Pallister-Killian Syndrome Presenting With a Complex Congenital Heart Defect and Increased Nuchal Translucency

allister-Killian syndrome (PKS, also referred as tetrasomy 12p) is a rare sporadic chromosomic anomaly characterized by the presence, most often in a mosaic arrangement, of isochromosome 12p.1–3 Patients have 4 copies of the short arm of chromosome 12 instead of the normal 2. Prenatal diagnosis is made by showing the presence of the supernumerary isochromosome by fluorescence in situ hybridization in amniotic fluid, a chorionic villus sample, or fetal lymphocytes.3,4 Such a chromosomic defect is most often associated with multiple morphologic anomalies, such as a diaphragmatic hernia, rhizomelic shortening of the limbs, cardiac and urogenital defects, joint contractures, and facial dysmorphic features.1,4 However, these anomalies may not be fully expressed during the first half of pregnancy, which makes early prenatal diagnosis by sonography difficult. Neurodevelopmental delays, seizures, and abnormal skin pigmentation are common in postnatal survivors with PKS.5 To date, about 60 cases of prenatally diagnosed PKS have been published.4 Either the diagnosis has been made after the sonographic detection of fetal anomalies,2 or it has been an unexpected finding after fetal karyotyping for maternal age.4 Recently, an association of PKS with increased nuchal translucency (NT) in the first trimester of pregnancy has been reported.1 The effectiveness of this sonographic marker for detection of both chromosomic defects and anatomic anomalies is now well established, and its use as a screening tool in the first trimester of gestation has become widespread.6,7 Likewise, in recent years, the ability of early echocardiography to detect fetal congenital heart disease early in high-risk pregnancies has been proved.8 Here, we report a case of early prenatal diagnosis of PKS made by showing both increased NT and a complex congenital cardiac defect in the setting of a screening program for common aneuploidies in the first trimester. Received April 10, 2006, from the Ultrasound and Fetal Physiopathology Unit, Department of Obstetrics and Gynecology (D.E.A., J.A.G., A.G.I.), and Human Genetics Unit (A.M.I.), Hospital Universitario 12 de Octubre, Madrid, Spain; and Department of Human Anatomy and Embryology, Faculty of Medicine, University of Extremadura, Badajoz, Spain (C.L.-S., V.G.-M.). Revision requested May 1, 2006. Revised manuscript accepted for publication May 25, 2006. This work was supported in part by grant 3PR05A058 from the Plan Regional de Investigacion, Consejeria de Educacion, Ciencia y Tecnologia, Junta de Extremadura. Address correspondence to Alberto Galindo Izquierdo, MD, Servicio de Obstetricia y Ginecologia, Hospital Universitario 12 de Octubre, Avenida de Cordoba s/n, 28041 Madrid, Spain. E-mail: agalindo.hdoc@salud.madrid.org Abbreviations NT, nuchal translucency; PKS, Pallister-Killian syndrome