Trisomy 18-Like Syndrome

Clinical Features

Shashi et al. (1996) described a newborn infant with first-cousin parents who had a complex congenital heart defect and minor anomalies suggestive of trisomy 18. Blood lymphocyte and skin fibroblast karyotypes were normal. He died in the neonatal period from postoperative complications. On interphase fluorescence in situ hybridization (FISH) using autopsy specimens, a significant number of cells in the liver (17%) were trisomic for chromosome 18, compared to normal controlled liver tissue. However, interphase FISH analyses of blood lymphocytes, skin fibroblasts, and kidney tissue were normal. Shashi et al. (1996) concluded that the apparent mosaicism for trisomy 18 in the liver may have been spurious, and that the pattern of anomalies, together with the parental consanguinity, may indicate a new autosomal recessive malformation syndrome. The illustrated appearance of the patient was unusual with broad nasal root, narrow palpebral fissures, telecanthus, deficient alae nasi, apparently low-set ears which were malformed, preauricular tags, and micrognathia.