MARFAN AND CRI DU CHAT SYNDROMES IN AN 18-MONTH-OLD CHILD - EVIDENCE OF PHENOTYPE INTERACTION

We report on an 18-month-old girl who has both the cri du chat and Mar fan syndromes. She was born at term to a 29-year-old woman with the cl inical diagnosis of Marfan syndrome. An evaluation for developmental d elay at 2 months of age showed a karyotype of 46,XX,del(5)(15.1), cons istent with cri du chat syndrome. At age 18 months she was tall (90 cm , > 95th centile), with an decreased upper segment:lower segment ratio (1.0), and microcephalic (OFC 42.5 cm, < 5th centile). Facial feature s were typical of cri du chat syndrome. The palm, middle finger and fo ot lengths were at or above the 95th centile for age. She was hypotoni c, and her developmental level was approximately 8-10 months. Echocard iography showed redundant mitral valve tissue, mild mitral insufficien cy, dilated aortic sinuses, and a small muscular VSD. We would have an ticipated that a patient with an autosomal deletion who also had Marfa n syndrome would have had growth failure. However, in this patient the skeletal features of Marfan syndrome (increased body length, decrease d upper segment:lower segment ratio, and increased palm, finger, and f oot length) predominate.