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2014

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Articles 1171 - 1200 of 1243

Full-Text Articles in Medical Sciences

The Role Of The Developing Microbiome In Mucosal Defense Of The Neonatal Gut, Emily G. Blosser Jan 2014

The Role Of The Developing Microbiome In Mucosal Defense Of The Neonatal Gut, Emily G. Blosser

All ETDs from UAB

Neonatal late-onset sepsis is invasive infection occurring after the first 48 hours of life, and one of the leading causes of death among preterm infants in the United States and abroad. Infections with Gram-negative bacteria, such as Klebsiella pneumonia, occurring when bacteria translocate across premature gut epithelium into the bloodstream, can be particularly severe. Preterm infants in the neonatal intensive care unit undergo intense antibiotic regimens due to high risk of infection. Paradoxically, prolonged exposure of preterm infants to empiric antibiotic therapy early in the hospital stay is associated with increased risk of intestinal infection and death after adjustment for …

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The Involvement Of The Ca2+-Independent Phospholipase A2ss In The Pathogenesis Of Type 1 Diabetes, Robert N. Bone Jan 2014

The Involvement Of The Ca2+-Independent Phospholipase A2ss In The Pathogenesis Of Type 1 Diabetes, Robert N. Bone

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chapters test the role of non-steady moisture or temperature on sex ratios produced by the

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Engineering Fibroblast-Remodeled Electrospun Matrices For Full-Thickness Skin Regeneration, Paul Bonvallet Jan 2014

Engineering Fibroblast-Remodeled Electrospun Matrices For Full-Thickness Skin Regeneration, Paul Bonvallet

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Skin is often severely damaged, resulting in the need for surgical intervention. There are many limitations to current therapies, therefore a synthetic skin graft would be invaluable for skin regeneration. The focus of the current study is on developing engineered scaffolds with embedded dermal fibroblasts that can be remodeled into native skin tissue upon implantation. To achieve this goal we created electrospun scaffolds composed of collagen I and polycaprolactone (PCL), and then introduced pores to allow fibroblast infiltration. In initial experiments performed to optimize pore size and collagen to PCL concentration, we determined that a 160 µm pore diameter, and …

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Development Of A Patient-Derived Xenograft Model Of Ovarian Cancer To Characterize The Chemotherapy Resistant Population, Zachary Christopher Dobbin Jan 2014

Development Of A Patient-Derived Xenograft Model Of Ovarian Cancer To Characterize The Chemotherapy Resistant Population, Zachary Christopher Dobbin

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Ovarian cancer while the second most common gynecologic malignancy is the most commons cause of death due to a gynecologic malignancy and the fifth most common cause of death to cancer in women. In 2014, there will be an expected 21,980 cases and 14,270 deaths. Unfortunately, the five-year survival for ovarian cancer is only 40% and this has barely increased over the past 30 years. New approaches need to be developed in order to study ovarian cancer and identify methods of overcoming chemotherapy resistance. This dissertation presents the work conducted in the development of a patient-derived xenograft model of ovarian …

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Evidence Of Altered Ampa Receptor Localization And Regulation In Schizophrenia, Jana Drummond Jan 2014

Evidence Of Altered Ampa Receptor Localization And Regulation In Schizophrenia, Jana Drummond

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Although the glutamate hypothesis of schizophrenia posits altered glutamatergic transmission is occurring in this illness, the precise mechanisms be-hind these proposed changes in schizophrenia brain remain elusive. Recent evidence from our laboratory supports a model of altered forward trafficking of glutamate receptors to synaptic membranes in schizophrenia, which could contribute to changes in neurotransmission. The AMPA subtype of ionotropic glutamate receptor (AMPAR), is the main facilitator of fast, excitatory neurotransmission in the brain, and changes in AMPAR number at synapses may control synaptic strength and plasticity. One mechanism that could alter AMPAR trafficking to synapses is abnormal expression of AMPAR …

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The Role Of The Planar Cell Polarity Pathway In The Second Heart Field During Outflow Tract Morphogenesis, Tanvi Sinha Jan 2014

The Role Of The Planar Cell Polarity Pathway In The Second Heart Field During Outflow Tract Morphogenesis, Tanvi Sinha

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Outflow Tract (OFT) malformations underlie a majority of congenital heart defects (CHD) in humans and are a leading cause of childhood mortality. The OFT, which gives rise to the aorta and pulmonary artery of the heart, relies on the contribution of the Second Heart Field (SHF) progenitors in the pharyngeal and the splanchnic mesoderm, outside of the initial heart. OFT morphogenesis requires highly regulated SHF development involving the proliferation, differentiation and deployment of the SHF progenitors to the heart. Extensive studies elegantly demonstrate how transcriptional networks integrating signaling input from multiple pathways finely balance the proliferation and differentiation of SHF …

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Effects Of Storage On The Red Blood Cell And Its Implications For Transfusion, Ryan D. Stapley Jan 2014

Effects Of Storage On The Red Blood Cell And Its Implications For Transfusion, Ryan D. Stapley

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Transfusion with red blood cells (RBC) remains a frontline therapy in critically ill patients. Recent studies have documented an association between storage duration and an increased incidence of transfusion-related toxicities. This transfusion-related toxicity is characterized by both a pro-inflammatory state and a microcirculatory dysfunction and is associated with changes that occur to the RBC and its media during storage referred to as the storage lesion. These changes that occur to the RBC include an increase in cell-free hemoglobin, heme, free iron, microparticles, as well as changes to the RBC itself. This thesis explores how these elements could contribute to transfusion-related …

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Modulation Of The Immune Response To Aspergillus Fumigatus By Antibodies To Conserved Bacterial Polysaccharides, Emily Stefanov Jan 2014

Modulation Of The Immune Response To Aspergillus Fumigatus By Antibodies To Conserved Bacterial Polysaccharides, Emily Stefanov

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The incidence of asthma, allergies and autoimmune diseases has increased dramatically in developed countries. The hygiene hypothesis postulates that excessively sanitary conditions lead to a lack of critical immune stimulation during early life, leading to inappropriate responses to self or harmless antigens later in life. Many bacteria and potential allergens share common polysaccharide epitopes. We investigated the ability of antibodies against these shared polysaccharides to dampen the immune response to the ubiquitous fungus and potent allergen, Aspergillus fumigatus. We found that antibodies against these polysaccharides, specifically of the IgM isotype, induced by neonatal bacterial immunization or passive antibody transfer, dampened …

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Translocation Of Shed Syndecan-1 To The Nucleus: A Novel Mechanism Of Tumor-Host Crosstalk, Mark Stewart Jan 2014

Translocation Of Shed Syndecan-1 To The Nucleus: A Novel Mechanism Of Tumor-Host Crosstalk, Mark Stewart

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Multiple myeloma is a hematological malignancy of plasma cells that disseminates throughout the body. Crosstalk between myeloma and host cells is critical to the establishment of a microenvironment conducive to tumor growth and progression. An important mediator of this crosstalk is syndecan-1, a heparan sulfate proteoglycan. Syndecan-1 is proteolytically shed from the surface of myeloma cells and is abundant in the bone marrow microenvironment and serum of myeloma patients. Shed syndecan-1 facilitates tumor-host crosstalk within the microenvironment to drive tumor growth, angiogenesis, and metastasis. We now report for the first time that shed syndecan-1 can be taken up by a …

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Characterization Of Phosphatidylinositol 4,5-Bisphosphate Regulation Of The Electrogenic Na/Bicarbonate Cotransporter Nbce1, Ian Michael Thornell Jan 2014

Characterization Of Phosphatidylinositol 4,5-Bisphosphate Regulation Of The Electrogenic Na/Bicarbonate Cotransporter Nbce1, Ian Michael Thornell

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The electrogenic Na/bicarbonate cotransporter (NBCe1) is an acid/base regulator that is also involved in coordinating epithelial ion transport. Splice variants of NBCe1 differ at their cytosolic amino- (N-) and/or carboxy- (C-) termini. These different cytosolic termini impart differential regulation for each variant. For example, the N-terminus of NBCe1-A is autostimulatory, whereas the N-terminus of NBCe1-B and -C is autoinhibitory. We examine the regulatory role of PIP2 for NBCe1 splice variants. In the first study of this dissertation, we characterize the effect of increasing PIP2 on the activity of NBCe1-A, -B, and -C expressed in Xenopus laevis oocytes. Injecting PIP2 stimulated …

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Targeting Tau-Mediated Nmdar Hypofunction Reverses Deficits In A Mouse Model Of Frontotemporal Dementia, Brian Andrew Warmus Jan 2014

Targeting Tau-Mediated Nmdar Hypofunction Reverses Deficits In A Mouse Model Of Frontotemporal Dementia, Brian Andrew Warmus

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Frontotemporal dementia (FTD) is a rapidly progressive and lethal disease, with no disease-modifying treatments. It is known that tau mutations cause FTD, but the underlying neurobiology is undefined. We sought to identify how tau affects the neurobiology in order to find potential treatment targets. Here, we address this question using a new mouse model expressing human tau with an FTD-associated mutation. We studied behavior, physiology, biochemistry, and neuropathology in several cohorts of mice at different ages. These mutant tau mice had abnormal repetitive behavior characteristic of FTD and synaptic deficits selectively in regions associated with FTD (ventral striatum and insula). …

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Peripheral Neuropathy In The Teetering Mice Results From Mutation Of The Escrt Component Hrs, Jennifer Ashley Watson Jan 2014

Peripheral Neuropathy In The Teetering Mice Results From Mutation Of The Escrt Component Hrs, Jennifer Ashley Watson

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The sorting and degradation of endocytosed cargo by the endosome regulates many cellular functions common to all cells. Neural cells appear to be particularly vulnerable to perturbation in endo-lysosomal transport, and several neurological disorders are caused by a primary deficit in this pathway. In this dissertation, I show that the spontaneously occurring neurological mutation teetering (tn) is a single nucleotide substitution in the endosomal cargo-sorting component hepatocyte growth factor-regulated tyrosine kinase substrate (Hgs/Hrs) that reduces the abundance of HRS. By 3 weeks of age, the tn mice exhibit heightened pain sensitivity, muscle weakness and reduced muscle size. The loss of …

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Using Neuroimaging To Predict Treatment Response In Patients With Schizophrenia, Nathan Lyle Hutcheson Jan 2014

Using Neuroimaging To Predict Treatment Response In Patients With Schizophrenia, Nathan Lyle Hutcheson

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Schizophrenia is a severe debilitating mental illness that affects approximately 1% of people worldwide. Compared to healthy controls (HC), patients with schizophrenia (SZ) have memory deficits, specifically prominent disruptions in their episodic memory. These memory disruptions are thought to be caused by altered structure and function of areas within the memory network, specifically the prefrontal and temporal lobe including the hippocampus. Recently, identifying biomarkers of treatment response by using neuroimaging has become a prominent area of interest in schizophrenia. Biomarkers in schizophrenia could help by allowing for more efficient treatment using current method and also the development of novel treatments. …

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Mechanisms Of At101 [(-)-Gossypol] Induced Cytotoxicity In Malignant Peripheral Nerve Sheath Tumors, Niroop Kaza Jan 2014

Mechanisms Of At101 [(-)-Gossypol] Induced Cytotoxicity In Malignant Peripheral Nerve Sheath Tumors, Niroop Kaza

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Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive Schwann cell-derived sarcomas and are the leading cause of mortality in patients with neurofibromatosis type 1 (NF1). Current treatment modalities have been largely ineffective resulting in a high rate of MPNST recurrence and poor five year patient survival. This necessitates the exploration of alternative chemotherapeutic options for MPNST patients. By evading apoptosis and utilizing protective mechanisms such as autophagy, cancer cells develop resistance to chemo- and radio-therapy. The overall goal of my thesis studies is to evaluate chemotherapeutic agents that can modulate both apoptosis and autophagy, thus target both cell death pathways …

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The Role Of Il-7 And C-Kit Signaling Pathways In Specification Of B Lymphocytes, Oleg Kolupaev Jan 2014

The Role Of Il-7 And C-Kit Signaling Pathways In Specification Of B Lymphocytes, Oleg Kolupaev

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B-lymphocyte commitment from common lymphoid progenitors (CLP) is orchestrated by a number of transcription factors and extracellular developmental cues. Most prominently, IL-7 signaling acts as a critical factor for promotion of B cell differentiation through its role in upregulation of the B-cell commitment factor, Ebf1, by activation of Jak-Stat5 signaling. Other cytokines and growth factors secreted by bone marrow stromal cells, such as Flt3 ligand, are known to modulate developmental outcomes by regulating the IL-7R-Jak-Stat5 pathway. The role of stem cell factor (SCF), the ligand of the receptor tyrosine kinase (RTK) c-Kit, and the mechanism by which it affects cell …

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Evaluation Of Tau As A Target For Alzheimer Disease And Other Conditions With Epileptiform Activity, Zhiyong Li Jan 2014

Evaluation Of Tau As A Target For Alzheimer Disease And Other Conditions With Epileptiform Activity, Zhiyong Li

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Alzheimer disease (AD) is a devastating neurological condition that slowly destroys memory and thinking skills of the affected patients. No disease-modifying medications are available. While all the treatment against Aߒ (major component of one hallmark pathology of AD) failed in clinical trials, tau (major component of the other hallmark pathology of AD) is emerging as a better alternative. Germline knockout of tau does not cause overt abnormalities in young mice and prevents AD-like deficits in mouse models of AD. Germline knockout of tau also confers resistance to epileptiform activity in models of both AD and epilepsy. Therefore tau is proposed …

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Type I Interferons-Induced Follicular Translocation Of Lymphotoxin-Expressing Marginal Zone B Cells Initiates Lupus, Hao Li Jan 2014

Type I Interferons-Induced Follicular Translocation Of Lymphotoxin-Expressing Marginal Zone B Cells Initiates Lupus, Hao Li

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Systemic lupus erythematosus (SLE) is characterized by elevation of type I interferon (IFN) signature genes and production of autoantibodies against apoptotic self-antigens. The complex nature of SLE, however, suggests that multiple immune dysregulations must integrate to initiate the disease. Here, we provided evidence that lupus can be initiated via type I IFNs-induced follicular translocation of membrane lymphotoxin (mLT)-expressing marginal zone (MZ) B cells in the spleen of lupus prone BXD2 mice. The mislocation of mLT+ MZ B cells induces two important pathogenic effects including deteriorations of marginal zone macrophages (MZMs) in the MZ, leading to defective clearance of apoptotic debris, …

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Ksrp Ablation Enhances Lipolysis In White Adipose Tissue Through Reduced Mir-145 Expression, Yi-Yu Lin Jan 2014

Ksrp Ablation Enhances Lipolysis In White Adipose Tissue Through Reduced Mir-145 Expression, Yi-Yu Lin

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White adipose tissue (WAT) releases fatty acids from stored triacylglycerol (TAG) for energy source. Here, we report that null mice for KH-type splicing regulatory protein (KSRP), an RNA-binding protein, resisted high fat diet (HFD) induced obesity. Target of deletion of KSRP regulates gene expression at multiple levels and enhances lipolysis in epididymal WAT (eWAT) due to up-regulation of genes promoting lipolytic activity. Expression of miR-145 is decreased due to impaired pri-miR-145 processing in Ksrp-/- eWAT. We show that miR-145 directly targets and represses Foxo1 and Cgi58, activators of lipolytic activity, and forced expression of miR-145 attenuates lipolysis. This study reveals …

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Expression Of The Influenza Protein M2 During Viral Infection Inhibits Cftr Activity, James David Londino Jan 2014

Expression Of The Influenza Protein M2 During Viral Infection Inhibits Cftr Activity, James David Londino

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The purpose of these dissertation studies was to 1) determine whether influenza infection alters CFTR activity in polarized epithelium; 2) measure CFTR expression and activity in cells co-expressing influenza M2 protein; and 3) examine the role of M2 on the alteration of CFTR during viral infection. We determined that infection of polarized primary epithelial cells with influenza decreases CFTR expression and activity. In addition, individual cells infected with influenza had decreased CFTR conductance as measured by whole-cell patch clamp. We also found that the influenza ion channel, matrix protein 2 (M2), alone reduced CFTR expression and activity. M2 is expressed …

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Transmitted/Founder Siv In The Rhesus Macaque Model Of Hiv-1 Infection, Mike Lopker Jan 2014

Transmitted/Founder Siv In The Rhesus Macaque Model Of Hiv-1 Infection, Mike Lopker

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Vitally important to HIV-1 vaccine and prevention studies is a well-characterized animal model that recapitulates the salient features of HIV infection in humans. SIVmac and SIVsmm infection of rhesus macaques share key virological and pathological parallels with HIV-1 infection of humans including target cell entry via CD4 and CCR5 (Edinger et al., 1997), progressive T cell loss (Swanstrom & Coffin, 2012), generalized immune activation and preferential loss of mucosal Th17 cells (Brenchley et al., 2008; Klatt & Brenchley, 2010), and a vigorous but ultimately ineffective adaptive immune response. Though commonly used as a vaccine challenge strain in the macaque model, …

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The Role Of The Autophagy-Lysosome Pathway In In Vitro Models Of Neurodegeneration, Burton Mader Jan 2014

The Role Of The Autophagy-Lysosome Pathway In In Vitro Models Of Neurodegeneration, Burton Mader

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Recent studies have provided strong evidence that alterations in protein degradation pathways, such as the autophagy-lysosome pathway (ALP), may contribute to neuronal dysfunction and death which lead to clinical symptoms diagnosed with various neurodegenerative diseases. Parkinson's disease (PD) is characterized by neuromuscular abnormalities resulting from the pathological loss of substantia nigra dopaminergic neurons and widespread detection of Lewy bodies, intracellular protein inclusions composed primarily of α-synuclein. Additionally, altered gene function regulating the expression of α-synuclein has been directly linked to the PD pathogenesis. Autophagy is an intracellular degradation process that when altered can lead to the accumulation neurotoxic proteins such …

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Glial Fibrillary Acidic Protein And Gliosis: Is Gfap More Than A Marker?, Heather Renee Minkel Jan 2014

Glial Fibrillary Acidic Protein And Gliosis: Is Gfap More Than A Marker?, Heather Renee Minkel

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Alexander Disease (AxD) is a `gliopathy' caused by toxic, dominant gain-of-function mutations in the gene encoding glial fibrillary acidic protein (GFAP). Two distinct types of AxD exist. Type I AxD affected individuals develop cerebral symptoms by four years of age and generally suffer from macrocephaly, seizures, and physical and mental delays. As detection and diagnosis have improved, a larger portion, now about half of all AxD patients diagnosed, have onset >4 years and brainstem/spinal cord involvement. These type II AxD patients typically experience ataxia, palatal myoclonus, dysphagia and dysphonia. To date no study has examined a mechanistic link between the …

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The Role Of Primary Cilia In Mammary Gland And Skeletal Development, Elizabeth Mitchell Jan 2014

The Role Of Primary Cilia In Mammary Gland And Skeletal Development, Elizabeth Mitchell

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and satiation of predators. Additionally, the arribada significantly affected sex ratios and

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Structural Implications Of P22 Bacteriophage Coat Protein A-Domain Modifications, David Samuel Morris Jan 2014

Structural Implications Of P22 Bacteriophage Coat Protein A-Domain Modifications, David Samuel Morris

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Modification of virus capsids as target-specific delivery devices has become highly popularized in recent years and P22 bacteriophage has been proposed as a potential candidate for development of a targeting drug delivery system. As a proof of concept for our system, we hypothesized that the A-domain of P22 coat protein could be utilized to alter the binding affinity of virus-like procapsids for biological targets. Addition of acidic residues to the A-domain revealed that this could be accomplished through the quarternary localization of charged residues in three-dimensional space without interrogating procapsid assembly. Further manipulations implemented in vivo were performed to examine …

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Altered Dna Methylation Contributes To Temporal Lobe Epilepsy And Associated Memory Deficits, Robert Ryley Parrish Jan 2014

Altered Dna Methylation Contributes To Temporal Lobe Epilepsy And Associated Memory Deficits, Robert Ryley Parrish

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Status epilepticus (SE) triggers molecular mechanisms that underlie the cellular and network changes that occur during the development of temporal lobe epilepsy (TLE). Additionally, gene expression alterations occur during epileptogenesis and in the epileptic brain that contribute to the persistence of the phenotype. However, the underlying epigenetic mechanisms responsible for aberrant gene expression that occur with epilepsy require further investigation. This dissertation investigates how DNA methylation in the hippocampus affects epilepsy and contributes to the memory impairments associated with the disorder. We found that DNA methylation was altered in a hippocampal subregion specific manner in the epileptic brain, displaying altered …

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The Impact Of Interleukin-21 On Intestinal Inflammation During Health And Disease, Catherine Poholek Jan 2014

The Impact Of Interleukin-21 On Intestinal Inflammation During Health And Disease, Catherine Poholek

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The intestinal environment is extremely complex due to the dynamic interactions between host cells and luminal contents. The immune cells located in the intestine are responsible for sensing and responding to intestinal pathogens as well as maintaining tolerance to non-pathogenic organisms and environmental antigens. Disruption in this delicate balance results in chronic intestinal inflammation. Particularly important to the maintenance of intestinal homeostasis are CD4 T cells and innate lymphoid cells (ILCs). These cells produce cytokines in an antigen-specific and antigen-independent manner, respectively, and have analogous subsets with similar cytokine profiles. CD4 T cells and ILCs expressing ROR gamma t (Th17 …

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Molecular And Functional Interaction Of Runx2 And Sp7 For Development Of The Osteoblast Phenotype, Harunur Rashid Jan 2014

Molecular And Functional Interaction Of Runx2 And Sp7 For Development Of The Osteoblast Phenotype, Harunur Rashid

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Runx2 and Sp7 transcription factors are essential for skeletogenesis. Deletion of either gene in mice results in failure of bone tissue development. However, underlying mechanisms responsible for a surprisingly similar phenotype by two distinctly unrelated proteins remain unknown. Sp7 is a Runx2 downstream target gene and is not expressed in Runx2 null mice. Thus, the Runx2 null model represents a compound phenotype of loss of both proteins. In contrast, normal levels of Runx2 mRNA are noted in Sp7 null mice. The failure of Runx2 to promote bone formation in Sp7 null mice suggests that Sp7 is required for Runx2 function …

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Epithelial Sodium Channel Purification And X-Ray Crystallographic Studies, Bharat G. Reddy Jan 2014

Epithelial Sodium Channel Purification And X-Ray Crystallographic Studies, Bharat G. Reddy

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Epithelial sodium channels (ENaC) play a critical role in maintaining Na+ homeostasis in various tissues throughout our body. Understanding of ENaC structure is mediated from studies of the homologous acid sensing ion channel 1 (ASIC1). However, ENaC has sev-eral notable functional differences compared to ASIC1, thereby providing justification for determination of its three-dimensional structure. Unfortunately, this goal remains elu-sive due to several experimental challenges. Of the subunits that comprise a physiological hetero-trimeric ENaC (α, ß, and γ), the α-subunit alone is of significant interest. αENaC is unique in that it is capable of forming a homo-trimeric structure capable of conducting …

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Modulation Of Neocortical Gabaergic Interneurons By Voltage-Gated Ion Channels, Sidney B. Williams Jan 2014

Modulation Of Neocortical Gabaergic Interneurons By Voltage-Gated Ion Channels, Sidney B. Williams

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GABAergic interneurons provide the main source of inhibition in the neocortex and are important in regulating neocortical network activity. In the presence of the K+ channel blocker 4-AP and the glutamate receptor blockers, CNQX and D-APV, large amplitude evoked and spontaneous depolarizing responses are observed in the neocortex. These large propagating responses are blocked by GABAA receptor antagonists indicating that these events are due to synchronized activity of GABAergic interneurons. Cortical GABAergic networks are comprised of several types of interneurons, each with its own protein expression pattern, receptor profile, firing properties, synaptic targets and role in network activity. Voltage-gated ion …

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Identification Of A New Schwannomatosis-Predisposing Gene And Study Of Splicing Defects Caused By Deep Intronic Nf1 Mutations Causing Neurofibromatosis Type 1, Jing Xie Jan 2014

Identification Of A New Schwannomatosis-Predisposing Gene And Study Of Splicing Defects Caused By Deep Intronic Nf1 Mutations Causing Neurofibromatosis Type 1, Jing Xie

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Schwannomatosis is the third major form of the neurofibromatoses. Constitutional mutations in the SMARCB1 gene have been found only in ~50% of familial and <10% of sporadic schwannomatosis patients, suggesting additional predisposing genes exist. In the present study, we sequenced 3.72 Mb of evolutionary conserved sequences along 22q in 8 schwannomatosis patients without a SMARCB1 mutation in blood or schwannomas, and had a molecular signature consisting of somatic partial loss of 22q and a different NF2 mutation in every schwannoma. We identified LZTR1 germline mutations in 7/8 patients. Targeted sequencing of LZTR1 in 12 further patients with the same molecular signature identified 9 additional germline mutations. Loss of heterozygosity with retention of the LZTR1 mutation was present in all 25 schwannomas studied. Mutations segregated with disease in all available affected first-degree relatives. Our findings identify LZTR1 as a gene predisposing to an autosomal dominant inherited disorder of multiple schwannomas in ~80% SMARCB1-negative 22q-related schwannomatosis patients. Neurofibromatosis type 1, another major form of neurofibromatoses, is caused by loss-of-function mutations in the NF1 gene. Approximately 2% of identified NF1 mutations are deep intronic splice mutations causing the inclusion of an intronic cryptic exon in the mature mRNA. In the present study, we identified 12 different deep intronic splice mutations in 15 unrelated probands, resulting in exonization of different fragments from intron 30(23.2) or 31(23a). This study describes the largest collection of deep intronic mutations in NF1 reported so far, and pinpoints specifically the intronic sequences flanking the alternatively spliced exon 31(23a) as a hotspot for NF1 intronic splice defects. Further investigation by fragment and cloning analysis uncovered that the deep intronic mutations residing either 5' or 3' of exon 31(23a) predominantly or preferentially affect the type II isoform including exon 31(23a), suggesting that alternative splicing of exon 31(23a) depends and is regulated by multiple flanking intronic sequences.

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