Mutation analysis of genes related to methylmalonic acidemia: identification of eight novel mutations.

Methylmalonic acidemia (MMA), an inherited metabolic disease, results from genetic defects in methylmalonyl-CoA mutase or any of the proteins involved in adenosylcobalamin synthesis. This enzyme is classified into several complementation groups and genotypic classes. In this work we explain the biochemical, structural and genetic analysis of 25 MMA patients, from Iran. The diagnosis was established by the measurement of propionylcarnitine in blood using tandem mass spectrometry and confirmed using a gas chromatography-flame ionization detector. Using clinical, biochemical, structural and molecular analyses we identified 15 mut MMA, three cblA, one cblB, and four cblC-deficient patients. Among mutations identified in the MUT gene (MUT) only one, the c.1874A>C (p.D625A) variant, is likely a mut- mutation. The remaining mutations are probably mut0. Here, we present the first molecular analysis of MMA in Iranian patients and have identified eight novel mutations. Four novel mutations (p.D625A, p.R326G, p.V157F, p.F379L) were seen exclusively in patients from northern Iran. One novel splice site mutation (c.2125-3C>G) in MUT and two novel mutation (p.N225M and p.A99P) in the MMAA gene were associated with patients from eastern Iran. The rs184829210 SNP was recognized only in patients with the novel c.958G>A (p.A320T) mutation. This study confirms pathogenesis of deficient enzyme activity in MUT, MMAA, MMAB, and MMACHC as previous observations. These results could act as a basis for the performance of pharmacological therapies for increasing the activity of proteins derived from these mutations.

Isolation and identification of chemotherapy-enriched sphere-forming cells from a patient with gastric cancer.

Gastric cancer (GC) is the third and fifth cause of cancer-associated mortality for men and women throughout the world, respectively. Despite the use of surgery and chemotherapy for GC therapy, there are no efficient therapeutic protocols for it to date. Cancer stem cells (CSCs) due to their pivotal role in tumor initiation, growth, progression, invasion, distant metastasis, recurrence and resistance to anticancer drugs are very appealing targets for cancer therapies. Here, we isolated and identified CSCs from a chemotherapy-treated patient. Small subpopulation of dissociated cells after tissue digestion formed spheroid colonies in serum-free media under the non-adherent condition. These spheroid colonies differentiated into epithelial like cells in serum-containing medium. Few sphere-forming cells carried CD44 and CD54 markers overexpressed DLL4 that is responsible for tumor growth and angiogenesis. Subcutaneous injections of sphere-forming cells in different passages conferred tumorigenicity in nude mice. Sphere-forming cells upregulated CD44 polymorphisms CD44v3, -v6, and -v8 -10, stemness factors OCT4, SOX2, SALL4 and Cripto-1, self-renewal molecules IHh, Wnt, ß-catenin and BMI1, and epithelial mesenchymal transition (EMT) markers Twist1 and Snail1 in vitro and in vivo. Moreover, these cells similar to sphere-forming cells isolated from a chemotherapy-free patient expressed Oct-4 and ß-catenin proteins. However, the Twist1 protein was only expressed by sphere-forming cells derived from the chemotherapy-treated patient. Thus, these cells have all the characteristics of stationary and migratory CSCs, including tumorigenicity, self-renewal, pluripotency, invasion and metastasis. Taken together, targeting chemotherapy-enriched CSCs as chemo-resistance cells observed in GC patients can provide more effective therapeutic strategies compared to untreated patients.

A novel mutation in the cathepsin C (CTSC) gene in Iranian family with Papillon-Lefevre syndrome.

OBJECTIVES: In this study, we analyzed the whole exomes of CTSC gene in a family with history of PLS. MATERIALS AND METHODS: Genomic DNA was extracted from peripheral blood and genotype analysis was performed. The mutated protein sequence was used to find the best possible tertiary structure for homology modeling. The homology modeling of the novel mutation was then performed using the online Swiss-Prot server. The results were also analyzed for to verify its validity. RESULTS: The analysis of CTSC gene elucidated a novel insertion GAC. The novel mutation was proved by analyzing 50 healthy control volunteers. Modeling of the novel found mutation in CTSC gene revealed structural defects that may have caused the functional abnormalities. CONCLUSIONS: The structural analysis of the mutated protein model identifies changes in the stereo-chemical and the energy level of the mutated protein. Since this protein play a role in the activation of granule serine proteases from cytotoxic T lymphocytes, natural killer cells, mast cells, such structural defects may lead to its malfunction causing dysfunctioning of immune defense mechanisms.

Five cases of severe vesico-ureteric reflux in a family with an X-linked compatible trait.

Vesico-ureteric reflux (VUR) is one the most common inherited disorder in humans. Even though this defect is common among siblings and parents of index patients (27-40%), the mode of inheritance is not well defined. Parents and siblings (three female and two male) of a 13-year-old girl with end-stage renal failure (ESRF) due to reflux nephropathy were screened for VUR although they had not presented episodes of urinary tract infection. VUR was identified in the father (44 years old) and in all the three sisters (aged 15 years, 16 years and 18 years) while the two brothers (aged 5 years and 8 years) had normal renal ultrasonograms and cystograms. A technetium-99m di-mercapto-succinic acid ((99m)Tc-DMSA) scan demonstrated renal scars in the father and in two of the sisters with VUR. No episodes of urinary infection had been documented for any relatives. Haplotype analysis on the X-chromosome confirmed paternity. This is the first description of VUR compatible with an X-dominant trait. This mode of inheritance must be added to what is already known on familial VUR, and future studies should also consider this possibility.

Rare gross deletion in T-cell immune regulator-1 gene in Iranian family with infantile malignant osteopetrosis.

Infantile malignant osteopetrosis (arOP) is an autosomal recessive disorder. Mutations in the T-cell immune regulator 1 (TCIRG1) gene were found as the cause of arOP. We found the first Iranian patient with a rare gross deletion in this gene. The patient was a 5-year-old girl with macrocephaly, facial dysmorphism, blindness, mental retardation, hepatosplenomegaly, pancytopenia, and osteosclerotic changes in the skull and limb. Molecular analysis was performed using reverse transcriptase-polymerase chain reaction for exons 10-19 of the TCIRG1 gene followed by whole gene sequencing. She showed a 275 bp unexpected amplified segment. Sequencing revealed a gross deletion in exons 10-15 transcript region of TCIRG1 that affected codon 389 to 518. Various types of mutations in the TCIRG1 gene in arOP have been reported, however, gross deletions are reported rarely. This gross deletion is the first mutation reported among Iranian patients in this gene. This deletion is also the largest deletion of TCIRG1 gene reported to date.

Nager's acrofacial dysostosis with hypertrophic cardiomyopathy.

Nager syndrome is a rare condition associated with craniofacial malformations such as, micrognathia, zygomatic hypoplasia, external ear malformations, and preaxial limb deformities. This report features a case of Nager syndrome occurring in a one-year-old boy showing microretrognathia, thumb hypoplasia, brachydactyly, hexadactyly, and hypertrophic cardiomyopathy, characteristics not usually encountered in published cases.

A novel PHOX2A/ARIX mutation in an Iranian family with congenital fibrosis of extraocular muscles type 2 (CFEOM2).

PURPOSE: To describe the clinical features of two affected members of an Iranian family with autosomal recessive congenital fibrosis of the extraocular muscles (CFEOM2) and to report their novel mutation in the PHOX2A/ARIX gene. DESIGN: Experimental study. SETTING: Institutional practice. patient population:Six members of an Iranian family with CFEOM underwent complete ocular examinations including assessment of ocular motility, visual acuity, slit-lamp biomicroscopy, tonometry, and ophthalmoscopy. EXPERIMENTAL PROCEDURE: Mutation analysis of the PHOX2A gene was performed using polymerase chain reaction amplification of the coding exons and direct sequencing of polymerase chain reaction products. MAIN OUTCOME MEASURE: Presence or absence of mutation in PHOX2A gene in two siblings with exotropia and recessive CFEOM. Exotropia and ptosis were corrected surgically in one of the two siblings. RESULTS: The two affected siblings had bilateral ptosis and exotropia and severe limitation of all extraocular movements. One patient underwent strabismus surgery and ptosis repair. PHOX2A mutation analysis revealed a novel nonsense mutation in exon 2 (439C-->T). Both parents and the unaffected siblings were heterozygous,and the two affected siblings were homozygous for this mutation. CONCLUSIONS: The 439C-->T mutation in this family changes a glutamine to a stop codon (Q90X) at the beginning of the PHOX2A homeodomain region. This is the fourth CFEOM2 mutation in PHOX2A and the first nonsense mutation to be identified. It confirms PHOX2A as the autosomal recessive CFEOM2 disease gene and provides evidence that the phenotypic differences between PHOX2A mutations in man and mouse do not result from hypomorphic PHOX2A alleles in humans.

Two novel familial balanced translocations t(8;11)(p23;q21) and t(6;16)(q26;p12) implicated in recurrent spontaneous abortion.

Reciprocal translocations represent one of the most common structural rearrangements observed in humans. Estimates of the population frequency range from 1/673 to 1/1000. We have described two novel balanced translocations in two unrelated families who experienced Recurrent spontaneous abortions (RSA) following their separate non-consanguineous marriages. Initial cytogenetic studies were performed on cultured blood cells. High resolution GTG-banding analysis using cytovision software performed on their chromosomes revealed a novel balanced translocation t(8;11)(p23;q21) in a brother (45 years) and his sister (27 years) in one family. The second novel balanced translocation t(6;16)(q26;p12) was observed in a consanguineous couple with 4 RSA. These two families have an increased risk of having children with unbalanced karyotypes or RSA, because of incorrect chromosomal segregation during meiosis.

Gene dosage analysis of proximal spinal muscular atrophy carriers using real-time PCR.

BACKGROUND: Autosomal recessive spinal muscular atrophy is a disease resulting from homozygous absence of SMN1 gene in approximately 94% of SMA patients. To identify patients who retained a single SMN1 copy, SMN1 dosage analysis was performed by quantitative Real-time PCR using SYBR green dye. SMN1 dosage analysis results were utilized to identify carriers before offering prenatal diagnosis. METHOD: Carrier testing was performed for 150 individuals. Copy number of the SMN1 gene was determined by the comparative threshold cycle (Ct) method and human serum albumin gene was used as a reference. RESULT: Analysis of 150 DNA samples with quantitative PCR determined the number of SMN1 gene copies. Of these, 50 (33.33%) cases had one SMN1 gene copy, 87 (58%) had two copies and 13 (8.66%) did not have any copies of SMN1. The homozygous SMN1 deletion ratio was 0.00 and deletion of one copy of SMN1 gene ratio ranged from 0.3 to 0.58. CONCLUSION: This report demonstrates modification of risk estimation for the diagnosis and detection of SMA carriers by accurate determination of SMN1 copy number. SMN1 copy number analysis is an important parameter for identification of couples at risk of having children affected with SMA. It also reduces unwarranted prenatal diagnosis for SMA. Furthermore, the dosage analysis might be useful for the counseling of clinically suspected SMA patients with negative diagnostic SMA tests.

Evaluation of polymerase chain reaction for diagnosis of "tuberculous pleurisy".

BACKGROUND: Differential diagnosis between tuberculous pleurisy (TBP) and non- tuberculosis pleural effusion represents a critically important clinical problem. In recent years, several noninvasive methods have been found for diagnosis of tuberculous pleurisy. This study aimed to evaluate the value of detection of the genome of Mycobacterium tuberculosis (MTB) by polymerase chain reaction (PCR) method for the diagnosis of tuberculous pleurisy and compare the results with those of conventional methods. MATERIALS AND METHODS: In this cross-sectional study, we studied 62 patients (42 men and 20 women) with pleural effusion in Ghaem Hospital, affiliated to Mashhad University of Medical Sciences from January 2006 to June 2007. RESULTS: A total of 20 patients had tuberculous pleurisy (45.4%), 15 patients had malignant pleural effusion (34%), 3 patients had pleural effusion with various "non-tuberculosis non-malignant" etiologies (6.8%) and 6 patients had transudative pleural effusion (13.6). The sensitivity, specificity, positive predictive value and negative predictive value of PCR in tuberculous pleurisy were 85%, 100%, 100% and 88.8%, respectively. CONCLUSION: The value of PCR test and pleural biopsy was similar in the diagnosis of TBP. However, PCR detected MTB in pleural effusion when conventional pleural biopsy failed to do so.