The group is active since 2005 and its research was originally focused mainly on mitochondrial diseases. Our aims were to identify and characterize human genes involved in the biogenesis of the mitochondrial respiratory chain (RC), identify mutations in patients with RC defects, and to develop simple tools to characterize these mutants and to study the pathophysiology of these disorders and test novel therapeutic approaches. In the past years we have expanded our research focus to include also other metabolic diseases, as well as genetic disorders unrelated to cellular metabolism. Regarding the latter, we have developed a novel diagnostic strategy for genetic disorders based on NGS technology. Using a 2-level approach we now have the capability to provide a molecular diagnosis for over 90% of known genetic diseases in a clinical setting.
Based on our previous work we have developed three main lines of research, wich we are currently pursuing.
The first line of research deals with the biogenesis of the RC, in particular of Coenzyme Q biosynthesis and its regulation. Using CRISPR-CAS9 we have generated several KO cell lines for genes which are (or are presumed to be) involved in these processes. These cells were instrumental to determine the correct sequence of reactions in the CoQ biosynthetic pathway in humans.
The second one involves metabolic disorders, in particular vitamin B6-dependent enzymes such as ornithine aminotransferase (OAT). We are currently studying the molecular pathogenesis of OAT deficiency and therapeutic role of vitamin B6 and its vitamers in patients.
The last field of research deals with genetic diseases in general. The expansion of our diagnostic service has provided us with an incredible amount of genetic data (we have analyzed >3000 patients with NGS, for a variety of different conditions). The main limitation of this approach is that it is often very difficult to establish the pathogenicity of identified variants, especially of synonymous and missense exonic changes and of intronic variants outside the canonical splicing consensus. The reliability of prediction software is still problematic in a diagnostic setting; hence there is a clear necessity for experimental tools to validate these mutations. In the past years, we have developed several models from hybrid minigenes, to yeast, CRISPR-CAS9 edited human cells, and C. elegans that have allowed us to validate (or to dismiss ass neutral polymorphisms) many novel variants, and to establish genotype-phenotype correlations for different diseases. We have employed these strategies to identify three new genes associated with human diseases: MCM5, ADCK2, and TOGARAM.