RESUMEN
A genetic perspective of human history in Europe was derived from 22 binary markers of the nonrecombining Y chromosome (NRY). Ten lineages account for >95% of the 1007 European Y chromosomes studied. Geographic distribution and age estimates of alleles are compatible with two Paleolithic and one Neolithic migratory episode that have contributed to the modern European gene pool. A significant correlation between the NRY haplotype data and principal components based on 95 protein markers was observed, indicating the effectiveness of NRY binary polymorphisms in the characterization of human population composition and history.
Asunto(s)
Pool de Genes , Genética de Población , Cromosoma Y , Alelos , Antropología Física , Clima , ADN Mitocondrial/genética , Emigración e Inmigración , Europa (Continente) , Femenino , Marcadores Genéticos , Historia Antigua , Humanos , Masculino , Medio OrienteRESUMEN
Despite the increasing number of reports of families with hearing impairment and mitochondrial DNA (mtDNA) mutations, the frequency of these mutations as causes of non-syndromic sensorineural hearing impairment (NSSHI) remains unknown. Mutations such as A1555G, A7445G and 7472insC have been found in several unrelated families implying they are more frequent than initially thought. We describe a family with NSSHI due to the presence of the homoplasmic mtDNA A7445G mutation in the tRNASer(UCN) gene. This is the fourth such family described with this mutation, all of different genetic backgrounds. Our study also demonstrates the difficulties sometimes encountered in establishing mitochondrial inheritance of hearing impairment in some families.
Asunto(s)
ADN Mitocondrial/genética , Sordera/genética , ADN/química , ADN/genética , Análisis Mutacional de ADN , ADN Mitocondrial/química , Sordera/patología , Salud de la Familia , Femenino , Humanos , Masculino , Linaje , Mutación PuntualRESUMEN
The contribution of genetic factors to spontaneous level of the sister chromatid exchanges (SCE) has been determined on the basis of the twin method of study. A close relation is shown to exist between the SCE tests in the group of the monozygotic twins which is a result of the common genotype. The SCE test with late BUdR introduction is under rigid genetic control.
Asunto(s)
Variación Genética , Intercambio de Cromátides Hermanas , Adolescente , Bromodesoxiuridina/farmacología , Células Cultivadas , Contaminantes Ambientales/efectos adversos , Variación Genética/efectos de los fármacos , Genotipo , Humanos , Matemática , Intercambio de Cromátides Hermanas/efectos de los fármacos , Gemelos Dicigóticos , Gemelos MonocigóticosRESUMEN
Hypothesis about cytoplasmic heredity and the influence of mitochondrial DNA mutations on the pathogenesis of 21 trisomy has been suggested. It explains the association of increased risk of trisomy with the maternal age, malignant diseases, autoimmune processes, other pathologies and with the origin of paternal 21 chromosome.
Asunto(s)
ADN Mitocondrial/genética , Síndrome de Down/etiología , Cromosomas Humanos Par 21/genética , Síndrome de Down/genética , Femenino , Humanos , Masculino , MutaciónRESUMEN
The high level of free radicals and antioxidant protection disbalancing cause the chromosome nondisjunction in meiosis, appearance of trisomy 21 and fetuses with Down's syndrome, age-dependent pathology, of parent's mosaic clone, clinical manifestations of the syndrome, diseases in relatives, recurrent cases of trisomy 21. The comparative analysis of clinical traits of Down's syndrome and pathological changes in families with after-effects of radiation exposure was carried out. The factors causing an increase in the level of free radicals were considered.
Asunto(s)
Síndrome de Down/etiología , Radicales Libres/metabolismo , Aborto Espontáneo/etiología , Aborto Espontáneo/genética , Aborto Espontáneo/metabolismo , Adolescente , Adulto , Envejecimiento/genética , Envejecimiento/metabolismo , Antioxidantes/metabolismo , Niño , Síndrome de Down/diagnóstico , Síndrome de Down/genética , Síndrome de Down/metabolismo , Femenino , Humanos , Masculino , No Disyunción Genética , Fenotipo , Embarazo , Traumatismos por Radiación/diagnóstico , Traumatismos por Radiación/genética , Traumatismos por Radiación/metabolismoRESUMEN
Age-dependent distribution of Down syndrome frequency in the light of free-radical theory of aging was carried out in this work. The frequency of Down syndrome had been analysed during the period of 1990-1995. The investigation of radical process intensity was performed in the group of women of child-bearing age by the chemoluminescence method. It has been demonstrated that the age of a woman is one of the main reasons both of Down syndrome frequency increase and free radical accumulation. The obtained analogy between age-dependent distribution of Down syndrome frequency and age-dependent accumulation of free radicals is one more argument for the role of free radicals in the pathogenesis of Down syndrome.
Asunto(s)
Síndrome de Down/epidemiología , Radicales Libres/sangre , Edad Materna , Adolescente , Adulto , Envejecimiento/sangre , Síndrome de Down/sangre , Síndrome de Down/etiología , Femenino , Humanos , Incidencia , Mediciones Luminiscentes , Persona de Mediana Edad , Embarazo , Ucrania/epidemiologíaRESUMEN
The association of the levels of alpha-fetoprotein and chorionic gonadotropin with congenital developmental defects and chromosomal abnormalities of fetus was studied. The correlation of elevated level of alpha-fetoprotein with defects of neuraxis, kidney and abdominal wall of fetus was shown. These data are used for screening of women with a high risk for Down's syndrome and other chromosomal abnormalities.
Asunto(s)
Gonadotropina Coriónica/sangre , Anomalías Congénitas/diagnóstico , Anomalías Congénitas/prevención & control , Enfermedades Fetales/diagnóstico , Enfermedades Fetales/prevención & control , Tamizaje Masivo/métodos , Diagnóstico Prenatal/métodos , alfa-Fetoproteínas/análisis , Adolescente , Adulto , Femenino , Humanos , Embarazo , Primer Trimestre del Embarazo , Segundo Trimestre del Embarazo , Diagnóstico Prenatal/estadística & datos numéricos , UcraniaRESUMEN
While studying the pathogenetic mechanisms of Down syndrome, the imbalance of oxidant-antioxidant system in donors of extrachromosome 21 was detected. This fact was a basis for screening of new prenatal biochemical markers of Down syndrome. The ratio of free radical processes intensity and SOD activity was found as most informative index reflecting the state of oxidant-antioxidant system. It was proposed as additional criterion for the formation of high risk groups to increase the efficiency of prenatal diagnostics of Down syndrome.
Asunto(s)
Antioxidantes/metabolismo , Pruebas Genéticas/métodos , Oxidantes/sangre , Adolescente , Adulto , Biomarcadores/sangre , Cromosomas Humanos Par 21/genética , Síndrome de Down/sangre , Síndrome de Down/diagnóstico , Síndrome de Down/etiología , Síndrome de Down/genética , Eritrocitos/enzimología , Femenino , Radicales Libres/sangre , Humanos , Persona de Mediana Edad , Embarazo , Diagnóstico Prenatal/métodos , Diagnóstico Prenatal/estadística & datos numéricos , Factores de RiesgoRESUMEN
The results of the formation of women risk groups for invasive methods of prenatal diagnosis and cytogenetic investigations of amniotic fluid are presented. It was shown that the efficiency of prenatal diagnosis was increased due to the complex use of ultrasonography, screening for alpha-fetoprotein and chorionic gonadotropin, and invasive methods of prenatal diagnosis.
Asunto(s)
Amniocentesis , Adulto , Líquido Amniótico/citología , Técnicas de Cultivo de Célula/métodos , Células Cultivadas , Aberraciones Cromosómicas/diagnóstico , Trastornos de los Cromosomas , Femenino , Humanos , Edad Materna , Embarazo , Segundo Trimestre del Embarazo , Factores de RiesgoRESUMEN
The reasons for false-positive results of Down syndrome screening have been analysed. It has been found that the family pericentric inversions of chromosome 9 in fetus are accompanied by AFP and HCG changes equal to Down syndrome pregnancies. The average marker's levels in cases of per inv (9) were: AFp-0.51 MoM, HCG-3.71 MoM. The dynamics of markers in amniotic fluid has been studied. Clinical significance of per inv (9) in medicogenetic consultation were discussed.
Asunto(s)
Aberraciones Cromosómicas/sangre , Líquido Amniótico/química , Biomarcadores/sangre , Gonadotropina Coriónica Humana de Subunidad beta/análisis , Aberraciones Cromosómicas/genética , Trastornos de los Cromosomas , Inversión Cromosómica , Cromosomas Humanos Par 9/genética , Femenino , Humanos , Cariotipificación , Embarazo , Segundo Trimestre del Embarazo , Ucrania , alfa-Fetoproteínas/análisisRESUMEN
The role of maternal alpha-fetoprotein and chorionic gonadotprin screening in complex prenatal diagnosis of Down syndrome had been studied. The average markers' values in cases of fetus trisomy 21 were 0.67 MoM (AFP) and 2.68 MoM (HGG). The correlative dependence between the markers' levels in trisomy 21 and the date of testing have been found. The high efficiency of differentiative approach to invasive investigations in the older age group of pregnant (above 35 years old) on the basis of AFP and HGG screening has been established.
Asunto(s)
Gonadotropina Coriónica/sangre , Síndrome de Down/diagnóstico , Enfermedades Fetales/diagnóstico , Diagnóstico Prenatal/métodos , alfa-Fetoproteínas/análisis , Adulto , Amniocentesis , Biomarcadores/sangre , Femenino , Humanos , Edad Materna , Embarazo , Primer Trimestre del Embarazo , Segundo Trimestre del Embarazo , Factores de RiesgoAsunto(s)
Pruebas Genéticas , Diagnóstico Prenatal , Atención a la Salud , Asesoramiento Genético , Genética Médica/educación , Genética Médica/legislación & jurisprudencia , Genética Médica/tendencias , Servicios de Salud , Accesibilidad a los Servicios de Salud , Humanos , Mortalidad Infantil , Recién Nacido , Tamizaje Neonatal , Evaluación de Resultado en la Atención de Salud , Satisfacción del Paciente , Linaje , UcraniaRESUMEN
The frequently observed familial aggregation of Down syndrome (DS) 47,+21 and other aneuploidies and the phenomenon of double aneuploidy involving DS cannot be accounted for by chance alone. To clarify possible aetiological factors, pedigrees from all 7 affected families with repeated marriages referred to two regional genetics centres were examined. In each case the recurrence of aneuploidy was on the mother's side (p<0.01). Such a pattern suggests cytoplasmic inheritance of a risk factor. The hypothesis that mitochondrial DNA mutations have a role in the aetiology of DS is supported by other observations as well as by theoretical considerations.
Asunto(s)
ADN Mitocondrial , Síndrome de Down/genética , Predisposición Genética a la Enfermedad , Impresión Genómica , Humanos , Matrimonio , Edad Materna , Mutación , LinajeRESUMEN
A multicentre study was carried out to determine the frequency and clinical consequences of extremely high maternal serum pregnancy-associated plasma protein (PAPP)-A. There was a total of 79 pregnancies with PAPP-A exceeding 5.0 multiples of the gestation-specific median in a series of 46 776 pregnancies tested (0.2%) at the 7 collaborating centres. Five pregnancies were lost to follow-up, one miscarried and one with Noonan's syndrome was terminated. Of the remaining 72 that ended in a live birth, one infant had gastroschisis and five pregnancies had obstetric complications: pre-eclampsia, pregnancy-induced hypertension, gestational diabetes and two with growth retardation. Among women with high PAPP-A and no complications or adverse outcomes, there was no evidence of a substantial change in the levels of other Down syndrome markers or the extent of nuchal translucency. Three analytical methods were used to assay PAPP-A and yielded different frequencies of extremely high levels (0.05%, 0.4% and 0.6%) possibly owing to cross-reaction with another substance. We conclude that women with high PAPP-A can be reassured that there is no reason to suppose that the outcome of pregnancy will differ from those with normal levels, provided other markers are normal. If, as more centres move their Down syndrome screening practice to the first trimester, additional cases emerge with Noonan's syndrome or gastroschisis and raised PAPP-A, this advice will need to be modified.