Additionally, constitutional chromothripsis is shown to affect the brain in a non-malignant disease. <...> Thus, constitutional chromosome instability in the brain is likely to be a mechanism for neuropathology in this devastating neuropsychiatric disease. <...> CYTOGENETICALLY VISIBLE COPY NUMBER VARIATIONS (CG-CNVS) IN BANDING AND MOLECULAR CYTOGENETICS OF HUMAN; ABOUT HETEROMORPHISMS AND EUCHROMATIC VARIANTS Liehr T. Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Jena, Germany Copy number variations (CNVs) having no (obvious) clinical effects were rediscovered as major part of human genome in 2004. <...> However, for every cytogeneticist microscopically visible harmless CNVs (CG-CNVs) are well known since decades. <...> Harmless CG-CNVs can be present as heterochromatic or even as euchromatic variants in clinically healthy persons. <...> Here I provide a review on what is known today on the still too little studied harmless human CG-CNVs, point out which can be mixed up with clinically relevant pathological CG-CNVs and shortly discuss that the artificial separation of euchromatic submicroscopic CNVs (MG-CNVs) and euchromatic CG-CNVs is no longer timely. <...> Overall, neither so-called harmless heterochromatic nor so-called harmless euchromatic CG-CNVs are considered enough in evaluation of routine cytogenetic analysis and reporting. <...> This holds especially true when bearing in mind the so-called twohit model suggesting that combination of per se harmless CNVs may lead to clinical aberrations if they are present together in one patient. <...> MYELODYSPLASTIC SYNDROME WITHOUT RING SIDEROBLASTS AND WITH JANUS KINASE 2 GENE MUTATION: AN UNUSUAL CASE REPORT Ornellas M. H.1,2 Gonзalves S. B. S.3 Silva J.4 1 , Seixas T. L.5 , de Franзa Silva M.1 , de Almeida L. S.1,2 , Bastos E. F.5,6 Rio de Janeiro, Brazil; 2 , Solza C.3 , de Lucena , de Paula Ayres , Liehr T.7 , Alves G.1,2,8 Department of Pathology, Laboratory of Circulating Markers, Faculty of Medica Sciences (FCM), Graduation Course in Medical Sciences, Faculty of Medica Sciences (FCM), Rio de Janeiro, Brazil; 3 (UERJ), Rio <...>