Project information

In cooperation with physicians in Syria and Germany, we, first, clinically examine numerous families with children which have intellectual disability, and include them in our study. Some families also visit our Institute for genetic counseling and can then join the study. The main focus of our group is the autosomal recessive forms of intellectual disability (e. g. two affected children of healthy parents).

In a second step, we conduct genome wide insertion-deletion analysis and follow on by genome wide mapping (linkage analysis or homozygosity mapping) to narrow down the locus of possible disease causing genes (e. g. Abou Jamra et al., EJHG 2011). In some cases, this step reveals the diagnosis by identifying a copy number change or by pointing out a known gene of ID in the candidate region.

In a third step, we conduct large scale sequencing using next generation sequencing technologies. We filter the identified variants based on established parameters. During this process there is a significant chance to identify a mutation in a previously described gene.

Finally, we aim at proving that the identified candidate mutations are truly the causing mutations. For that, several possible strategies exist: a) identifying a second mutation in the same gene in an independent family (e.g. Hansen et al., AJHG 2013); b) analyzing the gene function and interaction (e. g. based on literature) and the spectrum of symptoms of the affected patients and comparing this data with known syndromes and pathway diseases (e. g. Abou Jamra et al. , AJHG 2011); c) running functional analyses that prove the pathogenic effect of the mutation and the pathomechanism that leads to an impairment of neurological functions.

Identifying new genes of intellectual disability is the starting point for future actions. These first include providing the patients and their families with the novel available knowledge. Furthermore, understanding the pathomechanism is a fundamental step on the way to possible therapies.

All documents (consent forms and information material) for our project are available in German, English, and Arabic.

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