1. Objectives: Describe the clinical features and chromosomal abnormality of r (20). Explain the examination and tests used to diagnose r ( 20). Summarize the medical and nursing interventions used to manage the symptoms of r (20). Chromosomal Abnormality A ring chromosome is an anomaly which is formed by the fusion of two arms of a straight chromosome during prenatal development. Individuals with r (20) syndrome have one copy of this abnormal chromosome in some or all of their cells. In some affected people, genes near the end of chromosome 20 are deleted when the ring chromosome forms and may be responsible for the epilepsy and other health issues. In other affected people, the ring chromosome may change the activity of certain genes on chromosome 20 or it may not be able to replicate itself normally during cell division. Clinical Features: Microcephaly Intellectual deficits Behavioral problems Slow growth and short stature Subtle differences in facial features, downslanting eyes, low placed ears, and small mouth and jaw Learning disabilities Abstract: R (20) syndrome is a disorder that affects normal development and function of the brain. The most common symptom of this disorder is recurrent seizures (epilepsy) beginning in early childhood. Often the seizures are complex and resistant to antiepileptic medications. Individuals with r (20) syndrome may have some cognitive and behavioral issues. What is r (20)? r (20) syndrome is ORPHA 1444 in the orphanet classification. The prevalence of the condition is not known, however more than sixty cases have been reported in the literature. Seizures present as complex partial seizures with progression to generalized tonic-clonic seizures. Epilepsy may present in infancy but is always seen by 3 years of age. The typical symptoms are frontal lobe seizures, ictal terrors, and hallucinations. Early in childhood, the EEG pattern shows rhythmic slow wave activity with spikes without clinical manifestations. The nonconvulsive status epilepticus episodes lead to cognitive impairment and deficits. r (20) is diagnosed using chromosomal analysis by looking at the karyotype in blood cells. Management of r (20) Syndrome: Anti-epileptics Broad spectrum anti-epileptic drugs are tried first (valproate, levetiracetam, lamotrigine, topiramate, and zonisamide Ketogenic diet High in fat and low in carbohydrate No published reports of its success in r (20) epilepsy Vagus Nerve Stimulation (VNS) therapy VNS has been tried with a reduction of seizures in some cases but not in others Long-term effectiveness of VNS therapy is not currently known Parent/family support and education WHAT IS r (20)? JEANIE K. BACHAND, Ed D, MSN, RN UNIVERSITY OF PHOENIX School of Advanced Studies Bibliography: Alpman, A., Serdaroglu, G., Ozgur, D., Tekgul, H., Gokben, S. & Ozkinay, F. (2007). Ring Chromosome 20 syndrome with intractable epilepsy. Developmental Medicine & Child Neurology, 46 (5), 343-346. Conlin, L.; Kramer, W.; Hutchinson, A.; Li, X.; Riethman, H.; Hakonarson, H.; Scheffer, I.; Berkovic, S.; Hosain, S. & Spinner, N. (2011). Molecular analysis of ring chromosome 20 syndrome reveals two distinct groups of patients. Journal of Medical Genetics, 48, 1-9.