Professor Paul Gissen

Gissen Lab

The Gissen Lab uses cell and molecular biology approaches to investigate rare genetic disorders affecting intracellular trafficking and metabolism, and use this knowledge to develop novel therapies to treat these disorders.

The team is located at the UCL Great Ormond Street Institute of Child Health but is also fully integrated into the Great Ormond Street Hospital (GOSH) Clinical Research Facility for our clinical trials work. We receive competitive funding from academic sponsors such as the MRC, LifeArc, NIHR, Action Medical Research, Rosetrees and GOSH Charity. We collaborate with the industry sponsors on development of therapies for Rare Paediatric Disorders.

Team Members

Claudiu Cozmescu

Postdoctoral Researcher, Gissen Lab

Claudiu's journey in gene therapy began during his undergraduate studies at University College London (UCL), where he developed a keen interest in this innovative field. He pursued his passion further by completing a Master's in Cell and Gene Therapy, followed by a PhD focused on developing in vivo lentiviral gene therapies for ARC syndrome. Currently, Claudiu is a postdoctoral researcher in the Genetics and Genomic Medicine Research and Teaching Department at UCL's Institute of Child Health. His work, funded by an Action Medical Research grant, is dedicated to addressing Progressive Familial Intrahepatic Cholestasis type 3 in a similar way as he did ARC syndrome. In addition to his research, Claudiu serves as Co-Director for the Molecular Aspects of Cell and Gene Therapy module at the GOS UCL Institute of Child Health. This role allows him to engage with a variety of cutting-edge gene therapy technologies, enhancing his expertise beyond lentiviral vectors.

Outside the lab, Claudiu enjoys indoor climbing, travelling and exploring culinary delights through food and wine tasting.

Ziyu Jiang

PhD Student, Gissen Lab

Ziyu obtained her Bachelor's degree in Biochemical Engineering from UCL and she is currently doing her PhD at UCL Great Ormond Street Institute of Child Health. She has always been interested in developing novel therapies for rare diseases. Her PhD research is funded by the NIHR BRC and focuses on developing lentiviral vector-based gene therapy for progressive-familial intrahepatic cholestasis type 2 (PFIC2).

In her free time, Ziyu likes to do a bit of baking and cooking. 

Christos Lazaridis

Clinical Research Fellow in Paediatric Metabolic Medicine, NIHR GOSH, Gissen Lab

Christos is a Clinical Research Fellow at Great Ormond Street Hospital (GOSH), dedicated to advancing research in paediatric metabolic disorders. His journey in Medicine began in Greece, where he completed his official training in Paediatrics. With seven years of experience in the field, he has cultivated a keen interest in the challenges and innovations within Inborn Errors of Metabolism. Christos holds two Master’s degrees—one in Basic Research Methodology and another in Nanoscience and Nanotechnology, both in metabolic-related studies—reflecting his commitment to integrating clinical practice with research innovation.

In his downtime, Christos enjoys photography, theatre, and exploring art-related fields, as well as travelling and immersing himself in diverse cultures.

Mina Nazari

Research Assistant, Gissen Lab

Mina's academic journey began at King's College London, where she completed her undergraduate studies in Biomedical Science. Her professional career took off at the Francis Crick Institute, where she was part of the Genetic Modification Service team. She then returned to King's College London to work at the Randall Centre of Cell & Molecular Biophysics, focusing on identifying and characterizing cis-regulatory modules that control endodermal gene expression in zebrafish. In early 2022, Mina joined Gissen's Lab in the Genetics and Genomic Medicine Department at the Great Ormond Street Institute of Child Health. Funded by the Great Ormond Street Hospital Charity, her current research focuses on the blood and immune aspects of Arthrogryposis, Renal dysfunction, and Cholestasis (ARC) syndrome. Mina's current work is centred on developing an ex-vivo lentiviral gene therapy for ARC syndrome in mouse models of this disease.

In her free time, Mina enjoys activities such as running, hiking and working out, as well as spending time in nature.

Berna Seker Yilmaz

Research Fellow, Gissen Lab

Berna obtained her medical degree from the University of Ankara. Following her Paediatrics training, she specialised in inherited metabolic disorders and now serves as a locum consultant at Evelina London Children’s Hospital.

She was awarded an Associate Professor of Paediatric Metabolic Medicine by Turkish Council of Higher Education and is actively involved in UG and PG medical education, supervision and mentoring in Turkey and UCL. She teaches across the UCL campus and is a module lead on the MSc Paediatrics and Child Health AP Programme.

Berna’s research focuses on gene therapy development programs for inborn errors of metabolism. She currently leads the natural history study for Ornithine Transcarbamylase Deficiency and her current project work aims to better understand infantile forms of Niemann Pick Disease Type C (NPC) in collaboration with International Niemann Pick Disease Registry (INPDR) and several UK metabolic centres.

In her spare time, Berna enjoys travelling, writing and spending time with her family.

Siyamini Sivananthan

NIHR GOSH BRC Clinical Training (PhD) Fellow, Zhou, Heywood & Gissen Lab

Siyamini is currently an NIHR-GOSH Biomedical Research Centre PhD Training Fellow, and is working on the development of novel RNA therapies for neurodegenerative lysosomal storage disorders. In particular, she aims to utilise recent advances in antisense oligonucleotide therapy to achieve this goal. This work is supported by collaborations with the Zhou Lab and the Translational Mass Spectrometry research group. Previously, Siyamini worked as a Clinical Research Fellow at the NIHR Clinical research facility at GOSH, working on a number of high-intensity gene therapy trials. She is also a Royal College of Paediatrics and Child Health subspecialty ('GRID') trainee in Paediatric Inherited Metabolic Diseases. Her initial medical training was at the University of Cambridge, where she also received an intercalated undergraduate degree in Natural Sciences.

In her spare time, Siyamini enjoys baking and gardening with her two young children. 

Tomasz Tomkiewicz

Research Fellow, Zhou & Gissen Lab

Tom is a postdoctoral researcher who completed his PhD at Radboud University Medical Centre in Nijmegen, Netherlands. His doctoral research focused on developing antisense oligonucleotide therapy for Stargardt disease, an inherited retinal disorder. Tomasz has since joined the research groups of Prof. Paul Gissen and Prof. Haiyan Zhou, where he is dedicated to advancing mRNA therapy for hereditary tyrosinemia - a metabolic disorder affecting tyrosine metabolism.

In his free time, Tomasz enjoys running, boxing, and reading about ancient history.

Katy Vecchiato

Clinical Research Fellow, Gissen Lab

Katy obtained her medical degree from the University of Trieste (Italy), and specialised in General Paediatrics. She then completed a PhD at King's College London, where she investigated the use of advanced brain magnetic resonance imaging (MRI) in childhood epilepsies to improve treatment outcomes. Currently, Katy works as a Clinical Research Fellow at the NIHR Clinical Research Facility in GOSH, focusing on paediatric metabolic clinical trials.

In her leisure time, Katy enjoys playing tennis and attending jazz concerts.

Patricia Cheng

Visiting Associate, Gissen Lab

Patricia’s UG and MSc background is in computational linguistics, and she is technically trained in ServiceNow with an in-depth understanding of a number of programming languages. She is a visiting associate in the Gissen group and supports Prof. Paul Gissen.

In her spare time, Patricia enjoys pilates, painting and reading.

Key Collaborators

UCL: Julien Baruteau, Claire Booth, Steve Hart, Wendy Heywood, Manju Kurian, David Long, Kevin Mills, Philippa Mills, Ahad Rahim, Adrian Thrasher, Simon Waddington, Haiyan Zhou.

External collaborators: Ye Oo and Girish Gupte (University of Birmingham and Birmingham Women’s and Children’s Hospital), Leszek Lisowski and Ian Alexander (University of Sydney), Tim Yu (Boston Children’s Hospital), Denny Porter and Win Arias (National Institutes of Health).

External organisations: Bloomsbury Genetic Therapies, EveryOne Medicines, Neurogene, BioMarin, Orchard Therapeutics.

Selected Publications

• Eichler F, Duncan C, Musolino PL, et al. Lentiviral Gene Therapy for Cerebral Adrenoleukodystrophy. N Engl J Med. 2024 (In Press).
• Gaur P, Gissen P, Biswas A, et al. Enzyme replacement therapy for CLN2 disease: MRI volumetry shows significantly slower volume loss compared to a natural history cohort. Am J Neuroradiol. ajnr.A8408. 2024
• Spaull R, Soo AK, Batzios S, et al. Evolution of Movement Disorders in Patients With CLN2-Batten Disease Treated With Enzyme Replacement Therapy. Neurology. 103:e209615. 2024
• Specchio N, Gissen P, de Los Reyes E et al. Exploring concurrent validity of the CLN2 Clinical Rating Scale: Comparison to PedsQL using cerliponase alfa clinical trial data. PLoS One. 19:e0302382. 2024
• Bremova-Ertl T, Ramaswami U, Brands M et al. Trial of N-Acetyl-l-Leucine in Niemann-Pick Disease Type C. N Engl J Med. 390:421-431. 2024
• Gurung S, Timmermand OV, Perocheau D et al. mRNA therapy corrects defective glutathione metabolism and restores ureagenesis in argininosuccinic aciduria. Science Translational Medicine. 16:eadh1334. 2024
• Schulz A, Specchio N, de Los Reyes E et al. Safety and efficacy of cerliponase alfa in children with neuronal ceroid lipofuscinosis type 2 (CLN2 disease): an open-label extension study. Lancet Neurol. 2024 Jan;23(1):60-70.
• Baruteau J, Cunningham SC, Yilmaz BS, et al. Safety and efficacy of an engineered hepatotropic AAV gene therapy for ornithine transcarbamylase deficiency in cynomolgus monkeys. Mol Ther Methods Clin Dev. 23:135-146. 2021
• Lorvellec M, Pellegata AF, Maestri A, et al. An In Vitro Whole-Organ Liver Engineering for Testing of Genetic Therapies. iScience. 23:101808. 2020
• Scietti L, Chiapparino A, De Giorgi F, et al. Molecular architecture of the multifunctional collagen lysyl hydroxylase and glycosyltransferase LH3. Nat Commun. 9:3163. 2018
• Schulz A, Ajayi T, Specchio N, et al. Study of Intraventricular Cerliponase Alfa for CLN2 Disease. N Engl J Med. 378:1898-1907. 2018
• Eichler F, Duncan C, Musolino PL, et al. Hematopoietic Stem-Cell Gene Therapy for Cerebral Adrenoleukodystrophy. N Engl J Med. 377:1630-1638. 2017
• Hanley J, Dhar DK, Mazzacuva F, et al. Vps33b is crucial for structural and functional hepatocyte polarity. J Hepatol. 66:1001-1011. 2017
• Banushi B, Forneris F, Straatman-Iwanowska A, et al. Regulation of post-Golgi LH3 trafficking is essential for collagen homeostasis. Nat Commun. 7:12111. 2016
• Bem D, Smith H, Banushi B, et al. VPS33B regulates protein sorting into and maturation of α-granule progenitor organelles in mouse megakaryocytes. Blood. 126:133-43. 2015
• Cullinane AR, Straatman-Iwanowska A, Zaucker A, et al. Mutations in VIPAR cause an arthrogryposis, renal dysfunction and cholestasis syndrome phenotype with defects in epithelial polarization. Nat Genet. 42:303-12. 2010
• Gissen P, Johnson CA, Morgan NV, et al. Mutations in VPS33B, encoding a regulator of SNARE-dependent membrane fusion, cause arthrogryposis-renal dysfunction-cholestasis (ARC) syndrome. Nat Genet. 36:400-4. 2004