LPIN1 deficiency with severe recurrent rhabdomyolysis and persistent elevation of creatine kinase levels due to chromosome 2 maternal isodisomy.

Fatty acid oxidation disorders and lipin-1 deficiency are the commonest genetic causes of rhabdomyolysis in children. We describe a lipin-1-deficient boy with recurrent, severe rhabdomyolytic episodes from the age of 4 years. Analysis of the LPIN1 gene that encodes lipin-1 revealed a novel homozygous frameshift mutation in exon 9, c.1381delC (p.Leu461SerfsX47), and complete uniparental isodisomy of maternal chromosome 2. This mutation is predicted to cause complete lipin-1 deficiency. The patient had six rhabdomyolytic crises, with creatine kinase (CK) levels up to 300,000 U/L (normal, 30 to 200). Plasma CK remained elevated between crises. A treatment protocol was instituted, with early aggressive monitoring, hydration, electrolyte replacement and high caloric, high carbohydrate intake. The patient received dexamethasone during two crises, which was well-tolerated and in these episodes, peak CK values were lower than in preceding episodes. Studies of anti-inflammatory therapy may be indicated in lipin-1 deficiency.

Wnt signaling acts and is regulated in a human osteoblast differentiation dependent manner.

The Wnt signaling pathway is an important regulator of cellular differentiation in a variety of cell types including osteoblasts. In this study, we investigated the impact of Wnt signaling on the function of human osteoblasts in relation to the stage of differentiation. Differentiating osteoblasts were created upon glucocorticoid (GC) treatment, whereas nondifferentiating osteoblasts were created by excluding GCs from the culture medium. GC-induced differentiation suppressed endogenous beta-catenin levels and transcriptional activity. During GC-induced osteoblast differentiation, activation of Wnt signaling slightly decreased alkaline phosphatase activity, but strongly suppressed matrix mineralization. In addition, mRNA expression of several Wnt signaling related genes was strongly regulated during GC-induced osteoblast differentiation, including frizzled homolog 8, dickkopf homolog 1, and secreted frizzled-related protein 1. In contrast, in the absence of GC-induced differentiation, Wnt signaling acted positively by stimulating basal alkaline phosphatase activity. Interestingly, pre-stimulation of Wnt signaling in early osteoblasts enhanced their differentiation capacity later on during the GC-induced differentiation process. In conclusion, we showed a differentiation-dependent effect of Wnt signaling on osteoblasts. Wnt signaling stimulated early osteoblasts in their capacity to differentiate, whereas mature osteoblasts were strongly inhibited in their capacity to induce mineralization. Moreover, osteoblast differentiation suppressed endogenous Wnt signaling and changed the expression of multiple Wnt signaling related genes.

Effect of virtual articulator settings on occlusal morphology of CAD/CAM restorations.

PURPOSE: Determinants of mandibular movements, like condylar inclination and incisal guidance, should be considered in the fabrication of restorations in occlusion to prevent posterior excursive occlusal interferences. The aim of this study was to investigate differences in the occlusal morphology of the right mandibular molar resulting from high, average, and low values of settings for determinants of anteroposterior and transverse mandibular movement using a virtual articulation model. MATERIAL AND METHODS: The articulation functionalities of computer integrated restorative technology by imaging and new acquisition (CYRTINA, Oratio B.V., Zwaag, The Netherlands) were used as a tool to examine the potential effect of determinants of mandibular movement on occlusal molar design. High, average, and low values for condylar guide inclination, incisal guide angle, and intercuspal contact area (antero-posterior determinants) and laterotrusion, mandibular lateral translation and intercuspal contact area (transverse determinants) were introduced and differences in molar morphology studied. The latter was done by comparing mesiodistal and buccolingual sections of the occlusal designs. These interocclusal differences were quantified as differences in frequency of occlusal distance intervals in an interocclusal range of 1 mm, measured from the occlusal surface of the molar model. The vertical distance with which a standard crown in occlusion had to be corrected to avoid interferences was calculated. RESULTS: Among all parameters, the ipsilateral and contralateral mandibular lateral translation, sagittal condylar guide inclination, the ipsilateral laterotrusion and the incisal guide angle give substantial occlusal surface corrections. The high setting for the ipsilateral mandibular lateral translation required most correction. CONCLUSION: High and low setting values of mandibular movement determinants require considerable adaptation of the occlusal surface of a crown to prevent occlusal disturbances.

A founder effect in three large Newfoundland families with a novel clinically variable spastic ataxia and supranuclear gaze palsy.

A distinctive slowly progressive neurodegenerative disorder, which falls under a new category of neurological diseases, the hereditary spastic ataxias (HSA), is described in three independently ascertained Newfoundland kindreds. HSA is a heterogeneous group of disorders in which pyramidal tract features overlap cerebellar characteristics. The families are assumed to have the same condition as, although apparently unrelated, all originate in a historically isolated cluster of rural communities and link to the same locus at 12p13, SAX1. Clinically the phenotype is very variable but lower limb hypertonicity and hyperreflexia are early and prominent generally preceded by eye movement abnormality, an impaired vertical downward saccade and a typical involuntary head jerk. These are followed by variable levels of ataxia, dysarthria, and dysphagia. Onset occurs in the first two decades and can be detected in most by early adulthood. Significant mobility problems are present by the fourth decade with a broad based ataxic and spastic gait. MRI scans of brain and spinal cord were normal. Neuropathology showed degeneration of corticospinal tracts and posterior columns and midbrain neuronal loss. The phenotype is striking in its diversity among and within families and the variability of expression can be observed within the same sibship. Pedigree analysis shows no evidence of anticipation or any sex differences in severity. The condition is unusually prevalent in the province of Newfoundland, which is characteristic of a founder effect followed by isolation and large family size. Fine mapping efforts have reduced the critical interval of the SAX1 locus to 1.9Mb. Identification of the SAX1 gene will help to clarify the pathogenesis of this type of HSA.

A locus for autosomal dominant hereditary spastic ataxia, SAX1, maps to chromosome 12p13.

The hereditary spastic ataxias (HSA) are a group of clinically heterogeneous neurodegenerative disorders characterized by lower-limb spasticity and generalized ataxia. HSA was diagnosed in three unrelated autosomal dominant families from Newfoundland, who presented mainly with severe leg spasticity, dysarthria, dysphagia, and ocular-movement abnormalities. A genomewide scan was performed on one family, and linkage to a novel locus for HSA on chromosome 12p13, which contains the as-yet-unidentified gene locus SAX1, was identified. Fine mapping confirmed linkage in the two large families, and the third, smaller family showed LOD scores suggestive of linkage. Haplotype construction by use of 13 polymorphic markers revealed that all three families share a disease haplotype, which key recombinants and overlapping haplotypes refine to about 5 cM, flanked by markers D12S93 and GATA151H05. SAX1 is the first locus mapped for autosomal dominant HSA.

Transcriptional regulation of human papillomavirus type 16 LCR by different C/EBPbeta isoforms.

During genital human papillomavirus (HPV) infection several cytokines are released, such as interleukin-1 (IL-1), tumor necrosis factoralpha (TNFalpha), IL-6, and IL-8. These cytokines may play a role in the immune surveillance against viral infection. Two of these cytokines, IL-1 and TNFalpha, suppress the transcription of the HPV16 early genes. CAATT/ enhancer binding protein, (C/EBPbeta), which is activated by IL-1 and TNFalpha, has been suggested to act as a mediator of this transcriptional downregulation. C/EBPbeta contains three different translation initiation sites that can lead probably by leaky ribosome scanning to the generation of three isoforms of C/EBPbeta, namely full-length C/EBPbeta, liver enriched transcriptional activator protein (LAP), and liver enriched inhibitory protein (LIP). When transiently expressed in C33A and HeLa cells, the first two C/EBPbeta isoforms activate the HPV16 long control region (LCR). LIP, which acts as an antagonist of C/EBPbeta, represses the HPV16 LCR activity. Our observation that treatment of HeLa cells with IL-1 leads to induction of LIP supports the hypothesis that the LCR downregulation by IL-1 is mediated by LIP.

Reduced binding activity of transcription factor NF-kappa B accounts for MHC class I repression in adenovirus type 12 E 1-transformed cells.

The early region 1 (E1) of human adenovirus (Ad) type 12 represses the expression of major histocompatibility (MHC) Class I genes in transformed primary rodent cells. In this paper we show that both NF-kappa B and KBF1 (p50 dimer) binding activity to the H2TF1 element in the Class I promoter is reduced in Ad12-13S-E1A-transformed cells compared to Ad5E1- or Ad12-12S-E1A-transformed cells. Consistently, in Ad12E1A-13S-transformed cells the H2TF1 element does not contribute to transcriptional activity in transient expression assays, whereas it does contribute in Ad12E1A-12S-transformed cells. Therefore, the most likely explanation is that reduced binding of NF-kappa B and KBF1 to the H2TF1 element accounts for the down-regulation of MHC Class I expression in Ad12E1- and Ad12E1A-13S-transformed cells.

Some epidemiological data on oral clefts in the northern Netherlands, 1981-1988.

Cleft lip with or without cleft palate [CL(P)] has a high prevalence [corrected] in the northern Netherlands. Several epidemiological parameters for oral clefts, including both CL(P) and cleft palate (CP), were analysed and compared with the literature. Except for the high prevalence at birth of isolated CL(P) no major differences in the pattern of occurrence described elsewhere were found. So far, descriptive epidemiological studies have not given any insight into the aetiology of this high CL(P) prevalence [corrected] in the Northern Netherlands. Therefore, case control studies on possible risk factors have been initiated.

Differential regulation of JunB and JunD by adenovirus type 5 and 12 E1A proteins.

The genes of the Jun family encode components of the TPA-inducible transcription factor AP-1. These genes are induced by a wide variety of extracellular stimuli, such as growth factors, phorbol esters and activators of protein kinase A. We have previously shown that the adenovirus type 5 E1A protein (E1A5) induces c-jun and junB expression in a number of different cell types. In this paper we show that the third member of the Jun family, junD, is also strongly induced by E1A5. Multiple sequences in the junB and junD promoters are responsible for the effects of E1A5. By contrast, adenovirus type 12 E1A (E1A12), like retinoic acid (RA), strongly induces c-jun expression, while expression of junB and junD is not altered. Interestingly, E1A12 expression leads to complete differentiation of P19 EC cells, comparable to the effect of RA on these cells, while E1A5-expressing cells are only partially differentiated.

Co-regulated expression of junB and MHC class I genes in adenovirus-transformed cells.

The expression of the junB gene parallels the expression of the MHC class I genes in Adenovirus (Ad) transformed cells. In Ad12E1-transformed primary BRK cells both genes are transcriptionally repressed only when the 13S product of Ad12E1A is present. This indicates that repression of MHC class I and junB genes is a function of conserved region 3 (CR3) of the Ad12E1A protein. In Ad5-transformed BRK cells expression of these genes is unchanged. In established NRK cells, however, introduction of Ad12E1A does not cause repression of the MHC class I and junB genes, but in these cells Ad5E1A increases the expression of both MHC class I and junB. Using mutant Ad5E1A genes, it is shown that this activation is mediated by CR1. Introduction of a functional junB gene under the control of a heterologous promoter in Ad12E1-transformed BRK cells causes no increase in MHC class I expression. This demonstrates that the down-regulation of junB is not directly responsible for class I repression, but rather that both genes are coregulated by the Ad12E1 region.

Differential effects of the adenovirus E1A oncogene on members of the AP-1 transcription factor family.

The adenovirus early region 1A (E1A) oncogene interferes with the expression level and activity of the AP-1 transcription factor family. E1A abolished the transactivating function of AP-1 (Jun/Fos), which binds to the 12-O-tetradecanoylphorbol-13-acetate-responsive element of the collagenase gene (collTRE). In contrast, the activity of another member of the AP-1 family that binds to the c-junTRE was not repressed. The mRNA expression of the c-jun gene was, in fact, strongly elevated in various cell types expressing the E1A gene of either adenovirus type 5 (Ad5) or Ad12. The regulation of the junB gene by adenovirus E1A, on the other hand, depended both on the cell type and on the transforming adenovirus serotype. The fact that E1A-induced alterations in the repertoire of AP-1 transcription factors depend on its transforming domain in conserved region 1 suggests that the effects are relevant for the transformation process.

Adenovirus type 12 E1A down regulates expression of a transgene under control of a major histocompatibility complex class I promoter: evidence for transcriptional control.

The E1 region of human adenovirus type 12 (Ad12 E1) represses the expression of major histocompatibility complex (MHC) class I genes in transformed primary rodent cells. Conflicting results have been reported as to whether this E1A-mediated repression occurs at a transcriptional or a posttranscriptional level. In the present study, we show that in Ad12 E1-transformed primary baby mouse kidney cells from transgenic mice harboring the human growth hormone gene under control of an H-2K promoter both the expression of the endogenous MHC class I genes and the expression of the transgene are repressed. This experiment, as well as nuclear run-on analyses performed with single-stranded probes, revealed that Ad12 E1A inhibits MHC class I gene expression by repressing its promoter.

Isolation, expression, and the primary structure of HLA-Cw1 and HLA-Cw2 genes: evolutionary aspects.

The HLA-Cw1 and -Cw2 genes were identified in a genomic library and their products characterized by biochemical methods. The HLA-Cw1 and -Cw2 genes, upon transfection in mouse L cells, give rise to class I antigen heavy chains that associate with neither mouse nor human beta-2 microglobulin. They are indistinguishable in isoelectric point from polypeptides identified as HLA-Cw1 and -Cw2 in human cells. The nucleotide sequence of HLA-Cw1 and -Cw2 and their comparison with HLA-Cw3, the only other known HLA-C sequence, reveal a characteristic pattern of locus-specific amino acids. A comparison of 13 different human class I primary structures leads us to speculate that the most variable region in HLA class I antigens, positions 61-83, could assume an alpha helical structure of critical importance for class I antigen function. The locus specificity and the higher degree of intralocus conservation in the COOH-terminal region, especially in the transmembrane and cytoplasmic domains, must reflect evolutionary ancestry rather than positive selection. In view of the pattern and types of substitutions observed for HLA-C locus products, their function as immune response gene products is questioned.