RESUMO
We describe an infant with multiple dysmorphic features who is mosaic for duplication 17q21.1----qter, owing to a direct tandem duplication. He is the first case with mosaicism for a 17q duplication to be reported. His features are strikingly suggestive of Ellis-van Creveld syndrome.
Assuntos
Aberrações Cromossômicas , Cromossomos Humanos Par 17 , Síndrome de Ellis-Van Creveld/genética , Mosaicismo , Bandeamento Cromossômico , Humanos , Recém-Nascido , Masculino , FenótipoRESUMO
With the combination of the various banding techniques (G,Q, and R), a small deletion of the short arm of a No.5 chromosome was detected prenatally in the pregnancy of a 39-year-old woman. The deletion appeared to be either intersitial in nature, involving part of p13 and p14, or the result of a translocation with deletion of p13 leads to pter. Both parents were found to have a normal chromosome constitution with normal banding patterns. Thus, this deletion was a de novo event. Repeat amniotic fluid cell chromosome analysis at the time of elective abortion, and postmortem examination of the fetus confirmed the prenatal cytogenetic diagnosis. We wish to emphasize that precise identification of a small deletion, as in this case, requires a combination of the various banding techniques.
Assuntos
Deleção Cromossômica , Cromossomos Humanos 4-5 , Síndrome de Cri-du-Chat/diagnóstico , Diagnóstico Pré-Natal , Aborto Induzido , Líquido Amniótico/citologia , Síndrome de Cri-du-Chat/genética , Feminino , Humanos , Idade Materna , GravidezRESUMO
From February 1969 to August 1976, we studied 1,048 amniotic fluids. Of these, 958 (91.4%) were primarily for prenatal cytogenetic diagnosis. Cytogenetic studies were attempted in 1,021 cases; the diagnosis was successful in 1,000 of these. The failure rate of obtaining a diagnosis from the amniotic fluid cell culture of the first amniocentesis was 5% (50 cases); 29 cases had a repeat tap and successful diagnosis was achieved in all. In 21 cases, a repeat tap was refused. Thus, the overall failure rate of obtaining a final cytogenetic diagnosis was 2.06% (21/1,021). There were 32 fetal losses after amniocentesis including 16 spontaneous second trimester abortions, 7 fetal deaths in utero and 9 stillbirths. In two additional cases, fetal death had occurred before amniocentesis. This number of fetal losses does not exceed the number that would be expected in the same maternal age group without amniocentesis. In our series, the frequencies of trisomy in maternal age groups 40 years and over, 37-39 years, 35-36 years, and under 35 years were 4.5, 3.14, 0 and 0% respectively. These frequencies are comparable to those reported from other prospective prenatal studies and higher than those of retrospective live born studies. Various problems and pitfalls in prenatal cytogenetic diagnosis are discussed.
