RESUMEN
OBJECTIVES: To use the PCR-RFLP-based linkage analysis for non-invasive prenatal diagnosis of ß-thalassemia. BACKGROUNDS: Thalassemia is a prevalent genetic disorder occurring throughout the world. Cell-free fetal DNA (cffDNA) in the maternal plasma during pregnancy has been used to develop non-invasive prenatal screening and diagnostic tests. METHODS: PCR-RFLP for six SNPs in the ß-globin gene was executed on paternal and maternal DNA as well as DNA extracted from CVS of the fetuses in seven ß-thalassemic families. Based on the results, two families in which the paternal inherited SNPs in specific loci were different from the maternal one were selected and PCR-RFLP was performed on cffDNA extracted from the maternal plasma. RESULTS: Paternal SNPs in cffDNA were distinguished and the inheritance of paternally normal or mutant ß globin allele was predicted by linkage analysis. CONCLUSION: The use of PCR-RFLP on cffDNA as a simple and inexpensive method was capable to provide similar results achieved by studying CVS of the fetuses. However, there is a limiting factor in this approach, namely that there is the little amount of cffDNA in maternal plasma. The PCR yield was improved either by adding BSA to PCR reaction or increasing the PCR cycles (Tab. 2, Fig. 2, Ref. 18).
Asunto(s)
ADN/sangre , Ligamiento Genético , Familia de Multigenes , Embarazo/sangre , Diagnóstico Prenatal/métodos , Globinas beta/genética , Talasemia beta/diagnóstico , Sistema Libre de Células , Femenino , Humanos , Polimorfismo de Nucleótido SimpleRESUMEN
Type 1 Diabetes mellitus (T1D) is an autoimmune and multifactorial disease. HLA-DRB1 and DQB1 loci have the strongest association with T1D. This study aimed at investigating (i) susceptibility or protection of alleles, genotypes and haplotypes of HLA-DRB1 and DQB1 loci; and (ii) highly polymorphic amino acid residues of HLA-DRß1 and DQß1 in 105 Iranian T1D patients and 100 controls. The results indicated that DRB1*04:01, 03:01, DQB1*03:02, 02:01 alleles, DRB1*03:01/04:01, 03:01/13:03, DQB1*02:01/03:02 genotypes, DRB1*04:01-DQB1*03:02, DRB1*03:01-DQB1*02:01, DRB1*07:01-DQB1*03:03 haplotypes had positive association with T1D. In contrast, HLA-DRB1*15:01, 13:01, DQB1*03:01, 06:01 alleles, DRB1*11:01/15:01, DQB1*03:01/06:01, 03:01/05:01 genotypes and DRB1*15:01-DQB1*06:01, DRB1*11:01-DQB1*03:01 haplotypes had negative association with T1D. Analysis of amino acid sequence of HLA-DRß1 and DQß1 revealed that DRß1(Lys71+) and DQß1(Asp57-) were significantly more frequent in patients than in controls and had a positive effect in the development of T1D. Haplotype analysis demonstrated that HLA-DRB1(Lys71+) allele provided major susceptibility for T1D, and DQß1(Asp57-) had an additive effect. We designed an allele-specific primer to develop an easy, quick and cost-benefit method to detect the DRß1(Lys71+) . This method can identify all 114 DRB1 alleles encoding DRß1(Lys71+) by three PCR reactions. The PcPPV and PcNPV were also calculated to determine the impact of HLA genotype testing at amino acid positions. It showed that the DRß1(Lys71+/+) genotype carrier had 1% absolute risk of developing T1D.
Asunto(s)
Diabetes Mellitus Tipo 1/genética , Cadenas beta de HLA-DQ/genética , Cadenas HLA-DRB1/genética , Polimorfismo Genético , Adolescente , Alelos , Estudios de Casos y Controles , Niño , Preescolar , Diabetes Mellitus Tipo 1/epidemiología , Diabetes Mellitus Tipo 1/metabolismo , Frecuencia de los Genes , Estudios de Asociación Genética , Sitios Genéticos , Predisposición Genética a la Enfermedad , Técnicas de Genotipaje/métodos , Haplotipos , Humanos , Irán/epidemiología , Reacción en Cadena de la Polimerasa/métodos , Reproducibilidad de los Resultados , Factores de Riesgo , Análisis de Secuencia de Proteína , Población Blanca/genéticaRESUMEN
Chromosomal abnormalities and ZAP70 expression profile are two major independent prognostic markers in B-cell chronic lymphocytic leukemia. We investigated a possible correlation between these two markers. ZAP70 expression using real-time RT-PCR was examined in 20 B-cell chronic lymphocytic leukemia patients with del13q14, 13 patients with del11q22, 15 patients with trisomy 12, and 16 patients with no detected chromosomal abnormalities. Molecular analysis revealed that ZAP70 expression in the del13q subgroup was the same as in the control group, while it increased 2.78-fold in the del11q subgroup and 2.95-fold in the trisomy 12 subgroup, compared to the 15 cases in the control group. Comparison of the mean and standard deviation of the ZAP70 expression profile within the subgroups showed it to be highly variable among the individuals of the del11q and trisomy 12 subgroups, versus tight clustering for the del13q subgroup. Therefore, there is a correlation between del13q aberration, which has good prognosis with normal levels of ZAP70 expression. Due to a high degree of variation, no conformity is seen for del11q and trisomy 12 subgroups, making this grouping poor for prognostic discrimination. As a result, neither of these markers can serve as sole discriminators to determine the course of the disease; the use of both markers improves prognostic assessment.
Asunto(s)
ADP-Ribosil Ciclasa 1/biosíntesis , Regulación Leucémica de la Expresión Génica , Leucemia Linfocítica Crónica de Células B/metabolismo , Glicoproteínas de Membrana/biosíntesis , Proteínas de Neoplasias/biosíntesis , ARN Mensajero/biosíntesis , ARN Neoplásico/biosíntesis , Proteína Tirosina Quinasa ZAP-70/biosíntesis , ADP-Ribosil Ciclasa 1/genética , Deleción Cromosómica , Cromosomas Humanos/genética , Femenino , Humanos , Irán , Leucemia Linfocítica Crónica de Células B/diagnóstico , Leucemia Linfocítica Crónica de Células B/genética , Masculino , Glicoproteínas de Membrana/genética , Proteínas de Neoplasias/genética , Pronóstico , ARN Mensajero/genética , ARN Neoplásico/genética , Trisomía , Proteína Tirosina Quinasa ZAP-70/genéticaRESUMEN
Identification of molecular basis of phenylketonuria (PKU) in Iran has been accomplished through the analysis of 248 unrelated chromosomes from 124 Iranian classic PKU subjects. Phenylalanine hydroxylase (PAH) gene mutations were analyzed through a combined approach in which p.S67P, p.R252W, p.R261Q, p.R261X, p.L333F, IVS10-11G>A, IVS11+1G>C, p.L364del, p.R408Q and p.R408W mutations were first screened by PCR of PAH gene exons 3, 7, 10, 11 and 12, followed by digestion with the appropriate digestion enzymes. Subsequently SSCP analysis for exons 2, 6, 7 and 11 of the PAH gene and finally, sequencing of 13 PAH gene exons have been used to study uncharacterized PKU chromosomes. 26 different mutations were found. The predominant mutation in this population sample was IVS10-11G>A, with a frequency of 24.6%. Nine mutations (IVS10-11G>A, p.R261Q, p.P281L, IVS11+1G>C, p.K363>NFS, p.R243X, IVS2+5G>C, p.R261X and p.R252W) represent almost 84% of all PKU chromosomes studied. IVS10-11G>A mutation is the major PKU-causing mutation throughout the Mediterranean region. The finding of the high prevalence of this mutation in Iranian population is consistent with the historical and geographical links between Iranian and Mediterranean populations.
Asunto(s)
Fenilalanina Hidroxilasa/genética , Fenilcetonurias/genética , Secuencia de Bases , Heterocigoto , Homocigoto , Humanos , Irán , Mutación , Fenilcetonurias/epidemiología , Polimorfismo GenéticoRESUMEN
Rett syndrome is a rare genetic X-linked dominant disorder. This syndrome is the most frequent cause of mental retardation in girls. In the classical form of the disease, the presenting signs and the course of development are characteristic. However clinical diagnosis can be very difficult when the expression is not in the classical form. Mutations in MeCP2 are responsible for 80% of cases. When MeCP2 mutation is found in an index case, genetic counseling is similar to that in other X-linked dominant genetic diseases. However, mutations in this gene can cause a spectrum of atypical forms. On the other hand, other genetic conditions like translocations, sex chromosome numerical anomalies, and mutations in other genes can complicate genetic counseling in this syndrome. We present the first case of molecular diagnosis of Rett syndrome in Iran and discuss the recent developments in its genetic counseling.
RESUMEN
Prometaphase and metaphase chromosome analyses performed on 70 consecutive men with primary infertility (for a period of at least 2 years) revealed 8 (11.42%) men with some kind of chromosomal abnormality. The highest frequency of abnormal karyotypes (10%) was found among patients with azpospennia and the most frequent anomaly was 47, XXY chromosomal constitution, found in 6 (8.57%) patients. All the chromosomal aberrations found in this study was sex chromosomal type and we did not find any autosomal aberration. All patients with numerical chromosomal anomalies had azoospermia. The incidence of structural aberration in our study was 1.42%. Fifteen patients had different chromosomal variants (21.38%). We suggest that men with azoospermia should be considered for cytogenetic investigation and we report that "variants of the Y chromosome" have no influence on the sperm count (million/ml) and fertility of men.
Asunto(s)
Aberraciones Cromosómicas , Infertilidad Masculina/genética , Adulto , Cromosomas Humanos X/genética , Cromosomas Humanos Y/genética , Humanos , Cariotipificación , Masculino , Persona de Mediana Edad , Oligospermia/genética , Aberraciones Cromosómicas Sexuales , Recuento de Espermatozoides , TrisomíaRESUMEN
Prometaphase and metaphase chromosome analyses performed on 70 consecutive men with primary infertility (for a period of at least 2 years) revealed 8 (11.42%) men with some kind of chromosomal abnormality. The highest frequency of abnormal karyotypes (10%) was found among patients with azoospermia and the most frequent anomaly was 47, XXY chromosomal constitution, found in 6 (8.57%) patients. All the chromosomal aberrations found in this study, was sex chromosomal type and we did not find any autosomal aberration. All patients with numerical chromosomal anomalies had azoospermia. The incidence of structural aberration in our study was 1.42%. 15 patients had different chromosomal variants (21.38%). We suggest that men with azoospermia should be considered for cytogenetic investigation and we report that "variants of the Y chromosome" have no influence on the sperm count (Million/ml) and fertility of men.
Asunto(s)
Aberraciones Cromosómicas , Infertilidad Masculina/genética , Adulto , Humanos , Cariotipificación , Masculino , Persona de Mediana Edad , Oligospermia/genética , Aberraciones Cromosómicas Sexuales , Recuento de Espermatozoides , Trisomía , Cromosoma X/genética , Cromosoma Y/genéticaRESUMEN
The base sequence of cDNA encoding the complete human liver cysteine dioxygenase type I (CDO-I; EC 1.13.11.20) message, and the derived amino-acid sequence are reported. CDO-I is encoded on a single mRNA species (approx. 1.5 kb). Human CDO-I clones were identified by screening a liver cDNA library, and inserts were isolated and sequenced. In addition, human liver total RNA was reverse-transcribed and CDO-I cDNA amplified by PCR using a modified poly-T primer and specific CDO-I primers to give a second source of sequencing template. The CDO-I message encodes a 200 amino-acid residue protein, the sequence of which has greater than 90% homology with the equivalent rat enzyme. The message was not expressed in a human hepatoma cell line (Hep G2).
Asunto(s)
Dioxigenasas , Oxigenasas/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Northern Blotting , Cisteína-Dioxigenasa , Sondas de ADN , ADN Complementario , Biblioteca de Genes , Humanos , Hígado/enzimología , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa/métodos , ARN Mensajero/genética , ADN Polimerasa Dirigida por ARN , Ratas , Homología de Secuencia de Aminoácido , Células Tumorales CultivadasRESUMEN
A portion of the human X-chromosome (> 5 kb) encoding the translated portion of the thyroxine-binding globulin (TBG) gene was sequenced. The primary templates for sequencing were isolated from a human X-chromosome library (two positive plaques from 400,000 screened initially with a TBG cDNA probe) or were produced by PCR amplification using leucocyte genomic DNA as the amplification template. Potential hormone response elements (HREs) were identified at either end of the gene. These HREs have sequences based on the consensus half-site of thyroid hormone response elements, although it is unclear whether the structures are functional HREs. Other potential regulatory elements also were identified towards the 3' end of the gene.
Asunto(s)
Hominidae/genética , Proteínas de Unión a Tiroxina/genética , Cromosoma X , Animales , Secuencia de Bases , Secuencia de Consenso , Sondas de ADN , Exones , Humanos , Datos de Secuencia Molecular , Oligonucleótidos Antisentido , Reacción en Cadena de la Polimerasa , Biosíntesis de Proteínas , Mapeo Restrictivo , Homología de Secuencia de Ácido Nucleico , Moldes GenéticosRESUMEN
Amplification and sequencing of the four transthyretin (TTR) exons of a subject with a variant TTR with four-fold increased affinity for thyroxine revealed a heterozygous G to A point mutation at base 7 of exon 2. This results in a serine for glycine change at residue 6 of the mature TTR monomer. No other mutations were found in any exon. Amplification and MspI digestion of TTR exon 2 from the leucocyte DNA of eight members of the subject's family revealed that all but one member were also heterozygous for [Ser6]-TTR.
Asunto(s)
Exones/fisiología , Prealbúmina/genética , Tiroxina/metabolismo , ADN/análisis , Femenino , Humanos , Masculino , Mutación/fisiología , Linaje , Reacción en Cadena de la Polimerasa , Prealbúmina/metabolismoRESUMEN
The human thyroxine-binding prealbumin (TBPA) gene was examined for restriction fragment length polymorphism (RFLP) in normal subjects and a subject with euthyroid hyperthyroxinaemia, due to increased thyroxine binding by TBPA, using 16 restriction enzymes. Only Taq I and Msp I were shown to detect RFLPs. In a male of the normal population and one of his daughters, an additional Taq I site was found in the 3'-flanking region of the TBPA gene. The RFLP in a subject with euthyroid hyperthyroxinaemia was due to the deletion of a MspI site. All three subjects with RFLPs were heterozygous.
Asunto(s)
Hipertiroxinemia/genética , Polimorfismo de Longitud del Fragmento de Restricción , Prealbúmina/genética , Proteínas de Unión a Tiroxina/genética , Adulto , Deleción Cromosómica , Computadores , Electroforesis en Gel de Agar , Exones/genética , Femenino , Genes/genética , Humanos , Masculino , Persona de Mediana EdadRESUMEN
From some 500 members of Christian communities in Iran (Armenians and Assyrians from six localities), blood specimens were obtained and examined for a number of blood group, red cell enzyme, and serum protein systems. The results indicate the relatively closed nature of the Christian community as a whole but that moderate differentiation has already occurred among the local groups. One factor in this diversification process that can be distinguished is the effect of urbanization in Tehran, but otherwise it seems to be largely random.
Asunto(s)
Cristianismo , Variación Genética , Genética de Población , Antígenos de Grupos Sanguíneos/genética , Proteínas Sanguíneas/genética , Eritrocitos/enzimología , Frecuencia de los Genes , Marcadores Genéticos , Humanos , IránRESUMEN
Frequencies of 10 polymorphic systems were investigated in two ethnic groups (Turkoman and Bandari) living near the northern and southern borders of Iran, respectively. A further 6 blood group and enzyme systems were also investigated in Bandari alone and 4 in Turkoman alone. 4 out of 10 commonly studied systems (ABO, Rh, AP and Tf) showed significant frequency differences between these populations. Wright's FIS indicates moderate isolation of these groups, and the gene frequency differences are therefore interpreted as indicating the differing origins of these populations.