TY - CHAP M1 - Book, Section TI - Tetrasomy 12p (Pallister–Killian Syndrome) A1 - Bianchi, Diana W. A1 - Crombleholme, Timothy M. A1 - D'Alton, Mary E. A1 - Malone, Fergal D. Y1 - 2015 N1 - T2 - Fetology: Diagnosis and Management of the Fetal Patient, 2e AB - Key PointsCharacterized by tissue-specific presence of an abnormal extra chromosome, which consists of two copies of the short arm of chromosome 12.Abnormal (marker) chromosome is more likely to be found in amniocytes or fibroblasts than blood.Associated with advanced maternal age.Sonographic findings: polyhydramnios, diaphragmatic hernia, rhizomelic short limbs.Main consideration in differential diagnosis is Fryns syndrome.Very poor long-term prognosis. All survivors are mentally retarded.Sporadic inheritance. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - obgyn.mhmedical.com/content.aspx?aid=1106402255 ER -