Denna sida på svenska
Loading profile information...

About me

I am a physician scientist, working as an associate professor in the Clinical Genetics Group (Karolinska Institutet, KI) 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). Since June 2017 I am a group leader for the rare diseases research group at KI.

Research description

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:

 

Team members:

 

Alumni:

  • Miriam Armenio, Research Assistant
  • Alisa Foerster, Master student
  • Amel Al-Murrani, Research Assistant

Academic honours, awards and prizes

Academic honors, awards and prizes:

2015 Recipient of of the Jeanssons Foundation personal award to particularly outstanding young researchers

2015-2017 Recipient of a three-year fellowship from Riksbankens Jubileumsfond

2015-2018 Awarded four years of funding from Svenska Sällskapet för Medicinsk Forskning (SSMF:s stora anslag)

2015-2017 Awarded 3 years of funding for clinical scientists from Marianne och Marcus Wallenbergs Stiftelse

2016-2019 Selected for four year funding as Research Associate (forskarassistent), Karolinska Institutet

Loading publication list...

Map