Tehran University Medical Journal

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Background: Breast cancer is the most common cancer in women. Non-coding RNAs especially miRNAs have important regulatory roles in cancer. MiRNAs are 21-24 nucleotides which have different levels of expression between tumors and normal tissues. In this study, we have analyzed expression level of miR-520d in three different groups of breast cancer.
Methods: Fifty nine samples were divided into different groups according to their immunohistochemistry (IHC) classification: estrogen receptor (ER) positive and/or progesterone receptor (PR) positive group (as group I) human epidermal growth factor receptor 2 (HER2) positive group (as group II) and Triple negative group (as group III). After small RNA extraction from tissues, cDNAs were synthesized and Real time RT-PCR carried out using DNA binding dye. Expression levels were analyzed by LinRegPCR and REST software.
Results: MiR-520d under- expressed in all of three different groups. The expression ratio in groups I ,II, and III were 0.193, 0.167, 0.21, respectively, but only the result from group II was significant (P=0.017). According to the different clinicopathological status of breast cancer, miR-520d underexpressed significantly not only in patients with metastatic lymph node (P=0.019) but also in patients which have cancer at stage III (P=0.036). 
Conclusion: In this study, we found that miR-520d possibly acts as a tumor suppressor. It may be useful for diagnosis of tumor from normal tissue. In addition, miR-520d significantly underexpressed in HER-2 positive group of breast cancers. Therefore, it may be useful as an additional diagnostic test in this group of breast tumors along with other biomarkers.

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Background: About 15% of couples have fertility problems and male factor in fertility accounts for half of the cases. In vitro generation of germ cells introduces a novel approach to male infertility and provides an effective system in gene tracking studies, however many aspects of this process have remained unclear. We aimed to promote mouse embryonic stem cells (mESCs) differentiation into germ cells and evaluate its effectiveness with tracking the expression of the Testis specific 10 (Tsga10) during this process. Methods: This is an in vitro study that was performed in department of Medical Genetics in Tehran University of Medical Sciences from February 2012 to March 2013. Mouse embryonic stem cells were cultured on mouse embryonic fibroblast as feeder layer. Then mESCs were differentiated into germ cells in the presence of Retinoic Acid. Based on developmental schedule of the postnatal testis, samples were taken on the 7th, 12th and 25th days of the culture and were subjected to expression analysis of a panel of germ cell specific genes (Stra8 as pre-meiotic, Dazl and Sycp3‌ as meiotic and Protamin1 and Spata19 as Post-meiotic). Expression of Testis Specific Gene 10 (Tsga10) at RNA and protein levels was then analyzed. Results: It was shown that transition of embryonic stem cells from mitosis to meiosis occurred between 7th and 12th days of mESC culture and post-meiotic gene expression did not occur until 25th day of the culture. Results showed low level of Tsga10 expression in undifferentiated stem cells. During transition from meiotic to post-meiotic phase, Tsga10 expression increased in 6.6 folds. This finding is in concordance with in vivo changes during transition from pre-pubertal to pubertal stage. Localization of processed and unprocessed form of the related protein was similar to those in vivo as well. Conclusion: Expression pattern of Tsga10, as a gene with critical function in spermatogenesis, is similar during in vitro and in vivo germ cell generation. The results suggest that in vitro derived germ cells could be a trusted model to study genes behavior during spermatogenesis.

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Background: Autosomal recessive polycystic kidney disorder (ARPCKD) is one of the most prevalent hereditary disorders in neonates and children. Its frequency is between 1/6000 to 1/55000 births. In the most severe cases, it can be diagnosed prenatally by the presence of enlarged, echogenic kidneys and oligohydramnios. However, in the milder forms, clinical manifestations are usually detected in neonatal and childhood period. PKHD1 gene located on chromosome 6 is linked with this disorder. About half of detected mutations in this gene are missense ones. The largest protein product of this gene is called the FPC/polyductin complex (FPC). It is a single-membrane spanning protein whose absence leads to abnormal ciliogenesis in the kidneys.

Case presentation: Here we present a 5-year-old female patient affected with ARPCKD. She has been born to a non-consanguineous healthy Iranian parents. No similar disorder has been seen in the family. Prenatal history has been normal. In order to find the genetic background, DNA was extracted from patient's peripheral blood lymphocytes. PKHD1 gene exons and exon-intron boundaries were sequenced using next generation sequencing platform. Two novel variants have been detected in compound heterozygote state in the patient (c.6591C>A, c.8222C>A). Bioinformatics tools predicted these variants to be pathogenic.

Conclusion: In the present study, we detected two novel variants in PKHD1 gene in a patient with ARPCKD. The relatively mild phenotype of this patient is in accordance with the missense mutations found. Molecular genetic tools can help in accurate risk assessment as well as precise genotype-phenotype correlation establishment in families affected with such disorder to decrease the birth of affected individuals through preimplantation genetic diagnosis or better management of disorder.

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Background: Mental retardation is defined as impaired mental capacity and ability to comply with environmental and social conditions. Chromosomal abnormalities are the most important causes of mental retardation. Carriers of balanced chromosomal translocation are phenotypically normal, although they may be at risk of infertility, recurrent miscarriage or giving birth to mentally retarded children. These abnormalities are caused because chromosomes participated in the reciprocal translocations produce quadrivalents at meiosis. These quadrivalents segregate and lead to several different meiotic outcomes, just two of which are normal or balanced. Case Presentation: A consanguineous family with three mentally retarded daughters at the ages of 24, 18 and 10 years was referred to Comprehensive Medical Genetics Centre, Shiraz, Iran in 2015. Family history showed a case of unexplained infant death as well as a spontaneous abortion. Three survived siblings had hypotonia and severe developmental delay during infantile period. In addition, they suffer from primary amenorrhea. Two siblings have vesicoureteral reflux (VUR). Cytogenetic analysis of two patients showed 46,XX,t(6;12)(q23;q22),der(9)t(8;9)(q24;p24) with partial monosomy of chromosome 9 and partial trisomy of 8q24 segment, while the other patient had 46,XX,der(12)t(6;12)(q23;q22) with partial monosomy of 12q22qter and partial trisomy of 6q23qter segment. Their mother had two balanced chromosomal translocations (46, XX, t(6,12)(q21;q22), t(8,9)(q24;p24)). Conclusion: The above presented case is another example for the rare occurrence of double balanced chromosomal translocations in a phenotypically normal person. Although the most important causes of mental retardation in consanguineous marriages are autosomal recessive disorders, the role of chromosomal aberrations in mental retardation in these families must not be neglected. In other words, cytogenetic studies should be performed as a first line test in either situation.