Human Ring Chromosomes - chapter 18

The exact physiopathology of ring chromosome 14 syndrome (RC14) (OMIM#616606) is currently unknown but it defnitely does not rely only on the 14q deleted region, as the clinical severity does not correlate with the deletion size and gene content. The resulting clinical picture belongs to the large group of neurodevelopmental disorders associated with epilepsy, which represents the most penetrant and relevant clinical feature. The typical phenotype is further characterized by distinct facial features, psychomotor delay/ intellectual disability, and ocular anomalies. Some carriers of RC14 also exhibit heterogeneous and complex different rearrangements, involving deletions and partial duplications of 14q. RC instability may also be observed, as cytogenetic testing has revealed cells with a loss, double- or multiple-ring confgurations of the RC14, in addition to the prevalent disomic and single-ring harboring cell line. These observations may also contribute to the remarkable clinical variability. Banding cytogenetics is the primary means of detecting RC14, often suggested by the presence of a 14q terminal deletion detected through chromosome microarray analysis (CMA). Current management is mainly supportive: we here review and report available evidences on standard therapies and follow-up, discussing the importance of a multidisciplinary approach since the diagnosis, for patients and their families.