Paul Gissen - Academia.edu (original) (raw)

Papers by Paul Gissen

$Research paper thumbnail of A novel VPS33B mutation in an ARC syndrome patient presenting with osteopenia and fractures at birth$

American Journal of Medical Genetics Part A, 2007

Journal of Medical Genetics, 2007

Paediatrics and Child Health, 2011

Glycogen storage disorders are a group of inborn errors of metabolism characterized by accumulati... more Glycogen storage disorders are a group of inborn errors of metabolism characterized by accumulation of glycogen in various tissues. This accumulation is the histological hallmark of these disorders although the phenotype shows variable overlap. Hepatomegaly, hypoglycaemia, elevated lactate and urate with or without neutrophil dysfunction are the classical presentations for the commonest disorders namely GSD types I a, 1b and III. Elevated creatine kinase, weakness, hypertrophic cardiomyopathy with or without rhabdomyolysis represent the commonest muscle subtypes with the best known ones being GSD II, III and V. Control of glucose deficiency by added calories, tube feeding or modified cornstarch is frequently the main basis of treatment. Supportive therapies are needed to establish near normality. Potential curative therapies are enzyme replacement therapies by mode of liver transplantation, bone marrow transplantation or use of recombinant enzyme. Keywords bone marrow transplantation; cornstarch; enzyme replacement therapy; GSD or glycogen storage disease; hypertrophic cardiomyopathy; inborn error of glycogen metabolism; liver transplantation; rhabdomyolysis SYMPOSIUM: INBORN ERRORS OF METABOLISM PAEDIATRICS AND CHILD HEALTH 21:2 84

Journal of thrombosis and haemostasis : JTH, 2015

Inherited platelet function disorders (PFDs) are heterogeneous, and identification of the underly... more Inherited platelet function disorders (PFDs) are heterogeneous, and identification of the underlying genetic defects is difficult when based solely on phenotypic and clinical features of the patient. To analyze 329 genes regulating platelet function, number, and size in order to identify candidate gene defects in patients with PFDs. Targeted analysis of candidate PFD genes was undertaken after next-generation sequencing of exomic DNA from 18 unrelated index cases with PFDs who were recruited into the UK Genotyping and Phenotyping of Platelets (GAPP) study and diagnosed with platelet abnormalities affecting either Gi signaling (n = 12) or secretion (n = 6). The potential pathogenicity of candidate gene defects was assessed using computational predictive algorithms. Analysis of the 329 candidate PFD genes identified 63 candidate defects, affecting 40 genes, among index cases with Gi signaling abnormalities, while 53 defects, within 49 genes, were identified among patients with secreti...

Journal of neurology, 2014

Niemann Pick disease type C (NP-C) is a rare autosomal recessive disorder that results from mutat... more Niemann Pick disease type C (NP-C) is a rare autosomal recessive disorder that results from mutations in either the NPC1 or the NPC2 gene. The estimated incidence of NP-C is 1 in 120,000 live births, although the frequency of cases is higher in some isolated populations. More than 350 different NPC1 and NPC2 gene mutations have been reported in patients with confirmed diagnoses. Approximately 95 % of patients harbour mutations in NPC1, with most of the remaining patients having NPC2 mutations. The traditional methods for diagnosing patients with NP-C include histopathological analysis of bone marrow aspirate, liver and skin biopsies, fluorescent and electron microscopy, and cholesterol esterification assays. New laboratory methods that use mass spectroscopy for detection of cholesterol metabolism products are promising to become part of the routine diagnostic and screening tests in the near future, but further evaluation is required to determine the sensitivity and specificity of th...

Hämostaseologie, 2010

Platelet number or function disorders cause a range of bleeding symptoms from mild to severe. Pat... more Platelet number or function disorders cause a range of bleeding symptoms from mild to severe. Patients with platelet dysfunction but normal platelet number are the most prevalent and typically have mild bleeding symptoms. The study of this group of patients is particularly difficult because of the lack of a gold-standard test of platelet function and the variable penetrance of the bleeding phenotype among affected individuals. The purpose of this short review is to discuss the way in which this group of patients can be investigated through platelet phenotyping in combination with targeted gene sequencing. This approach has been used recently to identify patients with mutations in key platelet activation receptors, namely those for ADP, collagen and thromboxane A2 (TxA2). One interesting finding from this work is that for some patients, mild bleeding is associated with heterozygous mutations in platelet proteins that are co-inherited with other genetic disorders of haemostasis such a...

Human molecular genetics, Jan 15, 2005

VPS33B protein is a homologue of the yeast class C vacuolar protein sorting protein Vps33p that i... more VPS33B protein is a homologue of the yeast class C vacuolar protein sorting protein Vps33p that is involved in the biogenesis and function of vacuoles. Vps33p homologues contain a Sec1 domain and belong to the family of Sec1/Munc18 (SM) proteins that regulate fusion of membrane-bound organelles and interact with other vps proteins and also SNARE proteins that execute membrane fusion in all cells. We demonstrated recently that mutations in VPS33B cause ARC syndrome (MIM 208085), a lethal multisystem disease. In contrast, mutations in other Vps33p homologues result in different phenotypes, e.g. a mutation in Drosophila melanogaster car gene causes the carnation eye colour mutant and inactivation of mouse Vps33a causes buff hypopigmentation phenotype. In mammals two Vps33p homologues (e.g. VPS33A and VPS33B in humans) have been identified. As comparative genome analysis can provide novel insights into gene evolution and function, we performed nucleotide and protein sequence comparisons...

Arthrogryposis-renal dysfunctioncholestasis (ARC) syndrome is a rare autosomal recessive multisys... more Arthrogryposis-renal dysfunctioncholestasis (ARC) syndrome is a rare autosomal recessive multisystem disorder caused by mutations in vacuolar protein sorting 33 homologue B (VPS33B) and VPS33B interacting protein, apical-basolateral polarity regulator (VIPAR). Cardinal features of ARC include congenital joint contractures, renal tubular dysfunction, cholestasis, severe failure to thrive, ichthyosis, and a defect in platelet alpha-granule biogenesis. Most patients with ARC do not survive past the first year of life. We report two patients presenting with a mild ARC phenotype, now 5.5 and 3.5 years old. Both patients were compound heterozygotes with the novel VPS33B donor splice-site mutation c.1225+5G>C in common. Immunoblotting and complementary DNA analysis suggest expression of a shorter VPS33B transcript, and cell-based assays show that c.1225+5G>C VPS33B

Clinics in liver disease, 2013

Neonatal conjugated jaundice is a common presentation of hereditary liver diseases, which, althou... more Neonatal conjugated jaundice is a common presentation of hereditary liver diseases, which, although rare, are important to recognize early. Developments in molecular genetic techniques have enabled the identification of causative genes, which has improved diagnostic accuracy for patients and has led to a greater understanding of the molecular pathways involved in liver biology and pathogenesis of liver diseases. This review provides an update of the current understanding of clinical and molecular features of the inherited liver diseases that cause neonatal conjugated jaundice.

Clinical Kidney Journal, 2013

Arthrogryposis, renal dysfunction and cholestasis (ARC) syndrome is a multisystem autosomal-reces... more Arthrogryposis, renal dysfunction and cholestasis (ARC) syndrome is a multisystem autosomal-recessive disorder caused by defects in the VPS33B and VIPAR genes, involved in localization of apical membrane proteins. Affected children usually die by 1 year of age, often secondary to infective complications. The classic renal manifestation previously described in ARC syndrome is proximal-tubular dysfunction. The aim of this study is to gain further insight into the renal manifestations of this syndrome. Clinical review of three cases of ARC syndrome presenting to a tertiary centre. Together with measurement of VPS33B and VIPAR protein expression in the human glomerulus. The cases demonstrated severe failure to thrive and in addition to commonly described features profound proteinuria and albuminuria, together with hypoalbuminaemia, suggesting glomerular involvement of this syndrome. Western blotting of conditionally immortalized human glomerular cells and ex vivo immunofluorescent analysis of the human glomerulus revealed that VPS33B and VIPAR were highly expressed in glomerular endothelium, and podocytes, but not in the mesangium. ARC syndrome affects the glomerulus as well as the proximal tubule in the kidney. Our molecular studies suggest that both cell types that constitute the glomerular filtration barrier are affected in this condition, providing an explanation for the albuminuria that we have observed in our cases.

Inherited methylmalonic acidurias are a group of autosomal recessive disorders caused by mutation... more Inherited methylmalonic acidurias are a group of autosomal recessive disorders caused by mutations in the genes encoding methylmalonyl CoA mutase and proteins involved in cobalamin (Vitamin B12) metabolism. Methylmalonic aciduria can also arise as a result of severe cobalamin deficiency. We report the case of a male infant presenting at 5 months of age with a cobalamin sensitive methylmalonic aciduria, pancytopaenia, developmental delay, failure to thrive, hepatosplenomegaly and hypotonia. MRI brain imaging showed reduced white matter quantity and maturity. The cause was investigated and discovered to be a maternal subclinical pernicious anaemia. A rapid clinical improvement was made upon initiation of B12 supplementation. At follow up aged 18 months weight was above the 91st centile and height between the 75th and 90th. Although no delay in fine motor or social skills was noted at 18 month assessment, gross motor and language delay persisted and may reflect central nervous system damage due to the initial B12 deficiency.