P09.02: Tetrasomy 9p with septated cystic hygroma, nonossified nasal bone, prominent midface, Dandy Walker malformation, cardiac and limb anomalies

Abstract

A 38-year-old, G6 P 4013 was referred at 16 weeks following the finding of a septated cystic hygroma with nuchal translucency 5.6 mm at 11 weeks. Mutiple abnormalities were present, including septated cystic hygroma, non-ossified nasal bone, micrognathia, Dandy-Walker malformation (DWM), hydrocephalus, pericardial effusion, suspected inlet VSD and pulmonic stenosis, and limb abnormalities including hyperextended left knee and right clubfoot. After genetic counseling, amniocentesis was performed; all colonies showed 47 chromosomes with an isodicentric chromosome 9 with the breakpoint on the long arm at band q21, with tetrasomy for the short arm of chromosome 9 and the region between the centromere and the band q21 on the long arm. Tetrasomy 9p is a very rare, with about 50 cases reported. Manifestations include mental retardation, growth restriction, CNS abnormalities including DWM and agenesis of the corpus callosum, hypertelorism, micrognathia, cleft lip/palate, and cardiac, limb, and renal abnormalities. Only a handful of cases have been diagnosed prenatally; findings have included strawberry shaped head, DWM, cleft lip, cardiac anomalies, hyperechoic kidneys, arthrogryposis and, and clubfeet. This is the first reported case with prenatal sonography showing a cystic hygroma. Supporting information can be found in the online version of this abstract. Counterclockwise: Cystic hygroma, profile showing nonossifed nasal bone and micrognathia, hyperextended knee, clubfoot. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.