Chromosomal analysis of couples with repeated spontaneous abortions in northeastern iran.

BACKGROUND: Cytogenetic study of reproductive wastage is an important aspect in determining the genetic background of early embryogenesis. Approximately 15 to 20% of all pregnancies in humans are terminated as recurrent spontaneous abortions (RSAs). The aim of this study was to detect chromosome abnormalities in couples with RSAs and to compare our results with those reported previously. MATERIALS AND METHODS: In this retrospective study, the pattern of chromosomal aberrations was evaluated during a six-year period from 2005 to 2011. The population under study was 728 couples who attended genetic counseling services for their RSAs at Pardis Clinical and Genetics Laboratory, Mashhad, Iran. RESULTS: In this study, about 11.7% of couples were carriers of chromosomal aberrations. The majority of abnormalities were found in couples with history of abortion, without stillbirth or livebirth. Balanced reciprocal translocations, Robertsonian translocations, inversions and sex chromosome aneuploidy were seen in these cases. Balanced reciprocal translocations were the most frequent chromosomal anomalies (62.7%) detected in current study. CONCLUSION: These findings suggest that chromosomal abnormalities can be one of the important causes of RSAs. In addition, cytogenetic study of families who experienced RSAs may prevent unnecessary treatment if RSA are caused by chromosomal abnormalities. The results of cytogenetic studies of RSA cases will provide a standard protocol for the genetic counselors in order to follow up and to help these families.

Inherited genetic markers for thrombophilia in northeastern Iran (a clinical-based report).

BACKGROUND: Thrombophilia is a main predisposition to thrombosis due to a procoagulant state. Several point mutations play key roles in blood-clotting disorders, which are grouped under the term thrombophilia. These thrombophilic mutations are methylenetetrahydrofolate reductase (MTHFR, C677T, and A1298C), factor V Leiden (G1691A), prothrombin gene mutation (factor II, G20210A), and plasminogen activator inhibitor (PAI). In the present study, we assessed the prevalence of the above thrombophilia markers in patients with recurrent pregnancy loss or first and second trimester abortions, infertility, and failed in vitro fertilization (IVF). METHODS: This study was conducted among 457 cases those were referred to detect the inherited genetic markers for thrombophilia. Markers for MTHFR, Factor II, and Factor V were assessed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP), and PAI was assessed by Amplification Refractory Mutation System (ARMS-PCR). RESULTS: Two hundred sixty cases (56.89%) were diagnosed as having at least one thrombophilia marker, whereas 197 cases (43.11%) had no thrombophilia markers and were normal. CONCLUSION: According to the current study, the pattern of abnormal genetic markers for thrombophilia in northeastern Iran demonstrates the importance of genetic evaluations in patients who show clinical abnormalities with recurrent spontaneous abortion (RSA) or other serious obstetric complications.

Two novel mutations in CYP11B1 and modeling the consequent alterations of the translated protein in classic congenital adrenal hyperplasia patients.

Mutations in the 11ß-hydroxylase (CYP11B1) gene are the second leading cause of congenital adrenal hyperplasia (CAH), an autosomal recessive disorder characterized by adrenal insufficiency, virilization of female external genitalia, and hypertension with or without hypokalemic alkalosis. Molecular analysis of CYP11B1 gene in CAH patients with 11ß-hydroxylase deficiency was performed in this study. Cycle sequencing of 9 exons in CYP11B1 was performed in 5 unrelated families with 11ß-hydroxylase deficient children. Three-dimensional models for the normal and mutant proteins and their affinity to their known substrates were examined. Analysis of the CYP11B1 gene revealed two novel mutations, a small insertion in exon 7 (InsAG393) and a small deletion in exon 2 (DelG766), and three previously known missense mutations (T318M, Q356X, and R427H). According to docking results, the affinity of the protein to its substrates is highly reduced by these novel mutations. DelG766 has more negative impact on the protein in comparison to InsAG393. The novel mutations, InsAG393 and DelG766, change the folding of the protein and disrupt the enzyme's active site as it was measured in the protein modeling and substrate binding analysis. Molecular modeling and sequence conservation were predictive of clinical severity of the disease and correlated with the clinical diagnosis of the patients.

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.