-p24.3 and duplication of 18p11.31-p11.32 associated with neurodevelopmental delay: Phenotypic matching of involved genes

We describe a 3.5-year-old Iranian female child and her affected 10-month-old brother with a maternally inherited derivative chromosome 9 [der(9)]. The postnatally detected rearrangement was finely characterized by aCGH analysis, which revealed a 15.056 Mb deletion of 9p22.3-p24.3p22.3 encompassing 14 OMIM morbid genes such as DOCK8, KANK1, DMRT1 and SMARCA2, and a gain of 3.309 Mb on 18p11.31-p11.32 encompassing USP14, THOC1, COLEC12, SMCHD1 and LPIN2. We aligned the genes affected by detected CNVs to clinical and functional phenotypic features using PhenogramViz. In this regard, the patient's phenotype and CNVs data were entered into PhenogramViz. For the 9p deletion CNV, 53 affected genes were identified and 17 of them were matched to 24 HPO terms describing the patient's phenotypes. Also, for CNV of 18p duplication, 22 affected genes were identified and six of them were matched to 13 phenotypes. Moreover, we used DECIPHER for in-depth characterization of involved genes in detected CNVs and also comparison of patient phenotypes with 9p and 18p genomic imbalances. Based on our filtration strategy, in the 9p22.3-p24.3 region, approximately 80 pathogenic/likely pathogenic/uncertain overlapping CNVs were in DECIPHER. The size of these CNVs ranged from 12.01 kb to 18.45 Mb and 52 CNVs were smaller than 1 Mb in size affecting 10 OMIM morbid genes. The 18p11.31-p11.32 region overlapped 19 CNVs in the DECIPHER database with the size ranging from 23.42 kb to 1.82 Mb. These CNVs affect eight haploinsufficient genes.

Disregulation of miR-216a and miR-217 in Gastric Cancer and Their Clinical Significance

OBJECTIVE

The majority of gastric cancer (GC) diagnoses occur at the middle or late stage of the disease, indicating that finding novel biomarkers that could be detectable at earlier stage is urgently needed. Accumulating studies have shown that microRNAs, a class of tiny single-stranded RNAs, play important roles in multiple biological processes including cancer development. The present study aimed to evaluate the effect of miR-216a and miR-217 in GC.

MATERIAL AND METHODS

The real-time quantitative reverse-transcription PCR was exploited to identify and compare the expression levels of miR-216a and miR-217 in 37 pairs of samples of gastric cancer tissue and adjacent normal tissue. Superimposed on this, the potential relationship between miR-216a/217 levels and clinicopathological parameters in patients suffering GC was explored.

RESULTS

The results obtained from this study showed that the miR-216a is significantly upregulated in gastric cancer tissues, compared with adjacent normal tissues, but the altered expression of miR-217 was not significant. For miR-216a/217, no significant correlations were detected between expression levels of these miRNAs and clinical and pathological characteristics of patients.

CONCLUSION

This prospective study proposes that upregulation of miR-216a might represent an important mechanism for the development of gastric cancer.

Deregulated expression of HDAC3 in colorectal cancer and its clinical significance

BACKGROUND

To date, 4 classes of histone deacetylases (HDACs) have been identified in humans. Class I HDACs are zinc-dependent and NAD+-independent enzymes, and include 4 isoforms closely related to yeast RPD3: HDAC1, 2, 3, and 8.

OBJECTIVES

The aims of the study were to quantitatively evaluate the expression of HDAC3 in colorectal cancer (CRC) and to correlate its expression levels with clinicopathological parameters.

MATERIAL AND METHODS

We characterized expression patterns of HDAC3 as class I HDAC isoforms in a cohort of 48 CRC patients by quantitative (real-time) reverse transcription polymerase chain reaction (RT-PCR). In addition, the potential relationship between HDAC3 expression levels and clinicopathological parameters in patients suffering from CRC was explored.

RESULTS

We found that HDAC3 was highly expressed in colorectal tumors compared to normal colorectal tissues (p < 0.05). Furthermore, we found significant correlations between HDAC3 expression levels and tumor differentiation grades (p < 0.05).

CONCLUSIONS

In this prospective study we identified a pronounced HDAC3 expression pattern in CRC. Our findings support an important role of HDAC3 as a complementary molecular marker for existing histopathological diagnostic elements; it might also have applications in prognostic and targeted therapy. Furthermore, HDAC3 can be used as a biomarker to differentiate between tumor borders and margins, and it may also be useful for characterizing field cancerization in CRC.

A unique profile of adenomatous polyposis coli gene mutations in Iranian patients suffering sporadic colorectal cancer

OBJECTIVE

Colorectal cancer (CRC) is one of the most common and aggressive cancers worldwide. The majority of CRC cases are sporadic that caused by somatic mutations. The Adenomatous Polyposis Coli (APC; OMIM 611731) is a tumor suppressor gene of Wnt pathway and is frequently mutated in CRC cases. This study was designed to investigate the spectrum of APC gene mutations in Iranian patients with sporadic colorectal cancer.

MATERIALS AND METHODS

In this descriptive study, Tumor and normal tissue samples were obtained from thirty randomly selected and unrelated sporadic CRC patients. We examined the hotspot region of the APC gene in all patients. Our mutation detection method was direct DNA sequencing.

RESULTS

We found a total of 8 different APC mutations, including two nonsense mutations (c.4099C>T and c.4348C>T), two missense mutations (c.3236C>G and c.3527C>T) and four frame shift mutations (c.2804dupA, c.4317delT, c.4464_4471delATTACATT and c.4468_4469dupCA). The c.3236C>G and c.4468_4469dupCA are novel mutations. The overall frequency of APC mutation was 26.7% (8 of 30 patients).

CONCLUSION

This mutation rate is lower in comparison with previous studies from other countries. The findings of present study demonstrate a different APC mutation spectrum in CRC patients of Iranian origin compared with other populations.

A preliminary mutation analysis of phenylketonuria in southwest Iran

Phenylketonuria (PKU) is a heterogeneous and autosomal recessive metabolic disorder that is mainly caused by mutations in the hepatic phenylalanine hydroxylase (PAH) gene. This study was designed to identify PAH mutations within exons 6, 7, and 10-12 in PKU patients from southwest Iran. Forty Iranian patients with clinical and biochemically confirmed PKU were enrolled. The exons were sequenced directly and 13 different mutations were identified including I224T, S231P, R176X, c.592_613del22, R243X, R252W, R261Q, Y356X, V388M, IVS10-11G>A, IVS11+1G>C, IVS11-2A>G, and Q375R, which were associated with 23 genotypes. A novel sequence variant, Q375R (c.1124A>G), was detected in exon 11. In one patient, a typical genotype with more than two mutations (R243X/S231P/S231P) was found. Seven different polymorphisms and three new variants were also detected in intron regions of PAH. A high mutation spectrum was predicted in the southwestern region of Iran due to its ethnic heterogeneity, especially the Khuzestan Province. The detection of 13 different mutations, corresponding to a mutation detection rate of 53.75%, confirmed this phenomenon.

Characterization of norovirus-associated traveler's diarrhea

BACKGROUND

Traveler's diarrhea is the most common medical complaint of international visitors to developing regions. Previous findings suggested that noroviruses (NoVs) are an underappreciated cause of traveler's diarrhea. METHODS. In the present study, we sought to define the presence of NoVs in 320 acute diarrheic stool samples collected from 299 US students who traveled to Guadalajara, Cuernavaca, or Puerto Vallarta, Mexico, during the period from 2007 through 2008. Conventional and quantitative real-time polymerase chain reaction assays were used to detect and determine NoV loads in stool samples. NoV strains were characterized by purification of viral RNA followed by sequencing of the viral capsid protein 1 gene. Sequences were compared using multiple sequence alignment, and phylogenetic trees were generated to evaluate the evolutionary relatedness of the viral strains associated with cases of traveler's diarrhea.

RESULTS

NoV RNA was detected in 30 (9.4%) of 320 samples. Twelve strains belonged to genogroup I, and 18 strains belonged to genogroup II. NoV prevalence was higher in the winter season than in the summer season (23% vs 7%, respectively; P = .001). The cDNA viral loads of genogroup I viruses were found to be 500-fold higher than those of genogroup II strains. Phylogenetic analysis revealed a diverse population of NoV strains over different locations and years.

CONCLUSIONS

NoV strains are important causes of traveler's diarrhea in Mexico, especially during the wintertime, and US students in Mexico may represent a suitable group for future NoV vaccine efficacy trials.