The spectrum of pathogenic mutations in SPINK5 in 19 families with Netherton syndrome: implications for mutation detection and first case of prenatal diagnosis.

The Comèl-Netherton syndrome is an autosomal recessive multisystemic disorder characterized by localized or generalized congenital ichthyosis, hair shaft abnormalities, immune deficiency, and markedly elevated IgE levels. Life-threatening complications during infancy include temperature and electrolyte imbalance, recurrent infections, and failure to thrive. To study the clinical presentations of the Comèl-Netherton syndrome and its molecular cause, we ascertained 19 unrelated families of various ethnic backgrounds. Results of initial linkage studies mapped the Comèl-Netherton syndrome in 12 multiplex families to a 12 cM interval on 5q32, thus confirming genetic homogeneity of Comèl-Netherton syndrome across families of different origins. The Comèl-Netherton syndrome region harbors the SPINK5 gene, which encodes a multidomain serine protease inhibitor (LEKTI) predominantly expressed in epithelial and lymphoid tissues. Recently, recessive mutations in SPINK5 were identified in several Comèl-Netherton syndrome patients from consanguineous families. We used heteroduplex analysis followed by direct DNA sequencing to screen all 33 exons and flanking intronic sequences of SPINK5 in the affected individuals of our cohort. Mutation analysis revealed 17 distinct mutations, 15 of which were novel, segregating in 14 Comèl-Netherton syndrome families. The nucleotide changes included four non-sense mutations, eight small deletions or insertions leading to frameshift, and five splice site defects, all of which are expected to result in premature terminated or altered translation of SPINK5. Almost half of the mutations clustered between exons 2 and 8, including two recurrent mutations. Genotype-phenotype correlations suggested that homozygous nucleotide changes resulting in early truncation of LEKT1 are associated with a severe phenotype. For the first time, we used molecular data to perform prenatal testing, thus demonstrating the feasibility of molecular diagnosis in the Comèl-Netherton syndrome.

Interleukin-1beta upregulates MMP-9 expression in stromal cells of human giant cell tumor of bone.

Giant cell tumor (GCT) of bone is a progressive, potentially malignant process that destroys skeletal tissue. It consists of multinucleated giant cells, which are hypothesized to be derived from a monocyte/macrophage lineage and mononuclear stromal cells, and the precise relationship of these cells is not fully understood. Recently, we demonstrated that the production of matrix metalloproteinase-9 (MMP-9) in GCT stromal cells is regulated by certain factor(s) secreted by the multinucleated giant cells. In the present study, we evaluated for the presence of interleukin-1beta (IL-1beta) and attempted to establish its possible role for the induction of MMP-9 in GCT stromal cells. Using enzyme-linked immunosorbent assay (ELISA), we have demonstrated that the primary GCT cultures secrete both IL-1beta and MMP-9. The addition of monoclonal antibody (mAb) against IL-1beta partially abrogated, but did not abolish, MMP-9 expression. Our results on gelatin zymography, reverse transcriptase-polymerase chain reaction (RT-PCR), and immunofluorescence showed that GCT stromal cells did not express MMP-9, although treatment with IL-1beta induced MMP-9 expression in a dose-dependent manner, and the secretion peaked 24 h after stimulation and then plateaued. Studies with cycloheximide, a protein synthesis inhibitor, demonstrated that de novo protein synthesis is required for IL-1beta induced MMP-9 expression. Moreover, nuclear run-on analysis has revealed that IL-1beta significantly increased MMP-9 gene transcription in GCT stromal cells. The data suggest that IL-1beta secreted by the multinucleated giant cells in GCT may be one of the factors responsible for the induction of MMP-9 at the transcriptional level in GCT stromal cells in vivo. We conclude that GCT has a self-stimulatory system for the production of MMP-9, and the ability of stromal cells to produce MMP-9 with appropriate stimuli, such as IL-1beta, and possibly in concert with other cytokines may contribute to the aggressive and potentially malignant behavior of GCT.

Expression of 72 kDa and 92 kDa type IV collagenases from human giant-cell tumor of bone.

Basement membrane forms widespread barriers to tumor invasion. It has been shown that tumor-secreted, basement membrane-degrading enzymes, namely metalloproteinases (MMPs) play an important role in tumor invasion and metastasis. In this study, we determined the enzymatic activity, content, and mRNA of both the 72 kDa (MMP-2) and 92 kDa (MMP-9) MMPs in primary cultures of human giant-cell tumor of bone (GCT) in vitro and in tissue extracts (in vivo). Gelatin zymography showed the presence of lytic bands at M(r) 121,000, 92,000, and 72,000, and these enzymatic activities were inhibited by EDTA, an inhibitor of MMPs. Western blots with antibodies specific for MMP-2 and MMP-9 confirmed the presence of MMP-2 and MMP-9 both in vitro and in vivo, but GCT cells at late passage showed only MMP-2. Northern blots using labeled cDNA probes specific for these molecules revealed the presence of 3.1 kb transcript for MMP-2 and a 2.9 kb transcript for MMP-9. Using specific antibodies to 72 kDa and 92 kDa type IV collagenases, we studied their cellular distribution by immunohistochemical means. Stronger immunoreactivity was found for 92 kDa type IV collagenase than 72 kDa type IV collagenase in the giant cells. It appears, therefore, that MMP-9 may play an important role in the malignant behavior of GCTs and suggests a potential therapeutic role for protease inhibitors in attempting to minimize the invasive behavior of GCTs.

Regulation of MMP-9 (92 kDa type IV collagenase/gelatinase B) expression in stromal cells of human giant cell tumor of bone.

Matrix metalloproteinases (MMPs) play an important regulatory role in tissue morphogenesis, cell differentiation, tumor invasion and metastasis. Several authors have reported a direct correlation between the production of 72 kDa (MMP-2) and 92 kDa (MMP-9) type IV collagenases/gelatinases and the metastatic potential of cancer cells. Recently, we have identified the expression of both MMP-2 and MMP-9 in primary cultures of human giant cell tumor (GCT) of bone in vitro, and in tissue extracts in vivo. Interestingly, MMP-9 is not secreted by late-passaged GCT cells. It is possible that the production of MMP-9 is regulated by certain factor(s) secreted by the multinucleated giant cells in the primary culture. In order to test this hypothesis, the effect of primary-culture-conditioned medium on the expression of MMP-9 by late-passaged mononuclear stromal cells was examined. Adding conditioned medium from the primary GCT culture to the late-passaged stromal cells induced MMP-9, as evidenced by the presence of lytic bands at M(r) 92,000 and 72,000 on a gelatin zymogram. These enzyme activities were inhibited by EDTA, a well-known inhibitor of the MMPs. We confirmed these results by Western blotting using specific antibodies and RT-PCR for MMP-2 and MMP-9. Immunofluorescence studies with specific antibodies to MMP-9 further confirmed its expression by the passaged stromal cells cultured in the primary-culture-conditioned medium. The data indicate that MMP-2 and MMP-9 are produced by the mononuclear stromal cells when cultured in GCT primary-culture-conditioned medium. This suggests that multinucleated giant cells in primary cultures secrete a factor(s) that stimulates stromal cells to produce MMP-9, which, in turn, may contribute to the aggressive behavior of GCT.

Clinical and experimental studies linking oxidative metabolism to phenytoin-induced teratogenesis.

The research presented in this article concerns the proposed mechanism of phenytoin-induced teratogenicity that focuses on oxidative metabolites as sources of reactive species in clinical studies and by testing paradigms in animal models. The clinical aspect involved determining whether at-risk fetuses could be detected prenatally on the basis of low or deficient epoxide hydrolase activity. In 19 pregnancies monitored by amniocentesis, we predicted an adverse outcome in four infants on the basis of low enzyme activity. When examined neonatally, all four infants had the dysmorphic features of the "fetal hydantoin syndrome." In an animal model of phenytoin-induced teratogenesis, the level of fetal exposure to oxidative metabolites was decreased by coadministration of the cytochrome P-450-inhibiting antiepileptic drug stiripentol, which significantly reduced the incidence of phenytoin-induced congenital malformations in two of the three inbred mouse strains, thus providing support for the hypothesis that oxidative metabolites are critical in mediating phenytoin teratogenesis.

Wiedemann-Beckwith syndrome in apparently discordant monozygotic twins.

We report 3 pairs of monozygotic (MZ) twins, one twin showing typical Wiedemann-Beckwith syndrome (WBS) with minimal or no expression of the condition in the co-twin. These cases are documented, and three previously reported MZ twin pairs are reviewed. Phenotypic concordance for this syndrome in MZ twin pairs has not been reported. Many cases of familial occurrence have been published and different modes of inheritance have been postulated. Based on the twin-twin variability seen in our patients, it seems the most likely mechanism of inheritance is an autosomal dominant mutation with environmental modification of expressivity, or reduced phenotrance.

Pregnancy in a woman with the Brachmann-de Lange syndrome.

We present the first reported pregnancy in a woman with the Brachmann-de Lange syndrome. This 24-year-old primagravid woman was originally seen at 13 weeks of pregnancy with manifestations consistent with this diagnosis. High-resolution chromosome studies, performed on lymphocytes, showed a normal 46,XX chromosome constitution. Because of the stage of pregnancy at which she presented, a genetic amniocentesis was simultaneously performed for chromosome analysis on the fetal cells, which were also normal (46,XX). The uncomplicated pregnancy was monitored carefully and at 37 1/2 weeks of gestation she delivered a clinically normal-appearing female infant.

Partial duplication of distal 17q.

A male propositus and an older sister had a similar pattern of congenital anomalies, including facial asymmetry with hypertelorism, frontal bossing and temporal narrowness, a broad nasal bridge, epicanthal folds, a wide mouth with a thin upper lip, micrognathia, webbed neck, low-set posteriorly angulated ears, and an abnormal hairline. There was also postaxial polydactyly, flexion contractures of the digits, hypotonia, and a congenital heart anomaly. The propositus also had renal anomalies whereas the sister did not, and the sister had a cleft lip and palate not present in her brother. The propositus and a subsequent fetus identified through genetic amniocentesis were determined to have a 46, XY, -18, +der(18),t(17;18)(q25.1;q23)mat chromosome constitution. Clinical findings are compared to those of other reported cases of dup(17q).

Partial deletion of distal 17q.

A newborn female was found to have a deletion of the terminal portion of 17q. Prominent manifestations included microcephaly, apparent hypertelorism, epicanthic folds, a broad nasal bridge with anteverted nostrils, posteriorly angulated ears, micrognathia, widely spaced nipples, arachnodactyly with proximal thumbs, and a coxa vara deformity. The unbalanced translocation was inherited from the mother, who had a reciprocal translocation involving the terminal portions of 2p and 17q. To the best of our knowledge, this is the first report of a liveborn infant with deletion of the distal portion of 17q with the exception of reports of patients with ring chromosome 17.

The neuroimaging findings in Sotos syndrome.

We reviewed the neuroimaging studies of 40 patients with classic Sotos syndrome. The studies consisted of CT scans only in 4 patients and one or more MRI scans in 36 patients. The diagnosis of Sotos syndrome was made using well-established clinical criteria. The neuroimaging studies of each patient were evaluated subjectively by visual inspection and the chief findings were tabulated and grouped into five categories: 1) ventricular abnormalities, 2) extracerebral fluid spaces, 3) midline abnormalities, 4) migrational abnormalities, and 5) others. The most common abnormality of the cerebral ventricles was prominence of the trigone (90%), followed by prominence of the occipital horns (75%) and ventriculomegaly (63%). The supratentorial extracerebral fluid spaces were increased for age in 70% of the patients and the fluid spaces in the posterior fossa were increased in 70% also. A variety of midline abnormalities were noted but anomalies of the corpus callosum were almost universal. Gray matter heterotopias occurred in only 3 (8%) of 36 patients. Periventricular leukomalacia, presumably the result of prenatal or perinatal difficulties and unrelated to the basic condition, was the most common of the miscellaneous other abnormalities noted. The neuroimaging findings of Sotos syndrome are distinct enough to allow differentiation of this syndrome from other mental retardation syndromes with macrocephaly.

Familial inverted duplication 7p.

A 10-month-old female with developmental delay and failure to thrive was referred for genetic evaluation as part of an adoption assessment. Physical exam showed a mildly beaked nose and clinodactyly, but otherwise nothing remarkable. Chromosome analysis showed an inverted duplication of the p12.2-->p13 portion of chromosome 7[(46,XX, dup(7)(p13p12.2)]. The proposita's older brother, mother, and grandmother were cognitively delayed and had the same chromosome 7 duplication. A review of the literature showed no other cases involving this exact duplication.

Transcriptional regulation of MMP-9 expression in stromal cells of human giant cell tumor of bone by tumor necrosis factor-alpha.

We determined whether certain factor(s) secreted by multinucleated giant cells, which is of monocyte/macrophage lineage in giant cell tumor of bone (GCT), regulate the induction of matrix metalloproteinase (MMP)-9 expression in mononucleated stromal cells. Our data derived using enzyme linked immunosorbant assays (ELISAs) suggest that the GCT cells in primary culture produce both MMP-9 and tumor necrosis factor-alpha (TNF-alpha). Further, the MMP-9 expression in GCT primary cultures was partially abrogated by neutralizing antibody to TNF-alpha, suggesting that TNF-alpha secretion by the multinucleated giant cells may be one of the factors responsible for the production of MMP-9 by the stromal cells in vivo. In order to confirm this we examined the role of TNF-alpha on the induction of MMP-9 expression in bone GCT stromal cells. These cells express MMP-2, but not MMP-9. However, treatment of these cells with TNF-alpha induced the expression of MMP-9 in a concentration-dependent manner. Kinetic experiments revealed that the secretion of MMP-9 peaked 12 h post TNF-alpha stimulation. Immunofluorescence studies confirmed the expression of MMP-9 after stimulation of GCT stromal cells with TNF-alpha. Further, TNF-alpha-induced MMP-9 expression was completely blocked with neutralizing antibody to TNF-alpha, thereby demonstrating the specificity. In addition, the induction of MMP-9 expression by TNF-alpha was completely abrogated in the presence of cycloheximide, a protein synthesis inhibitor, suggesting that de novo protein synthesis may be required. Nuclear run-on analysis demonstrated that treatment of GCT stromal cells significantly enhanced the MMP-9 gene transcription. Together, our data suggest that TNF-alpha secreted by the multinucleated giant cells up-regulates MMP-9 expression in GCT stromal cells by the induction of certain transcription factors, which in turn enhanced the rate of transcription of MMP-9 gene. These studies also suggest the existence of an essential cell-cell interaction in the regulation of MMP-9 expression in GCT.

Accelerated linear growth and advanced bone age in Sotos syndrome is not associated with abnormalities of collagen metabolism.

OBJECTIVES: To investigate whether the advanced bone age in Sotos syndrome is associated with alterations in type I collagen metabolism in bone. DESIGN AND METHODS: The metabolism of collagen was studied by analyzing the production, gene expression and degradation of type I collagen in dermal fibroblast strains from patients with Sotos syndrome and comparing them with fibroblasts from age-matched healthy subjects. Collagen production was determined as collagenase digestible radioactivity and collagen mRNA levels were measured by RT-PCR. Collagen degradation was assessed by specific collagenase assay and gelatin zymography. To determine the structural defects in type I collagen, the newly synthesized proteins were analyzed by SDS-PAGE before and after proteolytic digestion with pepsin. RESULTS: In the present study, we have demonstrated that the collagen production, secretion and degradation in Sotos syndrome is comparable to controls. In addition, no qualitative differences in mRNA transcripts for type I collagen were detected between the control and Sotos syndrome fibroblasts. The secretion and intracellular accumulation of procollagen is also comparable to controls. The analysis of both procollagen and collagen on SDS-PAGE did not exhibit any major structural changes as compared with controls. CONCLUSIONS: Our results on several aspects of collagen metabolism have demonstrated for the first time that collagen, the most abundant of mammalian proteins and the major constituent of bone, is normal in patients with Sotos syndrome. Therefore, it appears that the advanced bone age and accelerated linear growth seen in patients with Sotos syndrome may not be attributed to inherent abnormalities of collagen metabolism. The etiology and the pathogenesis of Sotos syndrome still remains unclear.

Teratogenic potential of cocaine.

Cocaine has been implicated as a potential cause of congenital abnormalities since the mid 1980s. Clinical studies have reported an increased risk of cardiovascular and central nervous system abnormalities as well as an increased incidence of limb reduction defects and intestinal atresias. The published data have not established an unequivocal link between cocaine and these abnormalities. The most compelling evidence for the role of cocaine as a teratogen is the increased risk of genitourinary tract defects. Although animal models have also yielded contradictory conclusions, it is intriguing to note that the abnormalities observed in these models are similar to those seen clinically. This review summarizes the clinical and basic research relating to the teratogenic potential of cocaine.

Biochemical and molecular teratology of fetal hydantoin syndrome.

Animal and human research has clearly shown that anticonvulsants are teratogens and pose a risk for fetal malformations. In the case of dilantin it appears that fetal susceptibility correlates with the fetal level of the microsomal detoxifying enzyme epoxide hydrolase. The genetics of seizures in the parents does not predict the risk for fetal teratogenesis. The clinician must work with a mother who has seizures prior to conception to achieve the best control of seizures with a single anticonvulsant at the lowest effective dose to minimize the teratogenic potential, but even if this is done there is still a risk of fetal malformations and developmental delays. Each pregnancy in a woman on anticonvulsants is at risk, and appropriate counseling should be accomplished before conception so the family can make an informed decision. The exact risk of teratogenesis is lower than previously recorded. Dilantin poses approximately a 10% risk, tegretol less than 10%, and valproic acid causes a threefold increase in the risk of neural tube defects as well as an increased risk of other malformations. The positive aspect is that with good medical management and good prenatal care approximately 90% of infants exposed to anticonvulsants in utero will not show evidence of teratogenesis. Finally, it is important to stress that all pregnancies carry a 3% risk for a major birth defect independent of any exposures or genetic history.

Evaluation of the precision and accuracy of an automated sample introduction accessory for the flame atomic absorption spectrometric measurement of calcium in serum.

The measurement precision and accuracy that results from the use of a sample introduction peristaltic pump system for automated instrument calibration and analysis is compared to manual methods based on traditional gravimetric and volumetric dilution procedures for flame atomic absorption analyses in water and serum matrices. Whilst use of the automated system improves speed of analysis, measurement precision was found to be approximately 2-fold worse than the manual methods based on gravimetric and volumetric dilution procedures.

Hereditary disorders of albumin synthesis.

Albumin, the major serum protein, is considered to be responsible for maintenance of normal serum colloid osmotic pressure, transport of certain hormones and maintaining an endogenous source of amino acids. The acute loss of albumin in the nephrotic syndrome leads to severe generalized peripheral edema and difficulties in maintenance of normal blood pressure as well as hypocalcemia. Yet, there are now 14 reported cases of congenital analbuminemia in which serum albumin is absent or greatly reduced without clinical evidence of edema, decreased hormone levels or abnormal amino acid requirements. These "experiments of nature" are reviewed in detail comparing clinical and laboratory findings in these patients with the postulated effects of a low serum albumin level.

Hematologic aberrations in metabolic diseases.

This study of enzyme deficiencies and hematologic aberrations in metabolic diseases includes disorders of amino acidopathies, lipid disease, albinism, carbohydrates, and mucopolysaccharidosis.

Inherited disorders of amino acid transport in relation to the kidney.

Cystinuria was first described in 1810. Since the initial description, a group of renal cellular transport deficit diseases has been characterized. The study of genetic diseases that create a specific aminoaciduria has expanded our knowledge of cellular structure, cellular transport, and intracellular concentration gradients. A review of the theories and experimental data obtained through investigations of the renal aminoacidurias are presented.