Abstracts

Rationale: Microarray analysis (MA) is a technique that identifies genetic imbalance, such as supernumerary markers, and areas of loss of heterozygosity. Its diagnostic role in pediatrics is still evolving, mainly focused on finding etiology of developmental delays. The objective of this study is to describe our experience at our institution, including neurologic symptoms, to determine MA usefulness to Pediatric Neurologists. Methods: We retrospectively reviewed the charts of patients who had MA performed and normal karyotype. Collected clinical data included age, gender, presence of MR, developmental delay, autism, learning disability, hypotonia, dysmorphic features and/or epilepsy. Statistical analysis was performed using SPSS. Results: A total of 80 patients were included, mean age 5.6±5 years, 43(54%) males and 37(46%) females. MA was abnormal in 16(20%). Three additional children had increased homozygosity suggesting uniparental disomy: total abnormal results=19(24%). Deletions comprised 74% of all abnormalities, the most common in chromosome 7(n=4). Patients with 4 or more positive clinical variables had a 30% incidence of abnormal MA, compared with 8.7% in patients with 3 or less (p=0.037, Chi-square). A logistic regression analysis of the clinical variables showed that motor delay (p=0.04) and presence of epilepsy (p=0.046) independently contributed to the model. Conclusions: MA analysis had a diagnostic yield of 24% in our sample, and was related to an increased number of clinical abnormalities. False positive results and need for parental testing could limit the use of this technique. However, it is likely that MA will become the genetic test of choice in children with MR, ND, and/or epilepsy.