BJÖRNSSON LAB: WHAT HAVE WE LEARNED?

Since 2012:

A method to predict loss of function intolerance (2020). We have shown that CpG content can be used to predict loss of function intolerance in very small genes.

The first mouse model of Kabuki syndrome (2014). We characterized the first mouse model of Kabuki syndrome (Kmt2d^+/βGeo mice) and demonstrated that these mice have many features seen in patients (growth retardation, skeletal problems, learning problems). This model also revealed novel features such as an ongoing defect of adult neurogenesis (see Bjornsson et al. Science TM, 2014). 

Proof-of-principle studies that demonstrate that Kabuki syndrome may be a treatable cause of intellectual disability (2014, 2017). We have shown that hippocampal memory defects and defects of adult neurogenesis improve upon treatment with agent that favor chromatin opening and thereby counter the defect (TAK-418, AR-42, ketogenic diet, BHB injection, see Bjornsson et al. Science TM, 2014; Benjamin J, 2017, PNAS, Zhang et al. Molecular Therapy, Methods and Clinical Development, 2021).

Novel insights into the basis of Kabuki syndrome (2019). We have observed precocious differentiation in neurons and mesenchymal cells in mouse models of Kabuki syndrome (See Fahrner and Carosso in JCI Insight, 2019). 

DNA methylation as a biomarker in Kabuki syndrome (2017). We recently showed that DNA methylation patterns are abnormal in Kabuki syndrome. These changes may have use as a diagnostic biomarker (see Sobreira et al. EJHG, 2017).

The description of the novel Bjornsson-Pilarowski syndrome (2018). We recently found mutations in the chromatin remodeler CHD1 in patients with autism and speech apraxia (see Pilarowski et al. JMG, 2017).

Insights into haploinsufficiency of the Mendelian disorders of the epigenetic Machinery (2015, 2018). In a recent review article we pointed out that even though epigenetic writers and erasers and remodelers are enzymes, these predominantly cause disease when one copy is lost (haploinsufficiency) which is exceedingly rare for enzymes. We extended this observation to the entire subset of the epigenetic machinery components (almost 300) and find that haploinsufficiency is mainly seen in a subset of epigenetic machinery components that show extensive co-expression in the GTEX dataset. It is possible that this co-expression phenotype plays a role in the haploinsufficiency of these factors (see Bjornsson et al. Genome Research, 2015; Boukas et al. Genome Research, 2019).  

Prior to 2012:

Insights into germline DNA methylation through studies of a mutational biomarker (Bjornsson et al. Gene, 2004; Sigurdsson M et al. Gene, 2012; Sigurdsson M et al. Genome Research, 2009;  Sigurdsson M et al. BMC genetics, 2012).

Demonstration of that DNA methylation changes over time in humans (Bjornsson et al. JAMA, 2008).

Demonstration that allele-specific expression abnormalities are common in humans (Bjornsson et al. Genome Research, 2008).

Demonstration that loss of imprinting in Wilms Tumors is specific (Bjornsson et al. JNCI 2007).