RESUMO
The origin of a de novo metacentric small marker chromosome found in a cytogenetic study in amniotic fluid was determined by fluorescence in situ hybridization (FISH) using chromosome specific probes. It was identified as an isochromosome 18p. We want to emphasize that when an extra chromosome is found in prenatal diagnosis and it cannot be identified by conventional cytogenetics banding, FISH should be applied in order to give real risks for fetal anomalies and an accurate genetic counselling.
Assuntos
Cromossomos Humanos Par 18 , Aconselhamento Genético , Isocromossomos , Diagnóstico Pré-Natal/métodos , Líquido Amniótico/fisiologia , Pré-Escolar , Fibroblastos/fisiologia , Marcadores Genéticos , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Linfócitos/fisiologia , MasculinoRESUMO
A girl aged 4 years 3 months with sporadic unilateral Wilms' tumor associated with Wiedemann-Beckwith syndrome, but without aniridia, was found to have a t(X;20) in the tumor cells. Karyotypes of peripheral blood of the patient and her parents were normal. This translocation was confined to the tumor and not been previously reported either in nephroblastoma or any other neoplastic processes. Although there is no microscopic deletion on chromosome 11 and catalase activity was not decreased, we cannot rule out the possibility of a point mutation or a submicroscopic deletion.
Assuntos
Síndrome de Beckwith-Wiedemann/genética , Cromossomos Humanos Par 20 , Neoplasias Renais/genética , Translocação Genética , Tumor de Wilms/genética , Cromossomo X , Pré-Escolar , Feminino , Humanos , CariotipagemRESUMO
Five children, three males and two females were found to have a short arm deletion of chromosome 18. Four of them display some of the typical features of this syndrome: microcephaly, round face, hypertelorism, broad-based nose, "carp-mouth", microrethrognathia, pterygium colli, dysplastic and low set ears, clinodactily, failure to grow, muscular hypotony and mental retardation. Different hypotheses are discussed in order to explain the variable phenotypical expression of the 18 p-syndrome.
Assuntos
Anormalidades Múltiplas/genética , Aberrações Cromossômicas/genética , Deleção Cromossômica , Cromossomos Humanos Par 18/ultraestrutura , Deficiência Intelectual/genética , Agamaglobulinemia/genética , Criança , Pré-Escolar , Aberrações Cromossômicas/patologia , Transtornos Cromossômicos , Face/anormalidades , Feminino , Transtornos do Crescimento/genética , Humanos , Deficiência de IgA , Lactente , Recém-Nascido , Masculino , Linhagem , SíndromeRESUMO
This paper concerns the case of an anencephalus male fetus with partial trisomy 20p product of a maternal translocation 46,XX, t(15;20) (p11.2;p12), ascertained by prenatal diagnosis. A cytogenetic review of previous cases is presented. Several hypotheses are discussed in order to explain the recurrent abortions of the mother and the aetiology of anencephaly in this last pregnancy.
Assuntos
Anencefalia/genética , Cromossomos Humanos Par 20 , Trissomia , Aborto Habitual/genética , Anencefalia/diagnóstico , Cromossomos Humanos Par 15 , Feminino , Humanos , Linhagem , Gravidez , Diagnóstico Pré-Natal , Translocação GenéticaRESUMO
Authors present a new case with partial trisomy for long arms of chromosome 18(q12-qter) resulting from a balanced translocation t(4;18) on her mother. Comparing clinical features of our patient with that of other reported cases with the same trisomic segment, we can deduce that most important characteristics on this syndrome are: psychomotor and grow retardation, congenital heart disease, dolicocephaly, low set and malformed ears, micrognathia, short neck with redundant skin and a longer survival than in total trisomy 18.
