deletions | additions       diff --git a/Etiology.md b/Etiology.md  index 6bc910b..09819d8 100644  --- a/Etiology.md  +++ b/Etiology.md 
...
A large collaborative group studied _AADAC_, the gene encoding arylacetamide deacetylase, in which microdeletions had been identified in a previous, smaller copy number variation study \citep{26444075}. The authors provide evidence from several sources supporting the connection of _AADAC_ and TS, including new patients with _AADAC_ deletions, a significant overall association, and evidence that _AADAC_ is expressed in the brain, though most strongly in cerebellum, hippocampus and olfactory bulb.  A collaborative genetic study \cite{26646788} \citep{26646788}  demonstrated an association of TS with 33 genes related to glycolysis or glutamine metabolism. None of the individual genes would have survived correction for multiple testing and the results were consistent with a combined effect of many genetic variants of small effect. These results narrow the hunt for genes that may contribute to the development of TS and they also suggest a new direction for future electrophysiological, imaging and pharmacological studies. A collaborative genetic study \citep{25735483} demonstrated an association of TS with 33 genes related to glycolysis or glutamine metabolism. None of the individual genes would have survived correction for multiple testing and the results were consistent with a combined effect of many genetic variants of small effect. These results narrow the hunt for genes that may contribute to the development of TS and they also suggest a new direction for future electrophysiological, imaging and pharmacological studies.