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 Marfan syndromes. She was born at term to a 29-year-old woman with the clinical diagnosis of Marfan syndrome. An evaluation for developmental delay at 2 months of age showed a karyotype of 46,XX,del(5)(15.1), consistent 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 features were typical of cri du chat syndrome. The palm, middle finger and foot lengths were at or above the 95th centile for age. She was hypotonic, and her developmental level was approximately 8-10 months. Echocardiography showed redundant mitral valve tissue, mild mitral insufficiency, dilated aortic sinuses, and a small muscular VSD. We would have anticipated that a patient with an autosomal deletion who also had Marfan syndrome would have had growth failure. However, in this patient the skeletal features of Marfan syndrome (increased body length, decreased upper segment:lower segment ratio, and increased palm, finger, and foot length) predominate.