A mosaic small supernumerary marker chromosome 17 in a patient with Tourette syndrome, ADHD and intellectual disability: A case story and review of the literature

Characterization of a de novo sSMC 17 detected in a girl with developmental delay and dysmorphic features

“…In Table 1 we present overlapping cases from the literature. The presence of sSMC 17 encompassing only the pericentric regions appears to be associated predominantly with developmental delay and in some cases with intellectual disability, meanwhile patients with sSMC 17 of larger parts of either the short or the long arm of chromosome 17 have additional dysmorphic features [11]. The duplicated genomic region of the present case is the most comparable to that of Chen et al [15], although our proband’s heart examination did not reveal any abnormalities.…”

“…It results in an inappropriate development and working of the whole central nervous system, which could be a reason for the proband’s developmental delay. It has been shown that TRAF4 is attractive gene for movement disorders [11], so we can suggest that duplication of TRAF4 is probably involved in our patient’s hyperactivity. This observation remains speculative and needs to be confirmed in other similar cases or functional studies.…”

“…Second gene TRAF4 (OMIM 602464) encodes TNF receptor-associated factor 4, which is required during embryogenesis for the formation of the trachea, the axial skeleton and the closure of neural tube. In addition, TRAF4 plays a role in proper myelination therefore its role in ADHD, intellectual disability and movement disorder has been previously suggested [11]. Other genes within the duplicated region were also of interest for possible genotype-phenotype correlations.…”

“…Both cases manifested with developmental delay and speech delay, despite the fact that sSMC 17 in the Chen et al case was in a mosaic form. Cornelius et al described another similar case [11] and suggested that the duplication of NOS2 plays a role in the ADHD symptoms of their patient. Cornelius et al also suggested that the duplication of TRAF4 plays a role in ADHD, intellectual disability and movement disorder.…”