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Biomedical subjects

E Engel

Publications and source records attributed to E Engel.

At least 145 records · Page 8Linked to original sources
PubMed1981

[Distinctive features of euploid-aneuploid mosaicisms diagnosed by amniocentesis (author's transl)].

Although infrequent, mosaicism in amniotic fluid may lead to a questionable diagnosis. From a personal case and a general review of the literature the authors conclude that euploid-aneuploid mosaicism must be strongly considered as real if it is expressed in more than one clone, in more than one flask, if it is confirmed by a second amniocentesis and if the abnormal cell line is caused by the loss or acquisition of a chromosome compatible with a known pattern or syndrome. Other patterns documented in such a material have to be considered on their own merits as they may or may not be confirmed after birth.

Amniocentesis↗
PubMed1981

[Multisynostotic osterodysgenesis and the problem of genetic counseling in newly-identified syndromes (author's transl)].

The authors report two female infants affected with a skeletal malformation syndrome, recently identified and probably genetic in nature, which includes as principal features a craniosynostosis with secondary midfacial hypoplasia and a characteristic facies. More specifically, the skeletal alterations include synostosis of the radius and humerus, congenital bowing of the femurs with fracturing during the neonatal period, and other minor anomalies of the thorax and extremities. The differential diagnosis includes serveral skeletal dysplasias such as the Campomelic syndrome, certain of the Acrocephalosyndactylies, and Osteodysgenesis Imperfecta. However, global comparison of the clinical and radiographic features permits their exclusion, allowing the consideration that we are dealing with a new syndrome, which has been named Multisynostotic Osteodysgenesis. The etiology of this disorder has not been elucidated, the two cases being isolated and without parental consanguinity. The authors, however, favor the theory of autosomal dominant inheritance. The difficulty of providing genetic counseling in the case of such poorly-understood syndromes is emphasized.

Abnormalities, Multiple↗
PubMed1980

The syndrome of multisynostotic osteodysgenesis with long-bone fractures.

Described here are two patients with a newly recognized syndrome of bone and cartilage maldevelopment which, we believe, results from a single embryonic defect, probably of genetic origin. The cardinal manifestations of this association are craniosynostosis, radiohumeral synostosis (RHS), and femoral bowing. Specific secondary defects include midface hypoplasia with characteristic facial appearance and ears, neonatal femoral fractures, and multiple minor anomalies of the limbs. Though the differential diagnosis includes such disorders as the campomelic syndrome, osteogenesis imperfecta (OI) and certain of acrocephalosyndactyly syndromes, the unique combination of clinical and radiographic abnormalities allows ready differentiation. The cause cannot be determined from these two cases.

Bone Diseases, Developmental↗
PubMed1980

Genetic and endocrine findings in a 48,XXYY male.

Characteristics of a 16-yr-old male with a 48,XXYY karyotype are presented; this chromosome constitution was demonstrated consistently in four tissue studied. Basal gonadotropins were elevated, and serum testosterone varied between 3.2-4.0 ng/ml. A pronounced rise was observed in LH after LRH administration with a lesser rise of FSH. The testis displayed hyperplasia of the interstitial cells, tubular atrophy, absent spermatogenesis with preservation of some Sertoli cells, and peritubular fibrosis. The phenotypic, behavioral, endocrine and pathological features of this patient are compared with those found in males with the 47,XXY and 47,XYY syndromes. The 48,XXYY phenotype may result from compounding effects of the additional X and Y chromosomes.

Adolescent↗
PubMed1980

[A new genetic concept: the uniparental disomy and its potential effect, the isodisomy (author's transl)].

In recent years, cytogenetic studies of spontaneous abortion products have disclosed the relatively high frequency of aneuploid embryos. These karyotypic anomalies chiefly stem from meiotic errors affecting the distribution of the chromosomes in one of the two gametes fused into a zygote. The gathered information not only implies the remarkable frequency of gonocyte aneusomy, it also reveals the prevalence of certain types of errors. It follows that gametal haploidy is often altered by the loss (nullisomy) or the addition (disomy) of certain members, in particular the X, the Y and chromosomes 15, 16, 21 and 22. It is therefore to be expected that, for some exceptional zygotes, the preservation of euploidy could result from the random union of a disomic gamete with a gamete nullisomic for a same member. To this hypothetical phenomenon, which is however statistically likely and foreseeable, we have ascribed the name of uniparental disomy, owing to the fact that both members of such a pair arise only from one parent, the mother or the father, instead of both. Furthermore, such a mechanism implies the major probability of introducing into the genome pairs of chromosomes with whole sequences of identical alleles, a consequence which we describe by the neologism of isodisomy. Such an extended homozygosity for series of colinear alleles implies from the genetic standpoint risks and advantages akin to those of parental consanguinity. An analogous mechanism could also modulate and modify the consequences of trisomies in which entire segments of two or the three implicated chromosomes, including the supernumerary one, could as well be iso-allelic (isodisomic trisomy or di-isotrisomy). The article briefly states some other predictions steming from the concept of uniparental disomy, whose confirmation should serve as a test of the proposed hypothesis.

Aneuploidy↗
PubMed1980

[The problem of sex chromosome aneuploidy in genetic counseling using amniocentesis].

The identification of chromosomal alterations remains, undeniably, one of the major objectives of prenatal diagnosis by amniocentesis. A series of 500 cases personally tested by the authors confirms entirely the validity of the principal indication for, and the benefit of, this modern method for the intrauterine detection and prevention of many severe congenital chromosome defects. In our experience, the cases of genetic counselling following detection of sex chromosome anomalies have proven to be particularly difficult. In two of three situations where such a diagnosis was revealed (an XYY and XXY fetus), after hours of discussion and reflection, the parents opted to pursue the pregnancies to term. In the third case (an XYY fetus), an abortion was requested. Certain aspects of these decisions are discussed and the opinions of participants solicited.

Abortion Applicants↗
PubMed1979

[Prenatal diagnosis. Review, personal and prospective studies].

1. In a review of methods developed for the identification of fetal malformations, the technique, risks and results of amniocentesis are presented. 2. Large series already published have demonstrated the relative simplicity and feasibility of the procedure as well as current indications for its utilization. These include the detection of chromosomal anomalies, the determination of sex (in certain sex-linked disorders), documentation of enzymatic and metabolic deficiencies, and the demonstration of open lesions of the neural tube by appropriate techniques. 3. Experience with over 500 cases personally tested by the authors entirely confirms the major indications for and benefits of this modern method for the detection and prevention of severe congenital anomalies during early pregnancy. 4. The identification of chromosomal alterations is currently the major objective of the method. Increased risks are associated with pregnancies involving a maternal age of 35 years or older (which account for 1-3% of aneuploidies), the birth of a previous infant with free trisomy 21 (1% recurrence risk) or secondary to a parental chromosome translocation (as much as 10% risk of aneuploidy). Fetal karyotyping for determination of sex, in cases where the mother is a carrier of an X-linked recessive gene (on average, 50% of male offspring will be affected), is an inadequate method of diagnosis to be utilized only until alternative techniques render possible specific diagnosis of the anomalies under consideration (hemophilias A and B, muscular dystrophy, etc). 5. Several of these techniques are now nearing development through the advent of fetoscopy and advanced ultrasound methodology, and have already been applied to the detection of certain sex-linked disorders and also for diagnosis of hemoglobinopathies (thalassemias, sickel cell anemia) and other conditions requiring the obtaining of fetal blood for diagnosis. Technology allowing direct examination of fetal parts by means of optical instruments is particularly useful in cases where a severe fetal morphologic malformation cannot currently be identified by indirect visualization (ultrasound) or by analysis of cytogenetic or molecular markers. 6. Pathological accumulations of alpha-fetoprotein which are associated with diverse feto-placental abnormalities (particularly open malformations of the neural tube) can be detected in the amniotic fluid and/or maternal blood. In extension of this approach, it is foreseeable that conditions existing prenatally will be diagnosed in a growing number of cases from the study of fetal cells and molecules which can be isolated from the venous blood of pregnant women. This will become feasible as a result of some well-developed techniques which allow separation of fetal from maternal cells and metabolites, and also to some extremely fine analytic techniques, notably examination of the DNA itself by means of restriction enzymes.

Adult↗
PubMed1979

Is there an embryo-fetal exogenous sex steroid exposure syndrome (EFESSES)?

A survey of all outpatient cases referred for genetic counseling during a 10-month period has revealed a history of preconceptional and early gestational exposure to maternally administerd sex hormones in 16 of 91 instances. Particular interest was aroused by 9 of these 16 cases, all of whom were children with dysmorphic features, no cytogenetic anomalies by Giemsa banding studies, and no recognizable clinical diagnosis. Similarities among them were striking and consisted of varying combinations of the following features: moderate growth retardation; mild to severe mental retardation; facial elongation with frontal bossing; primary telecanthus and downward-slanting palpebral fissures; broad, flat, nose bridge and pug nose; pouting lower lip and blunt, square chin; umbilical eversion; deep sacral pit; and, in males, moderate to severe external genital anomalies ranging from mild hypospadias to genital ambiguity. This may suggest the existence of an embryo-fetal exogenous sex steroid exposure syndrome.

Abnormalities, Drug-Induced↗
PubMed1979

Hemophilia and the female: considerations for the radiologist.

Hemophilia A and B are commonly considered male diseases because of their X-linked recessive inheritance, but clinical hemophilia is occasionally seen in females. This may represent an extreme example of the Lyon hypothesis in which a heterozygous female has only the one X chromosome bearing the aberrant gene in the active state.

Bone and Bones↗
PubMed1979

Extent and rate of chromosome segregation in two intraspecific mouse cell hybrids: A9 x diploid foetal erythrocyte and A9 x B82.

Patterns of chromosome segregation were studied in 2 different intraspecific mouse cell hybrids: (1) A9 x B82, formed by fusing 2 cell lines of heteroploid fibroblasts, and (2) UWE, originating from the fusion of A9 cells with euploid foetal erythrocytes. Detailed analyses of Giemsa (G)-banded chromosomes and chromosome arms of both parental and hybrid cells were made for each hybrid type, in order to determine the specificity of the losses and to assess the influence of ploidy and cell differentiation. Unlike the A9 x B82 hybrids, which revealed a significant chromosome loss under selective tissue culture pressures only after 9 months, the UWE hybrids showed a sharp reduction in the total chromosome number during the initial 2 months under similar pressures. However, with no additional cloning, UWE remained karyotypically stable after that time. This rapid chromosomal segregation in UWE hybrids may be caused by properties of the parental foetal erythrocytes. In UWE cells, the majority of the chromosome arms were retained or duplicated. Less than a quarter of the total number of chromosome arms were segregated or lost, and these were all chromosome arms with abnormal mouse G-banding patterns, present only in the heteroploid A9 parental cells. In two of the four A9 x B82 hybrid lines, there was marked segregation of chromosome arms whose banding patterns were identical to those of wild type mouse telocentric chromosomes. For both types of intraspecific cell hybrids, two thirds or more of the chromosome arms had banding patterns which were the same as those of the wild type genome.

Animals↗
PubMed1978

Expression of HLA-A, but not of HLA-B, in mouse-human somatic cell hybrids carrying the region p21 leads to pter of human chromosome 6.

Mouse-human somatic cell hybrids containing human chromosome 17 carrying the region p21 leads to pter of human chromosome 6 and no other human chromosomes, were found to express HLA-A but not HLA-B. Counterselection of the hybrid cells in medium containing 5-bromodeoxyuridine resulted in the growth of hybrid cells that have concordantly lost the expression of HLA-A and the human translocation chromosome.

Animals↗