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PubMed1998

Defects in limb, craniofacial, and thymic development in Jagged2 mutant mice.

The Notch signaling pathway is a conserved intercellular signaling mechanism that is essential for proper embryonic development in numerous metazoan organisms. We have examined the in vivo role of the Jagged2 (Jag2) gene, which encodes a ligand for the Notch family of transmembrane receptors, by making a targeted mutation that removes a domain of the Jagged2 protein required for receptor interaction. Mice homozygous for this deletion die perinatally because of defects in craniofacial morphogenesis. The mutant homozygotes exhibit cleft palate and fusion of the tongue with the palatal shelves. The mutant mice also exhibit syndactyly (digit fusions) of the fore- and hindlimbs. The apical ectodermal ridge (AER) of the limb buds of the mutant homozygotes is hyperplastic, and we observe an expanded domain of Fgf8 expression in the AER. In the foot plates of the mutant homozygotes, both Bmp2 and Bmp7 expression and apoptotic interdigital cell death are reduced. Mutant homozygotes also display defects in thymic development, exhibiting altered thymic morphology and impaired differentiation of gamma delta lineage T cells. These results demonstrate that Notch signaling mediated by Jag2 plays an essential role during limb, craniofacial, and thymic development in mice.

Animals↗

PubMed1996

[The Adams-Oliver syndrome in Spain: the epidemiological aspects].

Adams and Oliver (1945) described a family with several affected individuals with terminal transverse limb reduction defects and aplasia cutis congenita of the scalp. The clinical expression was highly variable and the pattern showed a family transmission compatible with an autosomal dominant condition. Since the first description, many cases have been published with this pattern of anomalies being known as Adams-Oliver syndrome. Here we present five affected patients ascertained among the 21,835 malformed infants registered by the Spanish Collaborative Study of Congenital Malformations (ECEMC). Epidemiological aspects and clinical features of the patients are presented and compared with data from the literature.

Abnormalities, Multiple↗

PubMedDate not supplied

Giant aplasia cutis congenita without associated anomalies.

Aplasia cutis congenita is a congenital condition in which skin, bone, and dura can be absent. The condition can present in isolation or with associated conditions such as limb anomalies or embryologic malformations. The majority of cases affect the scalp and are limited to the dermis and epidermis. Vertex aplasia cutis typically range in size from 0.5 to 3 cm. The rare larger scalp defects are prone to complications of hemorrhage and infection, and subsequently patients are at risk for death. For these reasons, surgical intervention for large defects may be required. We report the case of a 12-month-old Haitian boy who presented with aplasia cutis congenita of the scalp involving 10 cm of skin and 9 cm of underlying bone. There were no other associated anomalies.

Ectodermal Dysplasia↗

PubMedDate not supplied

[Lesions of the central nervous system in Adams-Oliver's syndrome].

The authors report two cases of Adams-Oliver syndrome in 2-year-old children characterized by aplasia cutis congenita and terminal congenital abnormalities of the limbs. The diagnosis was made at birth and the aplasia cutis was associated with extensive skull defects, exposing the dural sinuses. The differences between the two patients were essentially the extension and the severity of the scalp and limb osteo-cutaneous lesions, associated malformations of the central nervous system and complications. In one child we found focal hemimegalencephaly of the right hemisphere and in the other one the syndrome was complicated by encephaloclastic cerebral lesions and encephalic herniation. Both children have survived, but the diagnosis of central nervous system malformations and the encephaloclastic lesions associated modified the initial prognosis and the future outcome conspicuously.

Abnormalities, Multiple↗

PubMed1992

Child with manifestations of dermotrichic syndrome and ichthyosis follicularis-alopecia-photophobia (IFAP) syndrome.

We report on a boy with short stature, mental retardation, seizures, follicular ichthyosis, generalized alopecia, hypohydrosis, enamel dysplasia, photophobia, congenital aganglionic megacolon, inguinal hernia, vertebral, renal and other anomalies, and a normal chromosome constitution. The clinical findings include all the features that dermotrichic and ichthyosis follicularis-alopecia-photophobia (IFAP) syndrome have in common and in addition those that characterize IFAP syndrome (photophobia, recurrent respiratory infections, etc.), those that are present only in dermotrichic syndrome (nail anomalies, hypohydrosis, megacolon, vertebral defects, etc.) and additional ones (enamel dysplasia, renal anomalies, inguinal hernia, etc.). Two maternal uncles were referred as being affected by alopecia and ichthyosis suggesting X-linked recessive transmission. Various hypotheses concerning the relationship between the 2 syndromes and the present case are discussed.

Alopecia↗

PubMed1999

The recombinant limb as a model for the study of limb patterning, and its application to muscle development.

The recombinant limb is a model system that has proved fruitful for analyzing epithelial-mesenchymal interactions and understanding the functional properties of the components of the limb bud. Here we present an overview of some of the insights obtained through the use of this technique. Among these are the understanding that fore or hind limb identity is inherent to the limb bud mesoderm, that the apical ectodermal ridge (AER) is a permissive signaling center and that the limb bud ectoderm plays a central role in the control of dorsoventral polarity. Recombinant limb studies have also allowed the identification of the affected tissue component in several limb mutants. More recently this model has been applied to the study of regulation of gene expressions related to patterning. In this report we use recombinant limbs to analyze pattering of the Pax3 expressing limb muscle cell lineage in the early stages of limb development. In recombinant limbs made without the zone of polarizing activity (ZPA), myoblasts appear intermingled with other mesodermal cells at the beginning of the recombinant limb development. Rapidly thereafter, the muscle precursors segregate and organize around the central forming chondrogenic core of the recombinant. Although this segregation is reminiscent of that occurring during normal development, the myoblasts in the recombinant fail to proliferate appropriately and also fail to migrate distally. Consequently, the muscle pattern in the recombinant limb is defective indicating that normal patterning cues are absent. However, recombinant limbs polarized with a ZPA exhibited a larger mass of muscle cells and a more normal morphogenesis, supporting a role for this signaling center in limb muscle development. Finally, we have ruled out host somite contributions to recombinant limbs by grafting chick recombinant limbs to quail hosts. This initial report demonstrates the value of the recombinant limb model system for dissecting the environmental cues required for normal muscle limb patterning.

Animals↗

PubMed1994

Thymic hypoplasia and T-cell deficiency in ectodermal dysplasia: case report and review of the literature.

Ectodermal dysplasia is a heterogeneous disorder that includes a constellation of congenital malformations occasionally associated with mild to moderate immune dysfunction. In this report, we describe a female infant with ectodermal dysplasia who was found to have thymic hypoplasia but no other phenotypic features of the DiGeorge anomalad. She experienced Candida parapsilosis sepsis at 1 week of age and a skin infection with Mycobacterium chelonii at 6 months. The numbers of blood B cells were normal and serum immunoglobulins normal to slightly reduced, but serum antibody responses of all immunoglobulin isotypes to protein immunogens were absent. Blood T cells were profoundly reduced and proliferative responses of T cells to mitogens were blunted. In contrast, there was an increased number of natural killer (NK) cells and increased NK activity in the blood. Over the first year of life, some of the immunodeficiencies resolved. Although the numbers of blood T cells (17% of total lymphocytes) remained low, proliferative responses to mitogens normalized and specific antibody responses improved. It seems likely that the thymic hypoplasia in this case was due to a paucity of ectodermal elements in the developing thymus, and that the immune defects were largely secondary to that event. In that respect, this human model of ectodermal dysplasia and thymic hypoplasia resembled the ectodermal/thymic defects found in the nude mouse.

Cell Line↗

PubMed1997

Unilateral somatic and intracranial hypoplasia.

We report on clinical and MR findings in a woman with a peculiar disease. She was studied from childhood to adulthood. She showed several anomalies affecting structures of ectodermal and mesodermal origin. Specific defects included right cerebral and cerebellar hypoplasia, right cerebral cortical polymicrogyria, agenesis of the corpus callosum, right micro-ophthalmia and cataract, right breast hypoplasia, right upper and lower extremity hypoplasia, bilateral acral alterations affecting especially the middle phalanges, left hemifacial hypoplasia (probably secondary to the severe contralateral cerebral hemisphere lesion), mental retardation and partial epilepsy. MR disclosed right cerebral and cerebellar hypoplasia, right cerebral cortical polymicrogyria, agenesis of corpus callosum and right micro-ophthalmia. She did not exhibit either orbital cysts or cutaneous abnormalities. The complex symptomatology of unknown origin presented by this patient suggests a new developmental malformation consisting in hypoplasia of a complete hemibody.

Abnormalities, Multiple↗

PubMed2007

Embryonic expression profile of chicken CHD7, the ortholog of the causative gene for CHARGE syndrome.

BACKGROUND: CHARGE syndrome represents a constellation of malformations: C, coloboma of the iris or retina; H, heart defects; A, atresia of the choanae; R, retardation of growth and/or development; G, genital anomalies; and E, ear abnormalities. Recently, the Chromodomain helicase DNA-binding protein-7 (CHD7) at chromosome 8q12.1 was identified as a causative gene for CHARGE syndrome. Because CHD7 was identified as a causative gene using a positional cloning approach, the role of CHD7 in early embryogenesis needs to be further investigated. METHODS: Fertilized chick eggs were incubated to Hamburger and Hamilton stages 4-20 and were studied using whole mount in situ hybridization. Chicken EST clones corresponding to the chicken CHD7 (cChd7) sequence were identified using the chicken EST sequence database. From the EST clones, a digoxigenin-labeled RNA probe was synthesized and hybridized in situ to the embryonic specimens. RESULTS: The expression of cChd7 was pan-neuronal at stages 8-20. It was expressed throughout the rostral neural ectoderm and along the rostrocaudal axis but was absent from the more lateral, non-neuronal ectoderm. Adjacent to the neural tube, cChd7 transcripts were detected at the optic and otic placodes. At stage 20, cChd7 expression was observed in the branchial arches and olfactory placodes in addition to brain and optic and otic placodes. CONCLUSIONS: cChd7 was expressed in the neural epithelium, the otic placodes, the optic placodes, the branchial arches, and the olfactory placodes, which are the primordial tissues that give rise to organs affected in human CHARGE syndrome patients.

Abnormalities, Multiple↗

PubMed1991

Pathogenesis of limb malformations in mice induced by methoxyacetic acid.

The present study was performed to reveal the pathogenesis of limb malformations induced by methoxyacetic acid (MAA) in developing mouse limbs. Pregnant Jcl:ICR mice were orally given at gestational day (gd) 10.5, 11.0, or 11.5 (vaginal plug = gd 0) a single dose of MAA 10 mmol/kg of body weight. Various patterns of cell death in limb buds were observed by vital dye staining with Nile blue A. Under a light microscope and transmission electron microscope, excessive cell death was observed in the mesenchyme as well as in the apical ectodermal ridge (AER) 2 hr after MAA treatment, reaching a maximum after 6 hr. Scanning electron microscopic examinations showed hypoplasia of the AER and small hand plates 24 hr after treatment. Small hand plates and delayed digital ray formation were noted at 48 hr. Neither detachment nor massive necrosis was detected in the periderm covering the limb bud. The distribution of cell death 6 hr after treatment was similar in limb buds treated either at gd 10.5, 11.0 or 11.5, but the final pattern of limb defects was different in fetuses treated at different stages. This study indicates that variations in the pattern of limb defects induced by MAA are due to differences in the amount and distribution of cell death, together with differences in the regenerative capacity of surviving cells.

Abnormalities, Drug-Induced↗

PubMed2002

Fgf8 is required for pharyngeal arch and cardiovascular development in the mouse.

We present here an analysis of cardiovascular and pharyngeal arch development in mouse embryos hypomorphic for Fgf8. Previously, we have described the generation of Fgf8 compound heterozygous (Fgf8(neo/-)) embryos. Although early analysis demonstrated that some of these embryos have abnormal left-right (LR) axis specification and cardiac looping reversals, the number and type of cardiac defects present at term suggested an additional role for Fgf8 in cardiovascular development. Most Fgf8(neo/-) mutant embryos survive to term with abnormal cardiovascular patterning, including outflow tract, arch artery and intracardiac defects. In addition, these mutants have hypoplastic pharyngeal arches, small or absent thymus and abnormal craniofacial development. Neural crest cells (NCCs) populate the pharyngeal arches and contribute to many structures of the face, neck and cardiovascular system, suggesting that Fgf8 may be required for NCC development. Fgf8 is expressed within the developing pharyngeal arch ectoderm and endoderm during NCC migration through the arches. Analysis of NCC development in Fgf8(neo/-) mutant embryos demonstrates that NCCs are specified and migrate, but undergo cell death in areas both adjacent and distal to where Fgf8 is normally expressed. This study defines the cardiovascular defects present in Fgf8 mutants and supports a role for Fgf8 in development of all the pharyngeal arches and in NCC survival.

Animals↗

PubMed1997

Acute lymphoblastic leukemia in a child with the CHIME neuroectodermal dysplasia syndrome.

The "CHIME" syndrome (MIM#280000) is a rare neuroectodermal disorder comprised of Colobomas of the eye, Heart defects, Ichthyosiform dermatosis, Mental retardation, and Ear defects. We report on the sixth child with this syndrome and the first of these to develop acute lymphoblastic leukemia at age 4 1/2 years. Her major problems included a migratory ichthyosiform dermatosis, multiple skin infections and infestations, bilateral retinal coloboma, developmental delay, seizures, infantile macrosomia, facial anomalies, a duplicated renal collecting system, and conductive hearing loss. Histologic examination of the skin demonstrated findings of an epidermal nevus with deep rete pegs, hyperkeratosis, and a markedly increased granular layer. The cause of the CHIME syndrome is unknown, but the disorder is easily recognized because of the striking phenotype. The diagnosis is important to make because of the potential for associated congenital heart disease, neurologic compromise, possible autosomal recessive inheritance, and possible association with malignancy.

Child, Preschool↗

PubMed2005

Light microscopic examination of scalp hair samples as an aid in the diagnosis of paediatric disorders: retrospective review of more than 300 cases from a single centre.

BACKGROUND: Microscopic examination of scalp hair can provide important diagnostic information in a range of paediatric conditions. It is a non-invasive and cost effective investigation, which is not widely performed. AIMS: To examine retrospectively the value of hair examination by light microscopy, including polarising microscopy, in a specialist paediatric pathology department during a 15 year period (1989-2004) and to describe the morphological abnormalities indicative of specific paediatric conditions. METHODS: Three hundred and twenty two hair samples were submitted. Microscopic changes were analysed in the light of clinical information categorised as: (1) erythroderma, (2) neurological impairment, (3) immunological/haematological defect, (4) ectodermal dysplasia, (5) abnormal hair only, and (6) non-specific/absent clinical details. RESULTS: Abnormalities were evident in 49% of the samples. In 25%, the changes were compatible with specific diagnoses including Menkes disease, Netherton's syndrome, trichothiodystrophy, Griscelli and Chediak-Higashi syndromes, monilethrix, uncombable hair, and loose anagen syndromes. In respect of the clinical presentation groups noted above, diagnostic changes were seen in 41%, 32%, 33%, 0%, 29%, and 0%, respectively. CONCLUSIONS: Morphological light microscopic examination of scalp hair is an inexpensive, rapid, and non-invasive investigation, which can provide valuable diagnostic information in a range of paediatric conditions.

Adolescent↗

PubMed1998

Cranial and cardiac neural crest defects in endothelin-A receptor-deficient mice.

Neural crest cells arise in the dorsal aspect of the neural tube and migrate extensively to differentiate into a variety of neural and non-neural tissues. While interactions between neural crest cells and their local environments are required for the proper development of these tissues, little information is available about the molecular nature of the cell-cell interactions in cephalic neural crest development. Here we demonstrate that mice deficient for one type of endothelin receptor, ETA, mimic the human conditions collectively termed CATCH 22 or velocardiofacial syndrome, which include severe craniofacial deformities and defects in the cardiovascular outflow tract. We show that ETA receptor mRNA is expressed by the neural crest-derived ectomesenchymal cells of pharyngeal arches and cardiac outflow tissues, whereas ET-1 ligand mRNA is expressed by arch epithelium, paraxial mesoderm-derived arch core and the arch vessel endothelium. This suggests that paracrine interaction between neural crest-derived cells and both ectoderm and mesoderm is essential in forming the skeleton and connective tissue of the head. Further, we find that pharyngeal arch expression of goosecoid is absent in ETA receptor-deficient mice, placing the transcription factor as one of the possible downstream signals triggered by activation of the ETA receptor. These observations define a novel genetic pathway for inductive communication between cephalic neural crest cells and their environmental counterparts.

Animals↗

PubMed1979

[Jadassohn's nevus sebaceus and nevus unius lateris. Report of an observation with multiple dysplasia (author's transl)].

The case of a female patient with multiple ectodermal and mesodermal malformations present since birth is reported. The cutaneous lesions were of two types: Jadassohn's nevus sebaceus and nevus unius lateris. These entities have been described in the literature as congenital dermatologic alterations of nevoid character and organoid structure. They can be considered as congenital epidermal nevi. In many cases, including this one, there are various associated disorders especially of the nervous system, eyes, and skeleton. Both syndromes are cutaneous hamartomas which can be differentiated histologically but not by the anomalies accompanying them. Their dermatologic aspects are very similar. The histopathologic characteristics of the skin lesions of nevus unius lateris consist of hyperkeratosis, acanthosis, and epidermal papillomatosis. In Jadassohn's nevus sebaceus there are also alterations of the skin adnexa, namely the absence of hair follicles and the presence of numerous mature sebaceus and hyperplastic glands. In general, the presence of organoid nevus may be a sign of multiple ectodermal and mesodermal malformations. Both syndromes are often present in the same patient, as in the case described here, and their etiology is the same. It is based on an alteration in embryogenic development affecting primarily, though not exclusively, the formations of ectodermal origin. Thus Jadassohn's nevus sebaceus and nevus unius lateris are both forms of phacomatosis. Clinical cases have in common the cutaneous cited above, either in combination or singly. The other possible signs and symptoms are variable, depending on which stage of embryogenic development is affected. There may be defects in the structures of both ectodermal and mesodermal origin.

Adult↗

PubMed2006

Recent advances in craniofacial morphogenesis.

Craniofacial malformations are involved in three fourths of all congenital birth defects in humans, affecting the development of head, face, or neck. Tremendous progress in the study of craniofacial development has been made that places this field at the forefront of biomedical research. A concerted effort among evolutionary and developmental biologists, human geneticists, and tissue engineers has revealed important information on the molecular mechanisms that are crucial for the patterning and formation of craniofacial structures. Here, we highlight recent advances in our understanding of evo-devo as it relates to craniofacial morphogenesis, fate determination of cranial neural crest cells, and specific signaling pathways in regulating tissue-tissue interactions during patterning of craniofacial apparatus and the morphogenesis of tooth, mandible, and palate. Together, these findings will be beneficial for the understanding, treatment, and prevention of human congenital malformations and establish the foundation for craniofacial tissue regeneration.

Animals↗

PubMed2005

Speculations on the pathogenesis of CHARGE syndrome.

To be seriously considered, a theory about the pathogenesis of a multiple congenital anomaly syndrome should meet three criteria: (1) it should explain all of the anomalies associated with the syndrome; (2) it should explain why certain anomalies are not associated with the syndrome; and (3) it should predict anomalies that could be associated with the syndrome, but have not yet been described. The theory must eventually pass the ultimate test, that is, molecular confirmation of the proposed mechanism. Several theories about the pathogenesis of CHARGE syndrome have been proposed, but none of these meet the three criteria stated above. In this study, the author proposes that CHARGE syndrome is due to a disruption of mesenchymal-epithelial interaction (epithelial includes ectoderm and endoderm). The theory is tested against the major, minor, and occasional anomalies that are used to make the clinical diagnosis of CHARGE syndrome. Review of the known embryology of the organs and tissues involved in CHARGE syndrome confirms that mesenchymal-epithelial interactions are necessary for proper formation of these organs and tissues. The presence of limb anomalies in approximately one-third of CHARGE syndrome patients fulfills criteria #3 above, in that limb anomalies were not felt to be a part of CHARGE syndrome until relatively recently. It is known that some patients with chromosomal abnormalities have a phenotype that overlaps with CHARGE syndrome. Given that critical developmental pathways must be robust and redundant in order to minimize errors, it may be that disruption of more than one gene is necessary to generate the CHARGE phenotype, as has been proposed for the holoprosencephaly sequence. Mutations and deletions of CHD7 have recently been identified as causing CHARGE syndrome in more than 50% of tested patients. Given this gene classes' putative role as a general controller of developmental gene expression as well as mesodermal patterning, it would fit the hypothesized mechanisms discussed in the study.

Abnormalities, Multiple↗

PubMed2000

Costello syndrome: report of six patients including one with an embryonal rhabdomyosarcoma.

UNLABELLED: Costello syndrome was first described in 1971. Besides papillomata, which were part of the initial description, patients tends to develop benign tumours of ectodermal origin. Aetiology is yet unknown but it is supposed to be the result of a sporadic dominant mutation. We report six patients with typical clinical findings and emphasise the importance of cardiac manifestations and the tendency to develop tumours. One patient developed an embryonal rhabdomyosarcoma, the occurrence of which has been reported twice before in patients with Costello syndrome. CONCLUSION: There might be a causal link between the development of rare tumours and this genetic disorder which may provide a new clue concerning the identification of the gene involved in Costello syndrome.

Cardiomyopathy, Hypertrophic↗