Abstracts

Rationale: 18p deletion syndrome (18pDS) is the deletion of all or a portion of genetic material on the short arm of chromosome 18. Most cases are de novo deletions. 18pDS is associated with developmental delay, short stature and facial dysmorphism. Prior studies have shown that the incidence of seizures in patients with 18pDS is infrequent; but has been described in patients with 18qDS with a frequency ranging from 10-31 %. This case report describes the third child identified with 18p deletion syndrome and seizures.Methods: Chromososmal analysis was performed by The Division of Medical Genetics at Schneider Children's Hospital.Results: The patient was born via c-section, twin B, no complications. Developmental delays were noted early on and she received early intervention services: physical, speech and occupational therapies. Genetic testing revealed 46, XX, del(18)(p11.2). Patient later diagnosed with coarctation of the aorta, mild autism spectrum disorder and strabismus requiring surgery. At 15 years of age she presented to the emergency room with three episodes of staring, unresponsiveness, lip smacking and drooling each lasting 20-40 seconds. On examination she had frontal bossing, epicanthal folds, and narrow nasal bridge, neurological examination was otherwise normal. She had an EEG that showed frequent, brief runs of lateralized rhythmic delta activity with embedded sharp waves (LRDA +S) over the left temporal region and, isolated, sharp waves over the right temporal region. Cerebellar white matter changes were noted on brain MRI. The patient was started on oxcarbazepine with good effect.Conclusions: 18pDS is a rare genetic abnormality leading to developmental delays and facial dysmorphisms. Only 2 cases of 18pDS have been described in the literature with epilepsy. First, a young male who developed nocturnal seizures with occasional secondary generalization with EEG showing spike and sharps waves over the frontal-central regions and occurring synchronously or less often asynchronously was described. Chromosome analysis revealed 46 XY, del(18)(p11.1pter). A second case was described in a child with West syndrome. This is the third case of 18pDS with epilepsy described. Additional reports will be necessary to determine the association between chromosome 18p and seizures.