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PubMed1995

Idiopathic generalized epilepsy of adolescence: are the syndromes clinically distinct?

Juvenile myoclonic epilepsy, juvenile absence epilepsy, and epilepsy with generalized tonic-clonic seizures (GTCS) on awakening are the three syndromes of idiopathic generalized epilepsy of adolescent onset currently included in the classification of epilepsy syndromes of the International League Against Epilepsy (ILAE). Although they differ in their predominant seizure types, the syndromes share several clinical features, thus giving rise to questions of phenotypic overlap and purity. We studied the clinical features of 101 patients with idiopathic generalized epilepsy beginning in adolescence. A standardized interview was used to elucidate seizure phenomenology, precipitants, frequency, and response to treatment. Groups defined by seizure type were compared and their similarities examined. The group with myoclonic but not absence seizures (21 patients) corresponded to the ILAE syndrome of juvenile myoclonic epilepsy, whereas those with absences but not myoclonus (37 patients) resembled juvenile absence epilepsy. Twenty-six patients shared the features of juvenile myoclonic epilepsy and juvenile absence epilepsy. Epilepsy with GTCS on awakening was not a specific syndromic entity; 10 patients had this seizure type alone. Seven patients were without a syndromic diagnosis. In these patients only GTCS occurred, but neither on awakening nor in the evening period of relaxation. We conclude that whilst syndromes of idiopathic generalized epilepsy of adolescence can be recognized, the current classification does not include all patients. In addition, the boundaries between the syndromes are indistinct, suggesting underlying neurobiological, possibly genetic, relationships.

Adolescent↗
PubMed1996

Schwannomatosis: a clinical and pathologic study.

Schwannomas are benign nerve sheath tumors that most commonly occur singularly in otherwise normal individuals. Multiple schwannomas in a single patient are most often seen in neurofibromatosis 2 (NF2), but several recent reports suggest that schwannomatosis may also be a distinct clinical entity. We studied the clinical, radiographic, and pathologic features of 14 patients with multiple schwannomas who did not have vestibular schwannoma diagnostic of NF2. Most patients had peripheral nerve tumors that presented with pain. Many also had spinal nerve root and cranial nerve tumors. Three had multiple tumors limited to a single limb. We found that these 14 individuals did not exhibit phenotypic overlap with the neurofibromatoses. Only 1 of 14 patients had a positive family history. We conclude that patients with multiple schwannomas, who do not have vestibular schwannoma, comprise a distinct clinical problem, but further molecular genetic analysis is needed to define the pathophysiology of this disorder.

Adolescent↗
PubMed2006

Contribution of genetic factors to the pathogenesis of Paget's disease of bone and related disorders.

Paget's disease of bone (PDB) is a common condition with a strong genetic component that is characterized by focal increases in bone turnover, leading to bone deformity, pathological fractures, and various other complications. Several rare disorders have also been described that show phenotypic overlap with PDB. Genome-wide searches have identified several susceptibility loci for PDB and PDB-like disorders, and mutations that cause these disorders have now been identified in four genes, all of which are involved in the RANK-NF-kappaB signaling pathway. Mutations in SQSTM1, which encodes an important scaffold protein in this pathway, have been found to be a common cause of classical PDB. Thus far, all disease-causing mutations in SQSTM1 affect the ubiquitin-associated (UBA) domain of the gene product and cause loss of ubiquitin binding. The rare PDB-like disorders of familial expansile osteolysis, early-onset familial PDB, and expansile skeletal hyperphosphatasia are caused by duplication mutations in exon 1 of the TNFRSF11A gene, which encodes the RANK receptor. This gene does not seem to be involved in the pathogenesis of classical PDB. Inactivating mutations in the TNFRSF11B gene, which encodes osteoprotegerin, cause juvenile PDB, and TNFRSF11B polymorphisms seem to increase the risk of classical PDB. The rare syndrome of hereditary inclusion body myopathy, PDB, and frontotemporal dementia (IBMPFD) is caused by mutations in the VCP gene, which is involved in regulating I-kappaB degradation by the proteasome. The disease-causing mutations in VCP cluster in and around a domain involved in ubiquitin binding. Whereas SQSTM1 has emerged as an important gene for classical PDB, most kindreds with familial PDB do not carry SQSTM1 mutations, indicating that additional genes for PDB remain to be discovered. In light of the molecular defects that have been identified thus far, it seems likely that these genes will also be involved in the RANK-NF-kappaB signaling pathway or its interactions with the ubiquitin-proteasome system.

Genetic Predisposition to Disease↗
PubMed2006

Adaptive stress response in segmental progeria resembles long-lived dwarfism and calorie restriction in mice.

How congenital defects causing genome instability can result in the pleiotropic symptoms reminiscent of aging but in a segmental and accelerated fashion remains largely unknown. Most segmental progerias are associated with accelerated fibroblast senescence, suggesting that cellular senescence is a likely contributing mechanism. Contrary to expectations, neither accelerated senescence nor acute oxidative stress hypersensitivity was detected in primary fibroblast or erythroblast cultures from multiple progeroid mouse models for defects in the nucleotide excision DNA repair pathway, which share premature aging features including postnatal growth retardation, cerebellar ataxia, and death before weaning. Instead, we report a prominent phenotypic overlap with long-lived dwarfism and calorie restriction during postnatal development (2 wk of age), including reduced size, reduced body temperature, hypoglycemia, and perturbation of the growth hormone/insulin-like growth factor 1 neuroendocrine axis. These symptoms were also present at 2 wk of age in a novel progeroid nucleotide excision repair-deficient mouse model (XPD(G602D/R722W)/XPA(-/-)) that survived weaning with high penetrance. However, despite persistent cachectic dwarfism, blood glucose and serum insulin-like growth factor 1 levels returned to normal by 10 wk, with hypoglycemia reappearing near premature death at 5 mo of age. These data strongly suggest changes in energy metabolism as part of an adaptive response during the stressful period of postnatal growth. Interestingly, a similar perturbation of the postnatal growth axis was not detected in another progeroid mouse model, the double-strand DNA break repair deficient Ku80(-/-) mouse. Specific (but not all) types of genome instability may thus engage a conserved response to stress that evolved to cope with environmental pressures such as food shortage.

Aging↗
PubMed2006

Ataxia-telangiectasia and related diseases.

Appropriate cellular signaling responses to DNA damage and the ability to repair DNA are fundamental processes that are required for organismal survival. Ataxia-telangiectasia (A-T) is a rare neurodegenerative disease that results from defective DNA damage signaling. Understanding the molecular basis of A-T has provided many critical insights into the cellular response to DNA double-strand breaks (DSBs). A-T is a syndrome that shows pronounced neurodegeneration of the nervous system coincident with immune deficiency, radiosensitivity, and cancer proneness. A-T results from inactivation of the A-T mutated (ATM) kinase, a critical protein kinase that regulates the response to DNA-DSBs by selective phosphorylation of a variety of substrates. Therefore, understanding the ATM signaling program has important biological ramifications for nervous system homeostasis. Underscoring the importance of the DNA-DSBs response in the nervous system are other diseases related to A-T that also result from defects in this signaling pathway. In particular, defects in the DNA damage sensor, the Mre11-RAD50-NBS1 complex, also lead to syndromes with neurological deficits and overlapping phenotypes to A-T. Collectively, these diseases highlight the critical importance of appropriate responses to DNA-DSBs to maintain homeostasis in the nervous system.

Animals↗
PubMed2006

BIR-1, the homologue of human Survivin, regulates expression of developmentally active collagen genes in C. elegans.

BIR-1 and Survivin are highly conserved members of the inhibitor of apoptosis protein family that regulate cell division in nematodes and mammals and inhibit apoptosis in mammals. In the C. elegans genome, bir-1 is organized in an operon together with transcription and splicing cofactor CeSKIP (skp-1) and is highly expressed during embryogenesis as well as in non-dividing cells during larval development. Previously we have shown that BIR-1 regulates transcription and development and its loss-of-function phenotype overlaps with loss of function of CeSKIP and nuclear hormone receptor CHR3 (NHR-23). Here we searched for genes whose expression is affected by BIR-1 loss of function using whole-genome microarray experiments and identified several collagen genes as candidate targets of bir-1 inhibition in L1 larval stage. The decreased expression of selected collagen genes in bir-l-inhibited larvae was confirmed by quantitative RT-PCR. Next, we generated transgenic lines expressing bir-1 mRNA under a heat shock-regulated promoter and tested whether bir-1 overexpression has the potential to augment the expression of genes that showed decreased expression in worms treated with bir-1 RNAi. Overexpression of bir-1 resulted in a pronounced increase (2 to 5 times) of the expression of these genes. Our findings support the concept that BIR-1, a protein generally regarded as a mitotic factor, is involved in the regulation of transcription during normal development of C. elegans and has a strong ability to affect transcription of developmentally active genes if overexpressed.

Animals↗
PubMed2006

High levels of Cre expression in neuronal progenitors cause defects in brain development leading to microencephaly and hydrocephaly.

Hydrocephalus is a common and variegated pathology often emerging in newborn children after genotoxic insults during pregnancy (Hicks and D'Amato, 1980). Cre recombinase is known to have possible toxic effects that can compromise normal cell cycle and survival. Here we show, by using three independent nestin Cre transgenic lines, that high levels of Cre recombinase expression into the nucleus of neuronal progenitors can compromise normal brain development. The transgenics analyzed are the nestin Cre Balancer (Bal1) line, expressing the Cre recombinase with a nuclear localization signal, and two nestin CreER(T2) (Cre recombinase fused with a truncated estrogen receptor) mice lines with different levels of expression of a hybrid CreER(T2) recombinase that translocates into the nucleus after tamoxifen treatment. All homozygous Bal1 nestin Cre embryos displayed reduced neuronal proliferation, increased aneuploidy and cell death, as well as defects in ependymal lining and lamination of the cortex, leading to microencephaly and to a form of communicating hydrocephalus. An essentially overlapping phenotype was observed in the two nestin CreER(T2) transgenic lines after tamoxifen mediated-CreER(T2) translocation into the nucleus. Neither tamoxifen-treated wild-type nor nestin CreER(T2) oil-treated control mice displayed these defects. These results indicate that some forms of hydrocephalus may derive from a defect in neuronal precursors proliferation. Furthermore, they underscore the potential risks for developmental studies of high levels of nuclear Cre in neurogenic cells.

Aneuploidy↗
PubMed2003

Cytokines in the pathogenesis of chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a common cause of morbidity and mortality. The term is heterogenous and encompasses a number of distinct but often overlapping phenotypes including chronic bronchitis, small airways obstruction, emphysema and in some individuals, a systemic component. Although there have been significant advances in understanding the pathophysiology of COPD, understanding of the role of the inflammation in the pathogenesis of the condition remains in its infancy. Indeed, cytokines that are known to orchestrate the inflammatory response in asthma and other inflammatory diseases are only beginning to be reported in COPD. In this review, we highlight the potential role of cytokines in the development of mucus hypersecretion observed in chronic bronchitis and the morphological changes observed in the small airways and airspaces contributing to the development of airflow limitation and respiratory failure respectively. We report evidence that exacerbations are linked to increased expression of pro-inflammatory cytokines and that the wasting and skeletal muscle dysfunction observed in some patients is most probably related to the presence of a systemic inflammatory response. In addition transgenic and gene therapy technology has been used to explore the temporal and co-ordinated role of cytokines in the development of COPD animal models. Enhanced understanding of the events involved in the pathogenesis of COPD will lead to the development of therapy with potential to modify the observed progressive decline in lung function and impact on the development of the illness.

Animals↗
PubMed2006

Variation within the gene encoding the upstream stimulatory factor 1 does not influence susceptibility to type 2 diabetes in samples from populations with replicated evidence of linkage to chromosome 1q.

The gene encoding the transcription factor upstream stimulatory factor (USF)1 influences susceptibility to familial combined hyperlipidemia (FCHL) and triglyceride levels. Phenotypic overlap between FCHL and type 2 diabetes makes USF1 a compelling positional candidate for the widely replicated type 2 diabetes linkage signal on chromosome 1q. We typed 22 variants in the F11R/USF1 region (1 per 3 kb), including those previously implicated in FCHL-susceptibility (or proxies thereof) in 3,726 samples preferentially enriched for 1q linkage. We also examined glucose- and lipid-related continuous traits in an overlapping set of 1,215 subjects of European descent. There was no convincing evidence for association with type 2 diabetes in any of seven case-control comparisons, individually or combined. Family-based association analyses in 832 Pima subjects were similarly negative. At rs3737787 (the variant most strongly associated with FCHL), the combined odds ratio, per copy of the rarer A-allele, was 1.10 (95% CI 0.97-1.24, P = 0.13). In 124 Utah subjects, rs3737787 was significantly associated (P = 0.002) with triglyceride levels, but direction of this association was opposite to previous reports, and there was no corroboration in three other samples. These data exclude USF1 as a major contributor to type 2 diabetes susceptibility and the basis for the chromosome 1q linkage. They reveal only limited evidence for replication of USF1 effects on continuous metabolic traits.

Adult↗
PubMed1997

Diabetes associated with a novel 3264 mitochondrial tRNA(Leu)(UUR) mutation.

OBJECTIVE: To present a novel mitochondrial DNA mutation in a diabetic family RESEARCH DESIGN AND METHODS: The proband was a 64-year-old man. In the family, diabetes was maternally inherited. He had diabetes, cerebellar ataxia, cervical lipoma, hearing loss, olfactory dysfunction, ophthalmoplegia, and facial nerve bilateral palsy. On examination, early insulin secretion was blunted, and the M value on glucose clamp test was low. In muscle, ragged red fibers were not found. T-to-C mutation at position 3264 was detected in the proband (0.5% mutant DNAs in leukocyte and 30% in muscle), but was not detected in 201 normal individuals. RESULTS: Heteroplasmy of mutation, maternal inheritance of diabetes, and symptoms related to mitochondrial dysfunction suggest the pathogenecity of this 3264 mutation. As for diabetes etiology, both impaired insulin secretion and decreased insulin sensitivity seem to be important. In phenotypic characteristics, the combination of cerebellar ataxia and lipoma is a symptom sometimes found in myoclonic epilepsy and ragged red fibers (MERRFs). Ophthamoplegia is a symptom of chronic progressive external ophthalmoplegia (CPEO). These suggest that our proband had phenotypic overlap with MERRF and CPEO. Conversely, facial nerve bilateral palsy is a rare finding. The pictures that focused on his cranial nerves were thus unique, suggesting the heterogeneity of mitochondrial DNA (mtDNA)-related diabetes. CONCLUSIONS: A novel 3264 mitochondrial DNA mutation in diabetes gives new insight to the etiology of mitochondrial diabetes. Its pathogenecity supports the belief that the tRNA(Leu)(UUR) gene is an etiological hot spot of mitochondrial diseases.

DNA, Mitochondrial↗
PubMed2006

Mutation screening in juvenile polyposis syndrome.

Juvenile polyposis syndrome (JPS) is an autosomal dominant cancer predisposition syndrome characterized by congenital anomalies, hamartomatous polyps in the gastrointestinal tract, and the development of tumors in these tissues. The diagnosis of JPS is often difficult because of the phenotypic overlap with other hamartomatous polyposis syndromes. Germline mutations have been identified in MADH4 and BMPR1A, aiding in presymptomatic genetic testing. In this study, we describe the results from 3 years of molecular diagnostic screening in JPS. Seventy unrelated individuals referred to our lab for JPS testing were examined through the sequence analysis of coding regions and exon-intron boundaries in both genes. Germline mutations were identified in 30% of cases, with 11.4% in BMPR1A and 18.6% in MADH4. All mutation-positive individuals were negative for cancer at testing, and a single pulmonary valve stenosis was the only congenital anomaly reported. A majority of mutations identified were novel including the first splice site alteration in MADH4. Based on the limited number of exons in each gene, low polymorphism frequency, and high frequency of frameshift or nonsense mutations identified, direct sequence analysis is a suitable methodology for mutation screening if all coding regions and exon-intron boundaries are examined in both genes.

Adult↗
PubMed2005

Regulation of the cyclin-dependent kinase inhibitor p57Kip2 expression by p63.

The cyclin-dependent kinase (CDK) inhibitor p57Kip2 is a negative regulator of cell proliferation, binding to a variety of cyclin-CDK complexes and inhibiting their kinase activities. The p57Kip2 gene was recognized as a target gene for p73beta, one member of the p53 family. In spite of this, the phenotypes of p73 and p57Kip2 knockout mice do not resemble each other while there is a phenotypic overlap between the p57Kip2 null mice, the p63 null mice and patients affected by p63 associated syndromes, suggesting that p57Kip2 could be indeed a downstream target of p63. By ChIP we determined that in the HaCaT cell line the DeltaNp63alpha protein is associated to three different regions of the p57Kip2 gene. DeltaNp63 can activate both the endogenous p57Kip2 gene and a reporter vector containing a -2191 promoter fragment of the p57Kip2 gene. Natural p63 mutants, associated to the AEC syndrome, show a partial or complete lack of transactivation potential of the p57Kip2 promoter, while three other natural p63 mutants, associated to the EEC, LMS and SHFM-4 syndromes, were less affected. These data suggests that p63 play an important role in the regulation of p57Kip2 expression and that this regulation is subverted in AEC p63 mutants.

Animals↗
PubMed1999

New criteria for improved diagnosis of Bardet-Biedl syndrome: results of a population survey.

Bardet-Biedl syndrome (BBS) is an autosomal recessive condition characterised by rod-cone dystrophy, postaxial polydactyly, central obesity, mental retardation, hypogonadism, and renal dysfunction. BBS expression varies both within and between families and diagnosis is often difficult. We sought to define the condition more clearly by studying 109 BBS patients and their families, the largest population surveyed to date. The average age at diagnosis was 9 years, which is late for such a debilitating condition, but the slow development of the clinical features of BBS probably accounts for this. Postaxial polydactyly had been present in 69% of patients at birth, but obesity had only begun to develop at around 2-3 years, and retinal degeneration had not become apparent until a mean age of 8.5 years. Our study identified some novel clinical features, including neurological, speech, and language deficits, behavioural traits, facial dysmorphism, and dental anomalies. In the light of these features we propose a revision of the diagnostic criteria, which may facilitate earlier diagnosis of this disorder. We present evidence for an overlapping phenotype with the Laurence-Moon syndrome and propose a unifying, descriptive label be adopted (polydactyly-obesity-kidney-eye syndrome). We report an increased prevalence of renal malformations and renal cell carcinoma in the unaffected relatives of BBS patients and suggest that these may be a consequence of heterozygosity for BBS genes. Our findings have important implications for the care of BBS patients and their unaffected relatives.

Adolescent↗
PubMed2001

Exclusion of linkage to the CDL1 gene region on chromosome 3q26.3 in some familial cases of Cornelia de Lange syndrome.

Cornelia de Lange Syndrome (CdLS) is a complex developmental disorder consisting of characteristic facial features, limb abnormalities, hirsutism, ophthalmologic involvement, gastroesophageal dysfunction, hearing loss, as well as growth and neurodevelopmental retardation. Most cases of CdLS appear to be sporadic. Familial cases are rare and indicate autosomal dominant inheritance. Several individuals with CdLS have been reported with chromosomal abnormalities, suggesting candidate genomic regions within which the causative gene(s) may lie. A CdLS gene location (CDL1) has been assigned to 3q26.3 based on phenotypic overlap with the duplication 3q syndrome (critical region 3q26.2-q27) and the report of a CdLS individual with a balanced de novo t(3;17)(q26.3;q23.1). It has been postulated that a gene within the dup3q critical region results in the CdLS when deleted or mutated. We have performed a linkage analysis to the minimal critical region for the dup3q syndrome (that encompasses the translocation breakpoint) on chromosome 3q in 10 rare familial cases of CdLS. Nineteen markers spanning a region of approximately 40 Mb (37 cM) were used. Results of a multipoint linkage analysis demonstrated total lod-scores that were negative across the chromosome 3q26-q27 region. In 4/10 families, lod-scores were less than -2 in the 2 cM region encompassing the translocation, while in the remaining 6/10 families, lod-scores could not exclude linkage to this region. These studies indicate that in some multicase families, the disease gene does not map to the CDL1 region at 3q26.3.

Chromosomes, Human, Pair 3↗
PubMed2002

Early infantile form of spinal muscular atrophy (Werdnig-Hoffmann disease) with prolonged survival.

According to several previously used classification systems, spinal muscular atrophy (SMA) type I has been characterised by an early onset (< 6 months), severe course (patients are never able to sit without support) and fatal prognosis (death before 2-4 years). We report 36 out of 349 SMA type I patients (10%) who had an onset before 6 months and never learnt to sit but survived at least beyond their fifth birthday, in spite of total immobility and frequent respiratory infections. These data support a classification avoiding age at death as a criterion. In the subgroup of type I with prolonged survival, there was no difference in life span between those individuals who had an onset of disease at birth or before and those with symptoms starting after 3 months. Life span may be related to the ability to withstand repeated respiratory insult, as several of the sibships with children affected by similar neuromuscular compromise showed discordant ages at death. "Chronic" SMA I and SMA II may represent overlapping phenotypes as our index patients with SMA I had a sib with SMA.

Adolescent↗
PubMed2003

Breast cancer gene expression analysis--the case for dynamic profiling.

Cancer is a complicated disease with each individual tumor exhibiting to a variable degree a set of overlapping phenotypes that include abnormal proliferation and cell survival, genetic instability, tissue invasion, metastasis and angiogenesis. Each of these pathophysiological functions requires abnormal signaling that fails to respect the normal restraints imposed on healthy cells through homeostatic regulation. Understanding of deregulated gene expression is therefore an essential goal for cancer research because unraveling this problem will provide insights into the fundamental nature of cancer as well as provide opportunities for therapeutic intervention. Gene expression profiling is a remarkable technique that addresses this complexity by documenting the expression of thousands of genes at the level of mRNA abundance. From the standpoint of clinical investigation, the initial focus of gene profiling experiments has been on screening primary tumors for markers of poor prognosis. However this is only a first step in demonstrating the utility of this technique. Future advances will focus on understanding the evolution of an organ confined primary cancer to a treatment resistant lethal systemic disease through repeated tumor sampling and analysis, an approach termed in this paper "dynamic profiling". Using breast cancer endocrine therapy as an example our initial approaches to dynamic profiling will be described.

Aromatase Inhibitors↗
PubMed2004

Variable expressivity in a family with Kabuki make-up (Niikawa-Kuroki) syndrome.

Kabuki make-up syndrome (KS), also called Niikawa-Kuroki syndrome, is a rare congenital disorder of unknown etiology. Most KS cases occur sporadically and familial KS had never been reported in Taiwan. I describe four individuals in one family with KS. Significant intrafamilial variability in the clinical expression of this syndrome is evident. In addition to the typical craniofacial dysmorphism and cleft palate and/or cleft lip that the three children inherited from their father, rare anomalies such as lower lip pits and growth hormone deficiency in one girl and right-sided acrotia in one boy were noted. High-resolution banding did not detect any chromosomal structural anomalies. These findings further suggested the autosomal inheritance (from the father to two sons and one daughter) in KS and highlighted the overlapping phenotype with van der Woude syndrome.

Abnormalities, Multiple↗
PubMedDate not supplied

Bigenic connexin mutations in a patient with hidrotic ectodermal dysplasia.

Gap junctions are formed by a polygenic family of more than 20 different connexin proteins. They mediate intercellular communication via the direct exchange of ions, metabolites and secondary messengers, thus controlling and coordinating cellular activities. Mutations in five gap junction genes, including GJB2 (Cx26), GJB3 (Cx31), GJB4 (Cx30.3), GJB6 (Cx30) and GJA1 (Cx43) are known to cause inherited hearing loss and/or disorders of the skin and its appendages, often giving rise to overlapping phenotypes. In this study we present a patient with hidrotic ectodermal dysplasia, who had abortive features of oculo-dento-digital dysplasia, extensive hyperkeratosis of the skin. The patient harbored a novel sporadic mutation (V41L) in GJA1 (Cx43) as well as a heterozygous coding variant (R127H) of GJB2 (Cx26). Our findings suggest that GJA1 mutations can produce variable clinical phenotypes on the background of sequence variants in other connexins.

Child↗