ISSN:0148-7299    

DOI:10.1002/ajmg.1320310507

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractPositional information on tooth morphogenesis is investigated by the identification of when and where phenotypic markers are expressed during odontogenesis. This temporal and positional information is correlated with the instructive and permissive signaling required for both dentinogenesis and amelogenesis. Of particular interest is the establishment of a map for the cranial neural crest‐derived dental papilla ectomesenchyme and the odontoblast cell lineages. The expression of ectomesenchymederived cytotactin, dentin phosphoprotein, and epithelial‐derived enamel proteins was studied in mice using embryonic, fetal, and postnatal mandibular first molar tooth organ development. This review summarizes the observations in the context of instructive epithelial‐mesenchymal interactions and suggests that amelogenesis imperfecta and dentinogenesis imperfecta may in part be explained by alterations in these differentiation markers. Recombinant DNA methods should facilitate future investigations of these inherited dental diso

ISSN:0148-7299    

DOI:10.1002/ajmg.1320310508

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThis review describes the application of new techniques for examining some longstanding questions in the neural crest system concerning pathways of migration, cell lineage decisions, and importance of the extracellular matrix. The first issue examined involves the migratory pathways followed by neural crest cells. In birds, it has been possible to map crest migratory routes accurately using antibodies that selectively recognize neural crest cells. These antibodies permit the identification of migrating cells in the absence of the surgical trauma incurred by neural tube transplantations. In amphibian embryos, which are more readily accessible to embryological manipulation than are birds, neural fold grafts using two new cell markers have made it possible to map the early stages of neural crest migration using both interspecific and intraspecific chimerae. In both birds and amphibians, a metameric pattern of neural crest migration was observed; this presumably results from interactions with the adjacent somites.A second novel experimental paradigm tests the role of cell surface–extracellular matrix interactions in neural crest migration. Using antibodies to perturb interactions between the cell surface and the extracellular matrix selectively, it has been possible to identify some molecular interactions that are important for aspects of neural crest migration in situ.New techniques have also made it possible to examine the cell lineage decisions of neural crest cells. Using a retrograde labeling technique and a method of microinjecting cells into embryos, we have found that neural crest‐derived cholinergic neurons remain plastic with respect to their neurotransmitter expression even after overt differentiation. New cell‐marking techniques have made it possible to study neural crest cell lineage by means of clonal analysis. Individual neural crest precursors can be injected with a cell lineage tracer that is passed to all of its progeny. Thus, we can examine the developmental potential of individual neural crest cells. The various experimental paradigms presented in this review illustrate the utility of recent technological advances to study embryological questions that have long concerned investigators interested in the neural crest and in other developmental sy

ISSN:0148-7299    

DOI:10.1002/ajmg.1320310509

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe oculoauriculovertebral anomaly is a complex developmental field defect. There is lack of agreement on the minimal diagnostic criteria and the phenotypic spectrum. Causal heterogeneity has been described. This report reviews aspects of phenotypic variability and causal heterogeneity and discusses current understanding of the defect.

ISSN:0148-7299    

DOI:10.1002/ajmg.1320310510

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractIn 1969, McKusick discussed the nosology of genetic disease and the importance of considering heterogeneity and variability. Those considerations are still important today in that new syndromes are being described at the rate of one or more per week. However, often a “new” syndrome actually represents variable expression of a previously described condition; at other times, a child is reported as having a variant of a previously described syndrome when in reality that child has a distinct condition. The concepts of variability and heterogeneity will be discussed in the context of recently described findings in some “old” syndromes, thus shedding new light

ISSN:0148-7299    

DOI:10.1002/ajmg.1320310511

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThis report surveys literature on four syndromes with major manifestations in the craniofacial region, i.e., Laband syndrome, de Barsy syndrome, Wiedemann‐Rautenstrauch syndrome, and LADD syndrome. In general, these four syndromes are better described in the European than in the North American literature. In addition, we report on a newly diagnosed woman having the Laband syndrome and normal intelligence. Finally, we describe a possibly “new” craniofacial syndrome in a mother and he

ISSN:0148-7299    

DOI:10.1002/ajmg.1320310512

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractTwo models concerning morphometric traits occurring frequently in aneuploidy states posit, respectively, (1) that they reflect the expression of specific major oligogenes for that trait on the chromosome involved or (2) that they result from a generalized disruption of developmental homeostasis. In contrast to previous studies that have investigated variations in morphometric traits in a single aneuploidy state, this study investigates a single morphometric trait, taurodontism, as it occurs in otherwise normal individuals, in nonchromosomal syndromes, and in aneuploidy syndromes to determine whether the trait best fits the oligogene or the disrupted developmental homeostasis model. Taurodontism is diagnosed from dental radiographs. It is an extreme variation in tooth form seen in multirooted teeth in which the bifurcation or trifurcation of the roots is displaced toward the apex of the root, resulting in increased size of the pulp chamber. The point of furcation, and consequently the size of the pulp chamber, is a quasicontinuously distributed trait. The results indicate that taurodontism most likely is the result of disrupted developmental homeostasis.

ISSN:0148-7299    

DOI:10.1002/ajmg.1320310513

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractInformation on craniosynostosis in this paper updates “Craniosynostosis: Diagnosis, Evaluation, and Management” (Cohen MM Jr: New York: Raven Press, 1986). It also discusses recent developments that were included in the book but need further explanation or emphasis. Subjects discussed are: epidemiology, etiology, sutural biology, growth and development, neurological and psychosocial aspects, surgery, cloverleaf skulls, craniosynostosis syndromes, and prenatal diagnosis. Under the subject of etiology, fetal head constraint, maternal thyroid disease, calcified cephalohematoma, teratogens, and delayed suture closure and Wormian bones are considered. An updating of 15 cloverleaf skull conditions includes four monogenic disorders, two chromosomal disorders, one disruption, one iatrogenic condition, and seven syndromes of unknown cause. Newly recognized disorders with cloverleaf skull include Beare‐Stevenson cutis gyratum syndrome and Say‐Poznanski syndrome. Craniosynostosis syndromes and associations discussed include acrocraniofacial dysostosis, Apert syndrome, Beare‐Stevenson cutis gyratum syndrome, Calabro syndrome, calvarial hyperostosis, chromosomal craniostenosis, Cole‐Carpenter type osteogenesis imperfecta, Crouzon syndrome, Curry‐Jones syndrome, Curry variant of Carpenter syndrome, cutis aplasia and cranial stenosis, Fontaine‐Farriaux syndrome, Gomex‐López‐Hernández syndrome, Hersh syndrome, hyper‐IgE syndrome and craniostenosis, hypomandibular faciocranial dysostosis, Marfanoid features and craniostenosis, Pfeiffer‐type cardiocranial syndrome, Pfeiffer‐type dolichocephalosyndacty

ISSN:0148-7299    

DOI:10.1002/ajmg.1320310514

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe oral‐facial‐digital syndromes are a heterogeneous group of conditions sharing oral, facial, and digital anomalies. Based on more or less subtle clinical differences, at least seven causally different entities can be identified in this group. These include (1) oral‐facial‐digital syndrome (OFDS) I; (2) Mohr syndrome (OFDS II); (3) OFDS III; (4) OFDS with tibial anomalies (OFDS IV); (5) Thurston syndrome; (6) Varadi syndrome; and (7) Whelan syndrome. However, since differentiation between these entities is based on clinical findings, this classification should be viewed as tentative until more definitive methods are av

ISSN:0148-7299    

DOI:10.1002/ajmg.1320310515

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractWe describe a severe first branchial arch abnormality including nearly complete absence of mandible, hypoplasia of the maxilla and the zygomatic arches, and complete gingival fusion in a chromosomally normal child born to a nonconsanguineous couple who deny prenatal exposures. A tight orbicularis oris muscle caused the lips to be constantly pursed. Intraoral contents could only be defined after the fused gingiva were separated. The infant had hypoplasia of the buccal cavity with a persistent membrane separating it from the pharynx; palate structures and tongue were absent. The orbits and midface were severely hypoplastic. However, the ears were normal in shape and only slightly low in position. There was unilateral optic nerve coloboma and coronal craniosynostosis. The only noncraniofacial malformation was an atrial septal defect. Embryologically, there is severe malformation of structures arising from the cephalic neural crest cells of both the maxillary and mandibular prominences of the first branchial arch. However, the first branchial cleft region was spared.

ISSN:0148-7299    

DOI:10.1002/ajmg.1320310516

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY