P-243: Prenatal Diagnosis Using Array CGH: Case Presentation

Background: Karyotype analysis has been the standard and reliable procedure for prenatal cytogenetic diagnosis since the 1970s. However, the major limitation remains requirement for cell culture, resulting in a delay of as much as 14 days to get the test results.CGH array technology has proven to be useful in detecting causative genomic imbalances or genetic mutations in as many as 15% of children with a normal conventional karyotype. We describe the use of array comparative genomic hybridization (aCGH) for prenatal diagnosis and the ability to detect abnormalities not detected by karyotype. Materials and Methods: A 26-year-old pregnant woman referred for prenatal diagnosis and genetic counseling at 27 weeks gestation because of an ultrasound detected fetal oligohydramnious and normal karyotype. She was offered array CGH analysis using a cytochip ISCA 4x44K oligonucelotide array. Parental samples were obtained concurrently to exclude maternal cell contamination and determine if copy number variations (CNVs) were de novo or inherited. Results: Whole-genome CGH array analysis on the DNA extracted from amniocytes detected a 17Mb deletion at 1q22-q25.1 or arr 1q22q25.1(154559773-171639287)x1. This deleted region encompassing at least 138 OMIM genes. After genetic counseling, the mother decided to continue the pregnancy. A female fetus was delivered at 37 weeks gestation by cesarean. She was diagnosed with bilateral cleft lip and palate, a transverse single palmar crease in right hand, a birth weight of 1800g, small hands and feet, hypotonia, short neck, normal head circumference, and a hemangioma on the back of the head. Conclusion: aCGH analysis of a fetus with normal karyotype and abnormal ultrasound finding is recommended.