I am a physician scientist, working as an associate professor in the Clinical Genetics Group (Karolinska Institutet) and as a specialist physician in the Clinical Genetics Department (Karolinska University Hospital). I received my Ph.D. degree in medical genetics from Karolinska Institutet (2010) and did postdoc research at the Center for Human Disease Modeling, Duke University, Durham, North Carolina led by Prof. Nicholas Katsanis (2010-2012).
Project 1: The role of structural genomic variation in human health and disease
Backgound: Structural genomic variation comprises 1) copy-neutral balanced events (inversions and translocations) as well as 2) unbalanced events with either loss or gain of chromosome material (deletions, duplications, triplications and multi allelic copy number variants (CNVs). The size may vary from events that are visible in a light microscope (>5-10 Mb) down to the size of a single exon (<100-200 base pairs). In the past decade structural variants have emerged as important contributors to the genetic load of both rare and common disorders especially within the area of neurodevelopmental disease and malformation syndromes. However, a specific rearrangement often affects many genes and regulatory regions and the specific disease causing factors are still poorly characterized.
Aim: These studies are focused on the detailed characterization of structural genomic rearrangements in order to identify the specific causative and modifying genes and to understand the underlying mutational mechanisms involved.
Work Plan: We use whole genome sequencing (WGS) to characterize and identify structural variants. Patents with structural variants are recruited through the clinical genetic diagnostic laboratory where individuals with neurodevelopmental disorders and malformation syndromes are analyzed with chromosome analysis and/or oligonucleotide array-based comparative genomic hybridization (aCGH). We have also developed a custom designed high-resolution aCGH platform. This array platform provides exon resolution in 2000 target genes important for ciliary function and embryo development. After WGS and bioinformatics analysis functional follow up studies of candidate genes and variants are done in primary patient cells (e.g. fibroblasts, lymphocytes), induced pluripotent stem cells and in zebrafish.
We have several ongoing studies:
Study I) Identification and characterization of rare disease associated structural chromosomal variants by massive parallel whole genome sequencing
The first objective is to implement WGS for the clinical diagnostic detection of structural variants. To this end, we develop novel bioinformatic analysis pipelines to identify both balanced and unbalanced structural variants from WGS data. The second objective is to study the rearrangement breakpoints and from the mutational signatures observed, infer the underlying mechanisms involved. Finally, we are interested in how the genes affected by structural variants cause disease. Our ambition is to characterize all genetic lesions in a given patient, from single base pair changes to large chromosomal rearrangements, and to follow up with functional studies. In this way, we will evaluate the relationship between structural variants and the burden of point mutations (an area that is still largely unexplored).
Study II) Identification of new disease genes by sequencing balanced chromosomal aberrations.
In this project we use WGS (described above) to study balanced chromosomal rearrangements (inversions and translocations). The hypothesis is that genes disrupted by the chromosomal breakpoints are driving the clinical symptoms seen in the rearrangement carriers. Identified candidate genes are evaluated in zebrafish.
III) Rare and common structural chromosomal variants in children with early onset obesity
This project, done in collaboration with Professor Outimaija Mäkitie, focus on the involvement of structural variation in children with early onset obesity. We know that genetic factors are important for the development of both mild and severe forms of obesity but the majority of the underlying genetics is still unknown. Especially in children with early-onset obesity we suspected a genetic defect. We have shown previously that the copy number variable region affecting the AMY1 gene is associated with early onset female obesity. We are now extending these studies into other genomic regions. Studies are done using targeted aCGH and WGS.
IV) Structural chromosomal variants in children with malformation syndromes
In this project, done in collaboration with Professor Agneta Nordenskjöld, we study point mutations and copy number variants in patients with congenital malformations by targeted aCGH and WGS.
V) Genetics of gonadal dysgenesis and primary ovarian insufficiency
In this project, done in collaboration with Ameli Norling and Professor Angelica Hirschberg, we study point mutations and copy number variants in patients with gonadal dysgenesis or primary ovarian insufficiency by targeted aCGH and WGS and relate this information to inheritance and disease causing probability.
Project 2: Zebrafish models and genetic mechanisms underlying rare human disorders
Despite recent progress in identifying the genetic cause of rare disorders we still lack the ability to interpret the pathogenic potential of rare variants identified in small families or in uncharacterized genes and assess the genetic basis of variability in clinical presentations. Due to the technical advantages, the zebrafish has become a very popular model to test and further understand the role of candidate genes in disease. Approximately 70% of the human genes have a zebrafish orthologue and many of the cellular pathways in embryonic development and tissue function are similar to those found in humans. One of the most commonly used techniques to assess the role of a specific gene is to knockdown the target protein levels using antisense oligonucleotides or morpholinos. This technique is however being replaced by the use of the genome editing technique CRISPR/Cas9. The CRISPR/Cas9 technique results in permanent changes in the genome that, given the specificity of the technique, more closely resemble the mutations found in the patients.
In this project we evaluate novel genes and mutations identified in patients with rare diseases investigated with clinical exome/whole genome sequencing or through our research studies outlined above. We use overexpression of wild type and mutated RNA, transient knock down (morpholinos) and stable knockdown (CRISPR/Cas9 mutagenesis). Disorders of particular interest are ciliopathies, gonadal dysgenesis, congenital malformation syndromes and muscle disorders.
Previous and Current Research Funding:
- 2017-2019 Stockholms läns landsting, ALF
- 2015-2018 Svenska Sällskapet för Medicinsk Forskning
- 2015-2017 Marianne och Marcus Wallenbergs Stiftelse
- 2015-2016 Science for Life Laboratory
- 2015-2017 Riksbankens Jubileumsfond
- 2015-2016 Jeanssons Foundation
- 2014-2016 Hjärnfonden
- 2015-2016 Kungl. Fysiografiska Sällskapet i Lund
- 2013-2015 Swedish Research Council (Vetenskapsrådet)
- 2016-2019 Karolinska Institutet
- 2013-2015 Stockholms läns landsting, ALF
- 2010-2013 Swedish Research Council (Vetenskapsrådet)
- Anna Lindstrand, MD, PhD, Team Leader
- Wolfgang Hofmeister, PhD, Assistant professor
- Ameli Norling, MD, PhD, Postdoc
- Josephine Wincent, MD, PhD, Postdoc
- Raquel Vaz, PhD, Postdoc
- Maria Pettersson, PhD student
- Jesper Eisfeldt, PhD student
- Miriam Armenio, Research Assistant
- Alisa Foerster, Master student
- Amel Al-Murrani, Research Assistant
Academic honors, awards and prizes
Academic honors, awards and prizes:
2016-2019 Selected for four year funding as Research Associate (forskarassistent), Karolinska Institutet
A novel intellectual disability syndrome caused by GPI anchor deficiency due to homozygous mutations in PIGT
Journal of medical genetics 2013;50(8):521-8
ARMC4 Mutations Cause Primary Ciliary Dyskinesia with Randomization of Left/Right Body Asymmetry
AMERICAN JOURNAL OF HUMAN GENETICS 2013;93(2):357-67
Inherited mosaicism for the supernumerary marker chromosome in cat eye syndrome: inter- and intra-individual variation and correlation to the phenotype
American journal of medical genetics. Part A 2012;158A(5):1111-7
Detailed molecular and clinical characterization of three patients with 21q deletions
CLINICAL GENETICS 2010;77(2):145-54
Further molecular and clinical delineation of co-locating 17p13.3 microdeletions and microduplications that show distinctive phenotypes
JOURNAL OF MEDICAL GENETICS 2010;47(5):299-311
Improved structural characterization of chromosomal breakpoints using high resolution custom array-CGH
CLINICAL GENETICS 2010;77(6):552-62
Molecular and Clinical Characterization of Patients With Overlapping 10p Deletions
AMERICAN JOURNAL OF MEDICAL GENETICS PART A 2010;152A(5):1233-43
Molecular Cytogenetic Characterization of a Constitutional, Highly Complex Intrachromosomal Rearrangement of Chromosome 1, With 14 Breakpoints and a 0.5 Mb Submicroscopic Deletion
AMERICAN JOURNAL OF MEDICAL GENETICS PART A 2008;146A(24):3217-22