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PubMedDate not supplied

Nevus psiloliparus and aplasia cutis: a further possible example of didymosis.

Nevus psiloliparus is a distinct type of mesodermal nevus of the scalp characterized by absence or paucity of hair, and presence of an excessive amount of fatty tissue. It is considered a hallmark of encephalocraniocutaneous lipomatosis, a rare disorder comprising a variety of cutaneous, ophthalmologic, and neurologic defects. We report two infants with encephalocraniocutaneous lipomatosis with nevus psiloliparus on the scalp in close association with aplasia cutis congenita. This unusual association may be considered a further example of didymosis, for which we propose the term, didymosis aplasticopsilolipara.

Adipose Tissue↗
PubMedDate not supplied

Aplasia cutis congenita in surviving co-twins: four unrelated cases.

Four unrelated patients born from twin pregnancies and showing extracranial aplasia cutis congenita are reported. All the patients lost their co-twins during the first half of the pregnancy. Two of the patients had the characteristic truncal and symmetrical type of aplasia cutis associated with fetus papyraceus and placental abnormalities. The presence of multiple hepatic hematomas in one of them gives further credit to a "vascular disruption" as the possible pathogenetic mechanism of the disorder. The two other patients were born with symmetrical aplasia cutis at the extensory aspects of both knees, which presumably represents a milder expression of the former defect. Thus the so-called aplasia cutis with fetus papyraceus shows heterogeneity in localization, extension, presence of extracutaneous abnormalities, and possible association with fetus papyraceus at birth. To include all the patients affected by this peculiar type of aplasia cutis congenita, the designation of aplasia cutis with extracranial symmetrical involvement is proposed.

Diseases in Twins↗
PubMed2005

Two cases of atypical membranous aplasia cutis with hair collar sign: one with dermal melanocytosis, and the other with naevus flammeus.

We report two atypical cases of membranous aplasia cutis surrounded by a rim of hairs, one case associated with dense dermal melanocytosis and the other with naevus flammeus, with characteristic clinical features. A rim of hypertrichosis, 'hair collar' sign, is proposed to have a close association with neuroectodermal defects. A failure of the normal closure of the cranial neural tube might have affected foetal skin development, including melanoblast migration and capillary network formation. The changes in the present cases, as well as the hair collar sign may suggest a complex hamartomatous nature of membranous aplasia cutis.

Ectodermal Dysplasia↗
PubMed1980

The median nasal sinus and dermoid cyst.

The median nasal sinus and the dermoid cyst of the nose are relatively rare congenital anomalies. The most likely hypothesis for their ontogeny seems to be the retention of ectodermal fragments during closure of the anterior foramen of the neural tube early in embryonal development. The results of the surgical management of fourteen patients with a median dermoid cyst of the nose are discussed. Presenting symptoms were recurrent abscess formation on the dorsum of the nose, a secreting fistula in the median line of the dorsum of the nose, or meningitis. The draining site of the sinus varied less than the location of the dermoid cyst. Treatment consisted in radical excision in a quite stage, using the binocular microscope followed by primary reconstruction of nasal skeletal defects. Anomalies are due not only to development disturbances in the surrounding structures owing to the presence of the sinus and the cyst, but also to growth of the cyst and to infection. Partly for that reason, early surgical management is indicated. It should be preceded by proper radiological examination, because this can provide important clues as to the site of the dermoid cyst. If an endocranial extension has been established preoperatively, a combined ORL and neurosurgical operation is necessary.

Abnormalities, Multiple↗
PubMed2005

RhoA acts downstream of Wnt5 and Wnt11 to regulate convergence and extension movements by involving effectors Rho kinase and Diaphanous: use of zebrafish as an in vivo model for GTPase signaling.

Gastrulation shapes the early embryos by forming three germ layers, ectoderm, mesoderm and endoderm. In vertebrates, this process requires massive cell rearrangement including convergence and extension (CE) movements that involve narrowing and lengthening of embryonic tissues as well as cell elongation. Such polarization and movements require precise reorganization and regulation of the cytoskeleton network and cell adhesion. Rho small GTPases are key regulators for dynamic actin cytoskeleton. However, the signaling mechanisms underlying their functions in CE remain to be further elucidated. We have cloned the zebrafish Danio rerio rhoA and by capitalizing on the specific functional knockdown using morpholinos against rhoA and the availability of CE mutants defective in Wnt signaling, we showed that rhoA morphants were reminiscent to noncanonical wnt mutants with serious disruption in CE movements. Injection of rhoA mRNA effectively rescued such defects in wnt5 and wnt11 mutants. Furthermore, CE defects in rhoA knockdown or wnt mutants can be suppressed through functional bypass after ectopic expression of the two mammalian Rho effectors, the Rho kinase and Diaphanous (mDia). These results provide the first evidence that the RhoA in vivo acts downstream of Wnt5 and Wnt11 to effect, without affecting cell fates, on the CE movements in zebrafish embryos. Significantly, it elicits such effect via both effectors, Rho kinase and Dia. These findings also support the versatility of the zebrafish as a model to further investigate the roles of various classes of small GTPases in regulating cell dynamics in vivo.

Amino Acid Sequence↗
PubMed2001

Focal facial dermal dysplasia or aplasia cutis congenita: a case with a hair collar.

Aplasia cutis congenita describes localized defects of skin that may have many causes. A 6-month-old male presented with bilateral atrophic patches on his cheeks distributed along a line from the preauricular area to the angle of the mouth. They had been present since birth. He had no other abnormalities detectable on examination and no family history of similar lesions. A distinct collar of long pale hairs surrounded the lesions, especially the largest one. Histology showed changes consistent with aplasia cutis congenita or focal facial dermal dysplasia. We propose our patient's lesions may be the result of failure of ectodermal fusion over embryological closure lines. This may be a distinct subgroup of atrophic facial lesions.

Biopsy, Needle↗
PubMed2001

Regulation of ectodermal and excretory function by the C. elegans POU homeobox gene ceh-6.

Caenorhabditis elegans has three POU homeobox genes, unc-86, ceh-6 and ceh-18. ceh-6 is the ortholog of vertebrate Brn1, Brn2, SCIP/Oct6 and Brn4 and fly Cf1a/drifter/ventral veinless. Comparison of C. elegans and C. briggsae CEH-6 shows that it is highly conserved. C. elegans has only three POU homeobox genes, while Drosophila has five that fall into four families. Immunofluorescent detection of the CEH-6 protein reveals that it is expressed in particular head and ventral cord neurons, as well as in rectal epithelial cells, and in the excretory cell, which is required for osmoregulation. A deletion of the ceh-6 locus causes 80% embryonic lethality. During morphogenesis, embryos extrude cells in the rectal region of the tail or rupture, indicative of a defect in the rectal epithelial cells that express ceh-6. Those embryos that hatch are sick and develop vacuoles, a phenotype similar to that caused by laser ablation of the excretory cell. A GFP reporter construct expressed in the excretory cell reveals inappropriate canal structures in the ceh-6 null mutant. Members of the POU-III family are expressed in tissues involved in osmoregulation and secretion in a number of species. We propose that one evolutionary conserved function of the POU-III transcription factor class could be the regulation of genes that mediate secretion/osmoregulation.

Amino Acid Motifs↗
PubMed2002

Management of aplasia cutis congenita in a non-scalp location.

We report the conservative management of a newborn with extensive aplasia cutis congenita of the thighs, associated with a monochorionic co-twin foetus papyraceous. The skin defects on both thighs, measuring 340 cm2, healed in 38 days. The child was treated under medical supervision on an outpatient basis, with regular dressing changes at home by a district nurse. During the healing period, no local or systemic complications were noted. At 1 year follow-up the scars were stable with an acceptable appearance.

Bandages↗
PubMed1995

Dachsous encodes a member of the cadherin superfamily that controls imaginal disc morphogenesis in Drosophila.

Mutations in the dachsous gene of Drosophila lead to striking defects in the morphogenesis of the thorax, legs, and wings. The dachsous gene has been cloned and shown to encode a huge transmembrane protein that is a member of the cadherin superfamily, similar to the fat gene reported previously. Both the Dachsous and Fat proteins contain large tandem arrays of cadherin domains--27 and 34, respectively--as compared with 4 cadherin domains in classic vertebrate cadherins. In addition, Dachsous and Fat each has a cytoplasmic domain with sequence similarity to the cytoplasmic beta-catenin-binding domain of classic vertebrate cadherins. The dachsous gene is expressed in the ectoderm of embryos, whereas its expression in larvae is restricted to imaginal discs and specific regions of the brain. The phenotypes of, and genetic interactions between dachsous and fat are consistent with a model in which cell proliferation and morphogenesis of imaginal structures depends on the coupled equilibria between homo- and heterophilic interactions of the Dachsous and Fat cadherin proteins.

Alleles↗
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↗
PubMed2002

Complete osseous regeneration of a large skull defect in a patient with cutis aplasia: a conservative approach.

Cutis aplasia (or aplasia cutis congenita) is a congenital absence of all skin layers, often extending through bone. This defect usually occurs in the scalp and can be extensive, exposing the dura mater, and deeper meninges. Treatment regimens for cutis aplasia have included early operative intervention, including skin and bone grafts, local scalp flaps, or free flaps to close the defect. In addition to the significant perioperative risks, these invasive procedures may inhibit the osteogenic potential of the dura to initiate and sustain bony closure of the defect. We report a case of an infant with Adams-Oliver syndrome and cutis aplasia involving a large portion of the skull that was treated conservatively with topical Silvadene dressings. No surgical treatment of bone or soft tissue reconstruction was necessary. This case report is the first to our knowledge to document complete bony restoration of the cranial vault through serial three-dimensional CT scans. The intensive therapeutic intervention in this case report allowed early discharge from the hospital, a gradual amelioration of the patient's alopecia as the hair-bearing scalp slowly covered the defect, and precluded the need for any subsequent bony reconstruction of the cranial vault. We hypothesize that conservative treatment of cutis aplasia maintains dural induction of osseous regeneration, and any treatment plan for bony defects of cutis aplasia should consider maintenance of dural integrity. Although further investigation is warranted, an initial trial of antimicrobial dressing care might optimally promote secondary closure of the cranial vault without the need for surgical intervention.

Administration, Cutaneous↗
PubMed2005

DNA-binding and transactivation activities are essential for TAp63 protein degradation.

The p53-related p63 gene encodes six isoforms with differing N and C termini. TAp63 isoforms possess a transactivation domain at the N terminus and are able to transactivate a set of genes, including some targets downstream of p53. Accumulating evidence indicates that TAp63 plays an important role in regulation of cell proliferation, differentiation, and apoptosis, whereas transactivation-inert deltaNp63 functions to inhibit p63 and other p53 family members. Mutations in the p63 gene that abolish p63 DNA-binding and transactivation activities cause human diseases, including ectrodactyly ectodermal dysplasia and facial clefting (EEC) syndrome. In this study, we show that mutant p63 proteins with a single amino acid substitution found in EEC syndrome are DNA binding deficient, transactivation inert, and highly stable. We demonstrate that TAp63 protein expression is tightly controlled by its specific DNA-binding and transactivation activities and that p63 is degraded in a proteasome-dependent, MDM2-independent pathway. In addition, the N-terminal transactivation domain of p63 is indispensable for its protein degradation. Furthermore, the wild-type TAp63gamma can act in trans to promote degradation of mutant TAp63gamma defective in DNA binding, and the TA domain deletion mutant of TAp63gamma inhibits transactivation activity and stabilizes the wild-type TAp63 protein. Taken together, these data suggest a feedback loop for p63 regulation, analogous to the p53-MDM2 feedback loop.

Amino Acid Motifs↗
PubMed1998

The lines gene of Drosophila is required for specific functions of the Abdominal-B HOX protein.

The Hox genes encode homeobox transcription factors that control the formation of segment specific structures in the anterior-posterior axis. HOX proteins regulate the transcription of downstream targets acting both as repressors and as activators. Due to the similarity of their homeoboxes it is likely that much of the specificity of HOX proteins is determined by interaction with transcriptional cofactors, but few HOX cofactor proteins have yet been described. Here I present genetic evidence showing that lines, a segment polarity gene of Drosophila, is required for the function of the Abdominal-B protein. In lines mutant embryos Abdominal-B protein expression is normal but incapable of promoting its normal functions: formation of the posterior spiracles and specification of an eighth abdominal denticle belt. These defects arise because in lines mutant embryos the Abdominal-B protein cannot activate its direct target empty spiracles or other downstream genes while it can function as a repressor of Ultrabithorax and abdominal-A. The lines gene seems to be required exclusively for Abdominal-B but not for the function of other Hox genes.

Abdomen↗
PubMed1990

An emerging view of vitamin D.

Vitamin D3 (D2 is 22-ene,24-methyl D3) is a prehormone which is hydroxylated by mixed function mono-oxygenase NADPH-cytochrome P-450 ferredoxin/ferredoxin reductase systems in liver parenchyma and renal proximal tubular cells to 25-hydroxy, then 1,25-dihydroxyvitamin D, the active hormone. 1,25-dihydroxyvitamin D binds to a mainly intranuclear receptor in target cells [classically, bone, kidney and gut; now shown to be wider including parathyroid cells, endocrine cells generally and many cells of ectodermal (brain, skin) and mesodermal (blood forming cells, lymphnode cells) origin as well as tumour cells (breast, lymphoma, leukaemia)] and activates transcription for products such as calcium binding proteins, its own receptor protein, 24-hydroxylase and non-specific esterase which are active in calcium homeostasis and cell differentiation. Advanced methods for measuring components of the vitamin D endocrine system have been developed and involve column extractions, liquid chromatographic purifications (also HPLC) and protein and receptor binding assays as well as mass spectrometry. These have facilitated elucidation of vitamin D physiology (also in pregnancy and lactation) and of metabolic defects in classical, vitamin D resistant and renal rickets and osteomalacia, in sarcoidosis and in the possible involvement of the vitamin in cell differentiation, e.g. in myeloid leukaemia, and breast cancer.

Calcium↗
PubMed2000

Dosage requirement and allelic expression of PAX6 during lens placode formation.

Pax6 is a member of the mammalian Pax transcription factor family. Many of the Pax genes display semi-dominant loss-of-function heterozygous phenotypes, yet the underlying cause for this dosage requirement is not known. Mice heterozygous for Pax6 mutations exhibit small eyes (Sey) and in embryos the most obvious defect is a small lens. We have studied lens development in Pax6(Sey)(-1Neu)/+ embryos to understand the basis of the haploinsufficiency. The formation of the lens pre-placode appears to be unaffected in heterozygotes, as deduced from the number of cells, the mitotic index, the amount of apoptosis and the expression of SOX2 and Pax6 in the pre-placode. However, the formation of the lens placode is delayed. The cells at the edge of the lens cup fail to express N-cadherin and undergo apoptosis and the lens fails to detach completely from the surface ectoderm. After formation, the lens, which has 50% of the cells found in wild-type embryos, grows at a rate that is indistinguishable from wild type. We rule out the possibility that monoallelic expression of Pax6 at the time of lens placode formation accounts for the 50% reduction in cell number by showing that expression of Pax6 is biallelic in the lens placode and optic vesicle. We propose instead that a critical threshold of PAX6 protein is required for lens placode formation and that the time in development at which this level is reached is delayed in heterozygotes.

Alleles↗
PubMed2006

Aplasia cutis congenita of the scalp: is there a better treatment strategy?

BACKGROUND: Aplasia cutis congenita (ACC) is a rare disease of unknown etiology, involving any site of the body. The scalp is the most frequent location, followed by the forearms, knees, both sides of the trunk, and neck, in decreasing order of frequency. Superficial lesions may heal spontaneously and seldom result in morbidity or mortality. However, in patients with large scalp and skull defects, there are risks of infection and bleeding. Conservative treatment has been described and advocated, but some authors have highlighted the disadvantages of this treatment modality. On the other hand, several authors claim that aggressive surgical treatment has an important role for large defects. MATERIALS AND METHODS: In this paper, we report three newborns with ACC of the scalp, two large defects and a medium one, respectively, treated conservatively and surgically. CONCLUSION: The management of ACC of the scalp is still controversial. Our series suggests that conservative treatment should be performed for initial management in newborns.

Abnormalities, Multiple↗
PubMed2002

Our experience with aplasia cutis congenita.

Aplasia cutis congenita is a rare disorder characterized by developmental absence of skin on the scalp as multiple or solitary, noninflammatory, well demarcated, oval or circular 1- to 2-cm ulcers. The disease may be isolated or associated with anomalies of the skin, eyes, ear-nose-neck and limbs, developmental defects of the cardiovascular, gastrointestinal, genitourinary and central nervous systems, and malformation syndromes such as chromosomal abnormalities, Adams-Oliver syndrome, Bart's syndrome, and Johanson-Bilzzard syndrome. In this article, five newborn infants with aplasia cutis congenita (one associated with Adams-Oliver syndrome and another concomitant with Bart's syndrome) are reported because of their rare presentation in the literature.

Ectodermal Dysplasia↗
PubMed1998

Surgical management of cutis aplasia with high-flow sinus pericranii.

Cutis aplasia (cutis aplasia congenita cystica) is a rare congenital disorder with failure of completion of the extracerebral coverings, involving a defect in the scalp and often a cranial defect. A case of cutis aplasia is reported with an associated high-flow venous fistula or sinus pericranii, resulting in altered venous drainage of sagittal sinus blood through dilated scalp veins. Radiological workup to ensure patency of the superior sagittal sinus was critical to the surgical management in this case.

Adult↗