Discordant prenatal phenotype and karyotype of monozygotic twins characterized by the unequal distribution of two cell lines investigated by different methods: a review.

We present the case of a monozygotic twin pregnancy discordant for phenotype and karyotype. A chorionic villus sample was performed at the 11th week of gestation in a primigravida because of cystic hygroma detected by ultrasound in one twin of a monochorionic, biamniotic pregnancy. Rapid testing by means of quantitative fluorescence polymerase chain reaction and conventional karyotyping, obtained by both short- and long-term culture, revealed a homogeneous monosomy X (45,X). Amniocentesis was performed separately for both twins before termination and showed an homogeneous monosomy X in one sample and a 46,X,del(X)(p11.1) karyotype in the other one. Postmortem fetal tissues culture confirmed the discordant karyotype between the two embryos. Placental samples obtained after termination revealed the cell line which was not detected at chorionic villus sampling. Based on this and previous reports, we suggest that in cases of a phenotypic discordance detected at ultrasound in the first trimester, it is advisable to perform a karyotype analysis on amniocytes because it better reflects fetal constitution rather than chorionic villi or lymphocytes in case of heterokaryotipic monosomy X monochorionic twins.

Cytogenetic and molecular evaluation of 241 small supernumerary marker chromosomes: cooperative study of 19 Italian laboratories.

PURPOSE: We evaluated the experiences of 19 Italian laboratories concerning 241 small supernumerary marker chromosomes (sSMCs) with the aim of answering questions arising from their origin from any chromosome, their variable size and genetic content, and their impact on the carrier's phenotype. METHODS: Conventional protocols were used to set up the cultures and chromosome preparations. Both commercial and homemade probes were used for the fluorescent in situ hybridization analyses. RESULTS: A total of 113 of the 241 sSMCs were detected antenatally, and 128 were detected postnatally. There were 52 inherited and 172 de novo cases. Abnormal phenotype was present in 137 cases (57%), 38 of which were antenatally diagnosed. A mosaic condition was observed in 87 cases (36%). In terms of morphology, monocentric and dicentric bisatellited marker chromosomes were the most common, followed by monocentric rings and short-arm isochromosomes. The chromosomes generating the sSMCs were acrocentric in 132 cases (69%) and non-acrocentric chromosomes in 60 cases (31%); a neocentromere was hypothesized in three cases involving chromosomes 6, 8, and 15. CONCLUSION: The presented and published data still do not allow any definite conclusions to be drawn concerning karyotype-phenotype correlations. Only concerted efforts to characterize molecularly the sSMCs associated or not with a clinical phenotype can yield results suitable for addressing karyotype-phenotype correlations in support of genetic counseling.

Monitorizaçäo eletrocardiográfica ambulatorial: comparaçäo entre alteraçöes isquêmicas do segmento ST e a cinecoronariografia / Ambulatory electrocardiographic monitoring: a comparison of st-segment depression with coronary angiography

Objetivo Avaliar correlação entre alterações do segmento ST indicativas de isquemia miocárdica, detectadas pela monitorização eletrocardiográfica ambulatorial, e os achados da cinecoronariografia. Métodos— Cinqüenta pacientes, 48 homens, com idades entre 20 e 73 (média 49 ± 13) anos, divididos em três grupos: I) assintomático (16 pacientes, 32%); II) precordialgia atípica (15 pacientes, 30%); e III) angina (19 pacientes, 38%). Procedeu-se à monitorização eletrocardiográfica ambulatorial por período de 24 horas, utilizando-se o sistema Cardiac Care Units (Compass TM). Os pacientes que apresentaram alterações do segmento ST, compatíveis com isquemia miocárdica transitória foram submetidos à cinecoronariografia. Quando esta foi considerada normal, o estudo foi complementado pela ecocardiografia e pelo teste de esforço. Resultados A presença de doença coronária ateroesclerótica (lesões obstrutivas ou fluxo lento) foi constatada em 24 (48%) pacientes. Em 26 (52%) pacientes, as artérias coronárias se apresentaram normais. Dentre esses, em 18 (36%) a ecocardiografia mostrou alqum tipo de afecção ou alteração anatômica (hipertrofia ventricular esquerda, prolapso da valva mitral, hipertrofia septal não obstrutiva, miocardiopatia dilatada). O ecocardiograma foi normal em 8 (16%) pacientes, dos quais em 5 (10%), o teste de esforço foi negativo, entre os quais 1 paciente (2% ) apresentava ponte miocárdica para a artéria descendente anterior, 2 (4%) alterações sintomáticas do segmento ST, e outros 2 paci entes (4%) eram assintomáticos...

Purpose To determine the usefulness of an ambulatory electrocardiographic monitoring system, in identifying atherosclerotic coronary artery disease among symptomatic and asymptomatic patients, through a comparison of ST-segment depression with angiographic findings. Methods Fifty patients, 48 men, with the mean age 49 ± 13 years (range 20 to 73), presenting ST-segment depression, were submitted to coronary angiography, complemented by echocardiogram and exercise testing, when the angiography was considered normal. According to the symptoms patients were divided into three groups: Iasymptomatic (16-32%); II¾ atypical chest pain (15-30%); and IIIangina (19-38%). The Cardiac Care Units(Compass TM) system was used for the ambulatory electrocardiographic monitoring.Results Twenty-four patients (48%) had significant atherosclerotic coronary artery disease documented angiographically. Twenty-six patients (52%) had normal coronary arteries by angiography: 18 (36%), presented some pathology demonstrated by echocardiographic studies (left ventricle hypertrophy, mitral valve prolapse, non-obstructive septal hypertrophy, dilated cardiomyopathy). Eight patients (16%) had normal echocardiograms, and in (6%) the exercise test was positive and in the other 5 (6%) negative. One of those patients (2%), with negative exercise test, had a myocardial bridge over the anterior descending branch of the left coronary artery, 2 patients (4%) presented symptomatic episodes of ST depression, and 2 other patients (4%) were assymptomatic...